From b31fd25cc5cec96ccee737ba1313c6e9f702f32a Mon Sep 17 00:00:00 2001
From: Vincent Prouillet
Date: Fri, 26 May 2017 00:49:54 +0900
Subject: Revamp

---
 validator/Cargo.toml                               |   3 +
 validator/src/contains.rs                          |  76 ---
 validator/src/email.rs                             | 121 ----
 validator/src/ip.rs                                | 107 ----
 validator/src/length.rs                            | 108 ----
 validator/src/lib.rs                               |  35 +-
 validator/src/must_match.rs                        |  26 -
 validator/src/range.rs                             |  30 -
 validator/src/traits.rs                            |  82 +++
 validator/src/types.rs                             | 104 ++--
 validator/src/urls.rs                              |  30 -
 validator/src/validation/contains.rs               |  39 ++
 validator/src/validation/email.rs                  | 121 ++++
 validator/src/validation/ip.rs                     | 107 ++++
 validator/src/validation/length.rs                 |  72 +++
 validator/src/validation/mod.rs                    |  50 ++
 validator/src/validation/must_match.rs             |  26 +
 validator/src/validation/range.rs                  |  30 +
 validator/src/validation/urls.rs                   |  30 +
 validator_derive/Cargo.toml                        |   5 +-
 validator_derive/src/asserts.rs                    |  54 ++
 validator_derive/src/lib.rs                        | 672 +++++----------------
 validator_derive/src/lit.rs                        |  61 ++
 validator_derive/src/quoting.rs                    | 332 ++++++++++
 validator_derive/src/validation.rs                 | 290 +++++++++
 .../tests/compile-fail/length/wrong_type.rs        |   2 +-
 .../compile-fail/must_match/field_doesnt_exist.rs  |   2 +-
 .../must_match/field_type_doesnt_match.rs          |   2 +-
 .../tests/compile-fail/range/wrong_type.rs         |   2 +-
 validator_derive/tests/complex.rs                  | 155 +++++
 validator_derive/tests/contains.rs                 |  77 +++
 validator_derive/tests/custom.rs                   |  66 ++
 validator_derive/tests/email.rs                    |  77 +++
 validator_derive/tests/length.rs                   |  78 +++
 validator_derive/tests/must_match.rs               |  87 +++
 validator_derive/tests/range.rs                    |  78 +++
 validator_derive/tests/regex.rs                    |  84 +++
 validator_derive/tests/run-pass/custom.rs          |   6 +-
 validator_derive/tests/run-pass/schema.rs          |  11 +-
 validator_derive/tests/schema.rs                   |  99 +++
 validator_derive/tests/test_derive.rs              | 357 -----------
 validator_derive/tests/url.rs                      |  77 +++
 42 files changed, 2404 insertions(+), 1467 deletions(-)
 delete mode 100644 validator/src/contains.rs
 delete mode 100644 validator/src/email.rs
 delete mode 100644 validator/src/ip.rs
 delete mode 100644 validator/src/length.rs
 delete mode 100644 validator/src/must_match.rs
 delete mode 100644 validator/src/range.rs
 create mode 100644 validator/src/traits.rs
 delete mode 100644 validator/src/urls.rs
 create mode 100644 validator/src/validation/contains.rs
 create mode 100644 validator/src/validation/email.rs
 create mode 100644 validator/src/validation/ip.rs
 create mode 100644 validator/src/validation/length.rs
 create mode 100644 validator/src/validation/mod.rs
 create mode 100644 validator/src/validation/must_match.rs
 create mode 100644 validator/src/validation/range.rs
 create mode 100644 validator/src/validation/urls.rs
 create mode 100644 validator_derive/src/asserts.rs
 create mode 100644 validator_derive/src/lit.rs
 create mode 100644 validator_derive/src/quoting.rs
 create mode 100644 validator_derive/src/validation.rs
 create mode 100644 validator_derive/tests/complex.rs
 create mode 100644 validator_derive/tests/contains.rs
 create mode 100644 validator_derive/tests/custom.rs
 create mode 100644 validator_derive/tests/email.rs
 create mode 100644 validator_derive/tests/length.rs
 create mode 100644 validator_derive/tests/must_match.rs
 create mode 100644 validator_derive/tests/range.rs
 create mode 100644 validator_derive/tests/regex.rs
 create mode 100644 validator_derive/tests/schema.rs
 delete mode 100644 validator_derive/tests/test_derive.rs
 create mode 100644 validator_derive/tests/url.rs

diff --git a/validator/Cargo.toml b/validator/Cargo.toml
index c20c1ac..3565fef 100644
--- a/validator/Cargo.toml
+++ b/validator/Cargo.toml
@@ -13,3 +13,6 @@ url = "1"
 regex = "0.2"
 lazy_static = "0.2"
 idna = "0.1"
+serde = "1"
+serde_derive = "1"
+serde_json = "1"
diff --git a/validator/src/contains.rs b/validator/src/contains.rs
deleted file mode 100644
index 0c9d02e..0000000
--- a/validator/src/contains.rs
+++ /dev/null
@@ -1,76 +0,0 @@
-use std::collections::HashMap;
-
-
-/// Trait to implement if one wants to make the `contains` validator
-/// work for more types
-pub trait Contains {
-    fn has_element(&self, needle: &str) -> bool;
-}
-
-impl Contains for String {
-    fn has_element(&self, needle: &str) -> bool {
-        self.contains(needle)
-    }
-}
-
-impl<'a> Contains for &'a String {
-    fn has_element(&self, needle: &str) -> bool {
-        self.contains(needle)
-    }
-}
-
-impl<'a> Contains for &'a str {
-    fn has_element(&self, needle: &str) -> bool {
-        self.contains(needle)
-    }
-}
-
-impl<S> Contains for HashMap<String, S> {
-    fn has_element(&self, needle: &str) -> bool {
-        self.contains_key(needle)
-    }
-}
-
-impl<'a, S> Contains for &'a HashMap<String, S> {
-    fn has_element(&self, needle: &str) -> bool {
-        self.contains_key(needle)
-    }
-}
-
-/// Validates whether the value contains the needle
-/// The value needs to implement the Contains trait, which is implement on String, str and Hashmap<String>
-/// by default.
-pub fn validate_contains<T: Contains>(val: T, needle: &str) -> bool {
-    val.has_element(needle)
-}
-
-#[cfg(test)]
-mod tests {
-    use std::collections::HashMap;
-
-    use super::*;
-
-    #[test]
-    fn test_validate_contains_string() {
-        assert!(validate_contains("hey", "e"));
-    }
-
-    #[test]
-    fn test_validate_contains_string_can_fail() {
-        assert_eq!(validate_contains("hey", "o"), false);
-    }
-
-    #[test]
-    fn test_validate_contains_hashmap_key() {
-        let mut map = HashMap::new();
-        map.insert("hey".to_string(), 1);
-        assert!(validate_contains(map, "hey"));
-    }
-
-    #[test]
-    fn test_validate_contains_hashmap_key_can_fail() {
-        let mut map = HashMap::new();
-        map.insert("hey".to_string(), 1);
-        assert_eq!(validate_contains(map, "bob"), false);
-    }
-}
diff --git a/validator/src/email.rs b/validator/src/email.rs
deleted file mode 100644
index 205d89f..0000000
--- a/validator/src/email.rs
+++ /dev/null
@@ -1,121 +0,0 @@
-use regex::Regex;
-
-use ip::{validate_ip};
-use idna::{domain_to_ascii};
-
-
-lazy_static! {
-    // Regex from the specs
-    // https://html.spec.whatwg.org/multipage/forms.html#valid-e-mail-address
-    // It will mark esoteric email addresses like quoted string as invalid
-    static ref EMAIL_USER_RE: Regex = Regex::new(r"^(?i)[a-z0-9.!#$%&'*+/=?^_`{|}~-]+\z").unwrap();
-    static ref EMAIL_DOMAIN_RE: Regex = Regex::new(
-        r"(?i)^[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?(?:.[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?)*$"
-    ).unwrap();
-    // literal form, ipv4 or ipv6 address (SMTP 4.1.3)
-    static ref EMAIL_LITERAL_RE: Regex = Regex::new(r"(?i)\[([A-f0-9:\.]+)\]\z").unwrap();
-}
-
-/// Validates whether the given string is an email based on Django `EmailValidator` and HTML5 specs
-pub fn validate_email(val: &str) -> bool {
-    if val.is_empty() || !val.contains('@') {
-        return false;
-    }
-    let parts: Vec<&str> = val.rsplitn(2, '@').collect();
-    let user_part = parts[1];
-    let domain_part = parts[0];
-
-    if !EMAIL_USER_RE.is_match(user_part) {
-        return false;
-    }
-
-    if !validate_domain_part(domain_part) {
-        // Still the possibility of an [IDN](https://en.wikipedia.org/wiki/Internationalized_domain_name)
-        return match domain_to_ascii(domain_part) {
-            Ok(d) => validate_domain_part(&d),
-            Err(_) => false,
-        };
-    }
-
-    true
-}
-
-/// Checks if the domain is a valid domain and if not, check whether it's an IP
-fn validate_domain_part(domain_part: &str) -> bool {
-    if EMAIL_DOMAIN_RE.is_match(domain_part) {
-        return true;
-    }
-
-    // maybe we have an ip as a domain?
-    match EMAIL_LITERAL_RE.captures(domain_part) {
-        Some(caps) => {
-            match caps.get(1) {
-                Some(c) => validate_ip(c.as_str()),
-                None => false,
-            }
-        }
-        None => false
-    }
-}
-
-
-#[cfg(test)]
-mod tests {
-    use super::validate_email;
-
-    #[test]
-    fn test_validate_email() {
-        // Test cases taken from Django
-        // https://github.com/django/django/blob/master/tests/validators/tests.py#L48
-        let tests = vec![
-            ("email@here.com", true),
-            ("weirder-email@here.and.there.com", true),
-            (r#"!def!xyz%abc@example.com"#, true),
-            ("email@[127.0.0.1]", true),
-            ("email@[2001:dB8::1]", true),
-            ("email@[2001:dB8:0:0:0:0:0:1]", true),
-            ("email@[::fffF:127.0.0.1]", true),
-            ("example@valid-----hyphens.com", true),
-            ("example@valid-with-hyphens.com", true),
-            ("test@domain.with.idn.tld.उदाहरण.परीक्षा", true),
-            (r#""test@test"@example.com"#, false),
-            // max length for domain name labels is 63 characters per RFC 1034
-            ("a@atm.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", true),
-            ("a@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.atm", true),
-            ("a@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.bbbbbbbbbb.atm", true),
-            ("a@atm.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", true),
-            ("", false),
-            ("abc", false),
-            ("abc@", false),
-            ("abc@bar", true),
-            ("a @x.cz", false),
-            // TODO: make that one below fail
-            // ("abc@.com", false),
-            ("something@@somewhere.com", false),
-            ("email@127.0.0.1", true),
-            ("email@[127.0.0.256]", false),
-            ("email@[2001:db8::12345]", false),
-            ("email@[2001:db8:0:0:0:0:1]", false),
-            ("email@[::ffff:127.0.0.256]", false),
-            ("example@invalid-.com", false),
-            ("example@-invalid.com", false),
-            ("example@invalid.com-", false),
-            ("example@inv-.alid-.com", false),
-            ("example@inv-.-alid.com", false),
-            (r#"test@example.com\n\n<script src="x.js">"#, false),
-            (r#""\\\011"@here.com"#, false),
-            (r#""\\\012"@here.com"#, false),
-            ("trailingdot@shouldfail.com.", false),
-            // Trailing newlines in username or domain not allowed
-            ("a@b.com\n", false),
-            ("a\n@b.com", false),
-            (r#""test@test"\n@example.com"#, false),
-            ("a@[127.0.0.1]\n", false),
-        ];
-
-        for (input, expected) in tests {
-            println!("{} - {}", input, expected);
-            assert_eq!(validate_email(input), expected);
-        }
-    }
-}
diff --git a/validator/src/ip.rs b/validator/src/ip.rs
deleted file mode 100644
index 9a94522..0000000
--- a/validator/src/ip.rs
+++ /dev/null
@@ -1,107 +0,0 @@
-use std::str::FromStr;
-use std::net::IpAddr;
-
-
-/// Validates whether the given string is an IP V4
-pub fn validate_ip_v4(val: &str) -> bool {
-    match IpAddr::from_str(val) {
-        Ok(i) => match i {
-            IpAddr::V4(_) => true,
-            IpAddr::V6(_) => false,
-        },
-        Err(_) => false,
-    }
-}
-
-/// Validates whether the given string is an IP V6
-pub fn validate_ip_v6(val: &str) -> bool {
-    match IpAddr::from_str(val) {
-        Ok(i) => match i {
-            IpAddr::V4(_) => false,
-            IpAddr::V6(_) => true,
-        },
-        Err(_) => false,
-    }
-}
-
-/// Validates whether the given string is an IP
-pub fn validate_ip(val: &str) -> bool {
-    match IpAddr::from_str(val) {
-        Ok(_) => true,
-        Err(_) => false,
-    }
-}
-
-
-#[cfg(test)]
-mod tests {
-    use super::{validate_ip_v4, validate_ip_v6, validate_ip};
-
-    #[test]
-    fn test_validate_ip() {
-        let tests = vec![
-            ("1.1.1.1", true),
-            ("255.0.0.0", true),
-            ("0.0.0.0", true),
-            ("256.1.1.1", false),
-            ("25.1.1.", false),
-            ("25,1,1,1", false),
-            ("fe80::223:6cff:fe8a:2e8a", true),
-            ("::ffff:254.42.16.14", true),
-            ("2a02::223:6cff :fe8a:2e8a", false),
-        ];
-
-        for (input, expected) in tests {
-            assert_eq!(validate_ip(input), expected);
-        }
-    }
-
-    #[test]
-    fn test_validate_ip_v4() {
-        let tests = vec![
-            ("1.1.1.1", true),
-            ("255.0.0.0", true),
-            ("0.0.0.0", true),
-            ("256.1.1.1", false),
-            ("25.1.1.", false),
-            ("25,1,1,1", false),
-            ("25.1 .1.1", false),
-            ("1.1.1.1\n", false),
-            ("٧.2٥.3٣.243", false),
-        ];
-
-        for (input, expected) in tests {
-            assert_eq!(validate_ip_v4(input), expected);
-        }
-    }
-
-    #[test]
-    fn test_validate_ip_v6() {
-        let tests = vec![
-            ("fe80::223:6cff:fe8a:2e8a", true),
-            ("2a02::223:6cff:fe8a:2e8a", true),
-            ("1::2:3:4:5:6:7", true),
-            ("::", true),
-            ("::a", true),
-            ("2::", true),
-            ("::ffff:254.42.16.14", true),
-            ("::ffff:0a0a:0a0a", true),
-            ("::254.42.16.14", true),
-            ("::0a0a:0a0a", true),
-            ("foo", false),
-            ("127.0.0.1", false),
-            ("12345::", false),
-            ("1::2::3::4", false),
-            ("1::zzz", false),
-            ("1:2", false),
-            ("fe80::223: 6cff:fe8a:2e8a", false),
-            ("2a02::223:6cff :fe8a:2e8a", false),
-            ("::ffff:999.42.16.14", false),
-            ("::ffff:zzzz:0a0a", false),
-        ];
-
-        for (input, expected) in tests {
-            assert_eq!(validate_ip_v6(input), expected);
-        }
-    }
-}
diff --git a/validator/src/length.rs b/validator/src/length.rs
deleted file mode 100644
index 965d43b..0000000
--- a/validator/src/length.rs
+++ /dev/null
@@ -1,108 +0,0 @@
-use types::Validator;
-
-/// Trait to implement if one wants to make the `length` validator
-/// work for more types
-///
-/// A bit sad it's not there by default in Rust
-pub trait HasLen {
-    fn length(&self) -> u64;
-}
-
-impl HasLen for String {
-    fn length(&self) -> u64 {
-        self.chars().count() as u64
-    }
-}
-
-impl<'a> HasLen for &'a String {
-    fn length(&self) -> u64 {
-        self.chars().count() as u64
-    }
-}
-
-impl<'a> HasLen for &'a str {
-    fn length(&self) -> u64 {
-        self.chars().count() as u64
-    }
-}
-
-impl<T> HasLen for Vec<T> {
-    fn length(&self) -> u64 {
-        self.len() as u64
-    }
-}
-impl<'a, T> HasLen for &'a Vec<T> {
-    fn length(&self) -> u64 {
-        self.len() as u64
-    }
-}
-
-/// Validates the length of the value given.
-/// If the validator has `equal` set, it will ignore any `min` and `max` value.
-///
-/// If you apply it on String, don't forget that the length can be different
-/// from the number of visual characters for Unicode
-pub fn validate_length<T: HasLen>(length: Validator, val: T) -> bool {
-    match length {
-        Validator::Length { min, max, equal } => {
-            let val_length = val.length();
-            if let Some(eq) = equal {
-                return val_length == eq;
-            }
-            if let Some(m) = min {
-                if val_length < m {
-                    return false;
-                }
-            }
-            if let Some(m) = max {
-                if val_length > m {
-                    return false;
-                }
-            }
-        },
-        _ => unreachable!()
-    }
-
-    true
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{validate_length, Validator};
-
-    #[test]
-    fn test_validate_length_equal_overrides_min_max() {
-        let validator = Validator::Length { min: Some(1), max: Some(2), equal: Some(5) };
-        assert_eq!(validate_length(validator, "hello"), true);
-    }
-
-    #[test]
-    fn test_validate_length_string_min_max() {
-        let validator = Validator::Length { min: Some(1), max: Some(10), equal: None };
-        assert_eq!(validate_length(validator, "hello"), true);
-    }
-
-    #[test]
-    fn test_validate_length_string_min_only() {
-        let validator = Validator::Length { min: Some(10), max: None, equal: None };
-        assert_eq!(validate_length(validator, "hello"), false);
-    }
-
-    #[test]
-    fn test_validate_length_string_max_only() {
-        let validator = Validator::Length { min: None, max: Some(1), equal: None };
-        assert_eq!(validate_length(validator, "hello"), false);
-    }
-
-    #[test]
-    fn test_validate_length_vec() {
-        let validator = Validator::Length { min: None, max: None, equal: Some(3) };
-        assert_eq!(validate_length(validator, vec![1, 2, 3]), true);
-    }
-
-    #[test]
-    fn test_validate_length_unicode_chars() {
-        let validator = Validator::Length { min: None, max: None, equal: Some(2) };
-        assert_eq!(validate_length(validator, "日本"), true);
-    }
-}
diff --git a/validator/src/lib.rs b/validator/src/lib.rs
index 2e44b2e..35afbe4 100644
--- a/validator/src/lib.rs
+++ b/validator/src/lib.rs
@@ -1,24 +1,25 @@
 extern crate url;
 extern crate regex;
-#[macro_use] extern crate lazy_static;
+#[macro_use]
+extern crate lazy_static;
 extern crate idna;
-
+extern crate serde;
+extern crate serde_json;
+#[macro_use]
+extern crate serde_derive;
 
 mod types;
-mod ip;
-mod email;
-mod length;
-mod range;
-mod urls;
-mod must_match;
-mod contains;
+mod validation;
+mod traits;
 
+pub use validation::ip::{validate_ip, validate_ip_v4, validate_ip_v6};
+pub use validation::email::{validate_email};
+pub use validation::length::{validate_length};
+pub use validation::range::{validate_range};
+pub use validation::urls::{validate_url};
+pub use validation::must_match::{validate_must_match};
+pub use validation::contains::{validate_contains};
+pub use validation::Validator;
 
-pub use types::{Errors, Validate, Validator};
-pub use ip::{validate_ip, validate_ip_v4, validate_ip_v6};
-pub use email::{validate_email};
-pub use length::{HasLen, validate_length};
-pub use range::{validate_range};
-pub use urls::{validate_url};
-pub use must_match::{validate_must_match};
-pub use contains::{Contains, validate_contains};
+pub use types::{ValidationErrors, ValidationError};
+pub use traits::{Validate, HasLen, Contains};
diff --git a/validator/src/must_match.rs b/validator/src/must_match.rs
deleted file mode 100644
index 35fbee6..0000000
--- a/validator/src/must_match.rs
+++ /dev/null
@@ -1,26 +0,0 @@
-/// Validates that the 2 given fields match.
-/// Both fields are optionals
-pub fn validate_must_match<T: Eq>(a: T, b: T) -> bool {
-    a == b
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{validate_must_match};
-
-    #[test]
-    fn test_validate_must_match_strings_valid() {
-        assert!(validate_must_match("hey".to_string(), "hey".to_string()))
-    }
-
-    #[test]
-    fn test_validate_must_match_numbers() {
-        assert!(validate_must_match(2, 2))
-    }
-
-    #[test]
-    fn test_validate_must_match_numbers_false() {
-        assert_eq!(false, validate_must_match(2, 3));
-    }
-
-}
diff --git a/validator/src/range.rs b/validator/src/range.rs
deleted file mode 100644
index 8db9a86..0000000
--- a/validator/src/range.rs
+++ /dev/null
@@ -1,30 +0,0 @@
-use types::Validator;
-
-/// Validates that a number is in the given range
-///
-/// TODO: see if can be generic over the number type
-pub fn validate_range(range: Validator, val: f64) -> bool {
-    match range {
-        Validator::Range { min, max } => {
-            val >= min && val <= max
-        },
-        _ => unreachable!()
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{validate_range, Validator};
-
-    #[test]
-    fn test_validate_range_ok() {
-        let validator = Validator::Range { min: 0.0, max: 10.0 };
-        assert_eq!(validate_range(validator, 1 as f64), true);
-    }
-
-    #[test]
-    fn test_validate_range_fail() {
-        let validator = Validator::Range { min: 0.0, max: 10.0 };
-        assert_eq!(validate_range(validator, 20 as f64), false);
-    }
-}
diff --git a/validator/src/traits.rs b/validator/src/traits.rs
new file mode 100644
index 0000000..896fcc7
--- /dev/null
+++ b/validator/src/traits.rs
@@ -0,0 +1,82 @@
+use std::collections::HashMap;
+
+use types::ValidationErrors;
+
+
+/// Trait to implement if one wants to make the `length` validator
+/// work for more types
+///
+/// A bit sad it's not there by default in Rust
+pub trait HasLen {
+    fn length(&self) -> u64;
+}
+
+impl HasLen for String {
+    fn length(&self) -> u64 {
+        self.chars().count() as u64
+    }
+}
+
+impl<'a> HasLen for &'a String {
+    fn length(&self) -> u64 {
+        self.chars().count() as u64
+    }
+}
+
+impl<'a> HasLen for &'a str {
+    fn length(&self) -> u64 {
+        self.chars().count() as u64
+    }
+}
+
+impl<T> HasLen for Vec<T> {
+    fn length(&self) -> u64 {
+        self.len() as u64
+    }
+}
+impl<'a, T> HasLen for &'a Vec<T> {
+    fn length(&self) -> u64 {
+        self.len() as u64
+    }
+}
+
+/// Trait to implement if one wants to make the `contains` validator
+/// work for more types
+pub trait Contains {
+    fn has_element(&self, needle: &str) -> bool;
+}
+
+impl Contains for String {
+    fn has_element(&self, needle: &str) -> bool {
+        self.contains(needle)
+    }
+}
+
+impl<'a> Contains for &'a String {
+    fn has_element(&self, needle: &str) -> bool {
+        self.contains(needle)
+    }
+}
+
+impl<'a> Contains for &'a str {
+    fn has_element(&self, needle: &str) -> bool {
+        self.contains(needle)
+    }
+}
+
+impl<S> Contains for HashMap<String, S> {
+    fn has_element(&self, needle: &str) -> bool {
+        self.contains_key(needle)
+    }
+}
+
+impl<'a, S> Contains for &'a HashMap<String, S> {
+    fn has_element(&self, needle: &str) -> bool {
+        self.contains_key(needle)
+    }
+}
+
+/// The trait that `validator_derive` implements
+pub trait Validate {
+    fn validate(&self) -> Result<(), ValidationErrors>;
+}
diff --git a/validator/src/types.rs b/validator/src/types.rs
index 0a7c2fa..bb176c3 100644
--- a/validator/src/types.rs
+++ b/validator/src/types.rs
@@ -1,85 +1,61 @@
 use std::{self, fmt};
+use std::borrow::Cow;
 use std::collections::HashMap;
 
-#[derive(Debug)]
-pub struct Errors(HashMap<String, Vec<String>>);
+use serde_json::{Value, to_value};
+use serde::ser::Serialize;
 
-impl Errors {
-    pub fn new() -> Errors {
-        Errors(HashMap::new())
-    }
 
-    pub fn inner(self) -> HashMap<String, Vec<String>> {
-        self.0
-    }
+#[derive(Debug, PartialEq, Clone, Serialize, Deserialize)]
+pub struct ValidationError {
+  pub code: Cow<'static, str>,
+  pub message: Option<Cow<'static, str>>,
+  pub params: HashMap<Cow<'static, str>, Value>,
+}
 
-    pub fn add(&mut self, field: &str, err: &str) {
-        self.0.entry(field.to_string()).or_insert_with(|| vec![]).push(err.to_string());
+impl ValidationError {
+    pub fn new(code: &'static str) -> ValidationError {
+        ValidationError {
+            code: Cow::from(code),
+            message: None,
+            params: HashMap::new(),
+        }
     }
 
-    pub fn is_empty(&self) -> bool {
-        self.0.is_empty()
+    pub fn add_param<T: Serialize>(&mut self, name: Cow<'static, str>, val: &T) {
+        self.params.insert(name, to_value(val).unwrap());
     }
 }
 
-impl fmt::Display for Errors {
+impl fmt::Display for ValidationError {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "Validation failed:\n")?;
-        for (field, errs) in &self.0 {
-            write!(fmt, "    {}: [", field)?;
-
-            let last = errs.len() - 1;
-            for (index, err) in errs.iter().enumerate() {
-                write!(fmt, "{}", err)?;
-                if index < last { write!(fmt, ", ")? }
-            }
-            write!(fmt, "]\n")?;
-        }
-        Ok(())
+        write!(fmt, "Validation error: {} [{:?}]", self.code, self.params)
     }
 }
 
-impl std::error::Error for Errors {
-    fn description(&self) -> &str {
-        "validation failed"
+impl std::error::Error for ValidationError {
+  fn description(&self) -> &str { &self.code }
+  fn cause(&self) -> Option<&std::error::Error> { None }
+}
+
+#[derive(Debug, Serialize, Clone, PartialEq)]
+pub struct ValidationErrors(HashMap<&'static str, Vec<ValidationError>>);
+
+
+impl ValidationErrors {
+    pub fn new() -> ValidationErrors {
+        ValidationErrors(HashMap::new())
     }
 
-    fn cause(&self) -> Option<&std::error::Error> {
-        None
+    pub fn inner(self) -> HashMap<&'static str, Vec<ValidationError>> {
+        self.0
     }
-}
 
-pub trait Validate {
-    fn validate(&self) -> Result<(), Errors>;
-}
+    pub fn add(&mut self, field: &'static str, error: ValidationError) {
+        self.0.entry(field).or_insert_with(|| vec![]).push(error);
+    }
 
-/// Contains all the validators that can be used
-///
-/// In this crate as it's not allowed to export more than the proc macro
-/// in a proc macro crate
-#[derive(Debug, Clone)]
-pub enum Validator {
-    // String is the path to the function
-    Custom(String),
-    // String is the name of the field to match
-    MustMatch(String),
-    // value is a &str
-    Email,
-    // value is a &str
-    Url,
-    // value is a &str or a HashMap<String, ..>
-    Contains(String),
-    // value is a &str
-    Regex(String),
-    // value is a number
-    Range {
-        min: f64,
-        max: f64,
-    },
-    // value is anything that impl HasLen
-    Length {
-        min: Option<u64>,
-        max: Option<u64>,
-        equal: Option<u64>,
-    },
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
 }
diff --git a/validator/src/urls.rs b/validator/src/urls.rs
deleted file mode 100644
index d948050..0000000
--- a/validator/src/urls.rs
+++ /dev/null
@@ -1,30 +0,0 @@
-use url::Url;
-
-
-/// Validates whether the string given is a url
-pub fn validate_url(val: &str) -> bool {
-    match Url::parse(val) {
-        Ok(_) => true,
-        Err(_) => false,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{validate_url};
-
-
-    #[test]
-    fn test_validate_url() {
-        let tests = vec![
-            ("http", false),
-            ("https://google.com", true),
-            ("http://localhost:80", true),
-            ("ftp://localhost:80", true),
-        ];
-
-        for (url, expected) in tests {
-            assert_eq!(validate_url(url), expected);
-        }
-    }
-}
diff --git a/validator/src/validation/contains.rs b/validator/src/validation/contains.rs
new file mode 100644
index 0000000..58baabe
--- /dev/null
+++ b/validator/src/validation/contains.rs
@@ -0,0 +1,39 @@
+use traits::Contains;
+
+/// Validates whether the value contains the needle
+/// The value needs to implement the Contains trait, which is implement on String, str and Hashmap<String>
+/// by default.
+pub fn validate_contains<T: Contains>(val: T, needle: &str) -> bool {
+    val.has_element(needle)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashMap;
+
+    use super::*;
+
+    #[test]
+    fn test_validate_contains_string() {
+        assert!(validate_contains("hey", "e"));
+    }
+
+    #[test]
+    fn test_validate_contains_string_can_fail() {
+        assert_eq!(validate_contains("hey", "o"), false);
+    }
+
+    #[test]
+    fn test_validate_contains_hashmap_key() {
+        let mut map = HashMap::new();
+        map.insert("hey".to_string(), 1);
+        assert!(validate_contains(map, "hey"));
+    }
+
+    #[test]
+    fn test_validate_contains_hashmap_key_can_fail() {
+        let mut map = HashMap::new();
+        map.insert("hey".to_string(), 1);
+        assert_eq!(validate_contains(map, "bob"), false);
+    }
+}
diff --git a/validator/src/validation/email.rs b/validator/src/validation/email.rs
new file mode 100644
index 0000000..cf6adc5
--- /dev/null
+++ b/validator/src/validation/email.rs
@@ -0,0 +1,121 @@
+use regex::Regex;
+use idna::domain_to_ascii;
+
+use validation::ip::validate_ip;
+
+
+lazy_static! {
+    // Regex from the specs
+    // https://html.spec.whatwg.org/multipage/forms.html#valid-e-mail-address
+    // It will mark esoteric email addresses like quoted string as invalid
+    static ref EMAIL_USER_RE: Regex = Regex::new(r"^(?i)[a-z0-9.!#$%&'*+/=?^_`{|}~-]+\z").unwrap();
+    static ref EMAIL_DOMAIN_RE: Regex = Regex::new(
+        r"(?i)^[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?(?:.[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?)*$"
+    ).unwrap();
+    // literal form, ipv4 or ipv6 address (SMTP 4.1.3)
+    static ref EMAIL_LITERAL_RE: Regex = Regex::new(r"(?i)\[([A-f0-9:\.]+)\]\z").unwrap();
+}
+
+/// Validates whether the given string is an email based on Django `EmailValidator` and HTML5 specs
+pub fn validate_email(val: &str) -> bool {
+    if val.is_empty() || !val.contains('@') {
+        return false;
+    }
+    let parts: Vec<&str> = val.rsplitn(2, '@').collect();
+    let user_part = parts[1];
+    let domain_part = parts[0];
+
+    if !EMAIL_USER_RE.is_match(user_part) {
+        return false;
+    }
+
+    if !validate_domain_part(domain_part) {
+        // Still the possibility of an [IDN](https://en.wikipedia.org/wiki/Internationalized_domain_name)
+        return match domain_to_ascii(domain_part) {
+            Ok(d) => validate_domain_part(&d),
+            Err(_) => false,
+        };
+    }
+
+    true
+}
+
+/// Checks if the domain is a valid domain and if not, check whether it's an IP
+fn validate_domain_part(domain_part: &str) -> bool {
+    if EMAIL_DOMAIN_RE.is_match(domain_part) {
+        return true;
+    }
+
+    // maybe we have an ip as a domain?
+    match EMAIL_LITERAL_RE.captures(domain_part) {
+        Some(caps) => {
+            match caps.get(1) {
+                Some(c) => validate_ip(c.as_str()),
+                None => false,
+            }
+        }
+        None => false
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::validate_email;
+
+    #[test]
+    fn test_validate_email() {
+        // Test cases taken from Django
+        // https://github.com/django/django/blob/master/tests/validators/tests.py#L48
+        let tests = vec![
+            ("email@here.com", true),
+            ("weirder-email@here.and.there.com", true),
+            (r#"!def!xyz%abc@example.com"#, true),
+            ("email@[127.0.0.1]", true),
+            ("email@[2001:dB8::1]", true),
+            ("email@[2001:dB8:0:0:0:0:0:1]", true),
+            ("email@[::fffF:127.0.0.1]", true),
+            ("example@valid-----hyphens.com", true),
+            ("example@valid-with-hyphens.com", true),
+            ("test@domain.with.idn.tld.उदाहरण.परीक्षा", true),
+            (r#""test@test"@example.com"#, false),
+            // max length for domain name labels is 63 characters per RFC 1034
+            ("a@atm.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", true),
+            ("a@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.atm", true),
+            ("a@aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.bbbbbbbbbb.atm", true),
+            ("a@atm.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", true),
+            ("", false),
+            ("abc", false),
+            ("abc@", false),
+            ("abc@bar", true),
+            ("a @x.cz", false),
+            // TODO: make that one below fail
+            // ("abc@.com", false),
+            ("something@@somewhere.com", false),
+            ("email@127.0.0.1", true),
+            ("email@[127.0.0.256]", false),
+            ("email@[2001:db8::12345]", false),
+            ("email@[2001:db8:0:0:0:0:1]", false),
+            ("email@[::ffff:127.0.0.256]", false),
+            ("example@invalid-.com", false),
+            ("example@-invalid.com", false),
+            ("example@invalid.com-", false),
+            ("example@inv-.alid-.com", false),
+            ("example@inv-.-alid.com", false),
+            (r#"test@example.com\n\n<script src="x.js">"#, false),
+            (r#""\\\011"@here.com"#, false),
+            (r#""\\\012"@here.com"#, false),
+            ("trailingdot@shouldfail.com.", false),
+            // Trailing newlines in username or domain not allowed
+            ("a@b.com\n", false),
+            ("a\n@b.com", false),
+            (r#""test@test"\n@example.com"#, false),
+            ("a@[127.0.0.1]\n", false),
+        ];
+
+        for (input, expected) in tests {
+            println!("{} - {}", input, expected);
+            assert_eq!(validate_email(input), expected);
+        }
+    }
+}
diff --git a/validator/src/validation/ip.rs b/validator/src/validation/ip.rs
new file mode 100644
index 0000000..9a94522
--- /dev/null
+++ b/validator/src/validation/ip.rs
@@ -0,0 +1,107 @@
+use std::str::FromStr;
+use std::net::IpAddr;
+
+
+/// Validates whether the given string is an IP V4
+pub fn validate_ip_v4(val: &str) -> bool {
+    match IpAddr::from_str(val) {
+        Ok(i) => match i {
+            IpAddr::V4(_) => true,
+            IpAddr::V6(_) => false,
+        },
+        Err(_) => false,
+    }
+}
+
+/// Validates whether the given string is an IP V6
+pub fn validate_ip_v6(val: &str) -> bool {
+    match IpAddr::from_str(val) {
+        Ok(i) => match i {
+            IpAddr::V4(_) => false,
+            IpAddr::V6(_) => true,
+        },
+        Err(_) => false,
+    }
+}
+
+/// Validates whether the given string is an IP
+pub fn validate_ip(val: &str) -> bool {
+    match IpAddr::from_str(val) {
+        Ok(_) => true,
+        Err(_) => false,
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::{validate_ip_v4, validate_ip_v6, validate_ip};
+
+    #[test]
+    fn test_validate_ip() {
+        let tests = vec![
+            ("1.1.1.1", true),
+            ("255.0.0.0", true),
+            ("0.0.0.0", true),
+            ("256.1.1.1", false),
+            ("25.1.1.", false),
+            ("25,1,1,1", false),
+            ("fe80::223:6cff:fe8a:2e8a", true),
+            ("::ffff:254.42.16.14", true),
+            ("2a02::223:6cff :fe8a:2e8a", false),
+        ];
+
+        for (input, expected) in tests {
+            assert_eq!(validate_ip(input), expected);
+        }
+    }
+
+    #[test]
+    fn test_validate_ip_v4() {
+        let tests = vec![
+            ("1.1.1.1", true),
+            ("255.0.0.0", true),
+            ("0.0.0.0", true),
+            ("256.1.1.1", false),
+            ("25.1.1.", false),
+            ("25,1,1,1", false),
+            ("25.1 .1.1", false),
+            ("1.1.1.1\n", false),
+            ("٧.2٥.3٣.243", false),
+        ];
+
+        for (input, expected) in tests {
+            assert_eq!(validate_ip_v4(input), expected);
+        }
+    }
+
+    #[test]
+    fn test_validate_ip_v6() {
+        let tests = vec![
+            ("fe80::223:6cff:fe8a:2e8a", true),
+            ("2a02::223:6cff:fe8a:2e8a", true),
+            ("1::2:3:4:5:6:7", true),
+            ("::", true),
+            ("::a", true),
+            ("2::", true),
+            ("::ffff:254.42.16.14", true),
+            ("::ffff:0a0a:0a0a", true),
+            ("::254.42.16.14", true),
+            ("::0a0a:0a0a", true),
+            ("foo", false),
+            ("127.0.0.1", false),
+            ("12345::", false),
+            ("1::2::3::4", false),
+            ("1::zzz", false),
+            ("1:2", false),
+            ("fe80::223: 6cff:fe8a:2e8a", false),
+            ("2a02::223:6cff :fe8a:2e8a", false),
+            ("::ffff:999.42.16.14", false),
+            ("::ffff:zzzz:0a0a", false),
+        ];
+
+        for (input, expected) in tests {
+            assert_eq!(validate_ip_v6(input), expected);
+        }
+    }
+}
diff --git a/validator/src/validation/length.rs b/validator/src/validation/length.rs
new file mode 100644
index 0000000..1c3affc
--- /dev/null
+++ b/validator/src/validation/length.rs
@@ -0,0 +1,72 @@
+use validation::Validator;
+use traits::HasLen;
+
+/// Validates the length of the value given.
+/// If the validator has `equal` set, it will ignore any `min` and `max` value.
+///
+/// If you apply it on String, don't forget that the length can be different
+/// from the number of visual characters for Unicode
+pub fn validate_length<T: HasLen>(length: Validator, val: T) -> bool {
+    match length {
+        Validator::Length { min, max, equal } => {
+            let val_length = val.length();
+            if let Some(eq) = equal {
+                return val_length == eq;
+            }
+            if let Some(m) = min {
+                if val_length < m {
+                    return false;
+                }
+            }
+            if let Some(m) = max {
+                if val_length > m {
+                    return false;
+                }
+            }
+        },
+        _ => unreachable!()
+    }
+
+    true
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{validate_length, Validator};
+
+    #[test]
+    fn test_validate_length_equal_overrides_min_max() {
+        let validator = Validator::Length { min: Some(1), max: Some(2), equal: Some(5) };
+        assert_eq!(validate_length(validator, "hello"), true);
+    }
+
+    #[test]
+    fn test_validate_length_string_min_max() {
+        let validator = Validator::Length { min: Some(1), max: Some(10), equal: None };
+        assert_eq!(validate_length(validator, "hello"), true);
+    }
+
+    #[test]
+    fn test_validate_length_string_min_only() {
+        let validator = Validator::Length { min: Some(10), max: None, equal: None };
+        assert_eq!(validate_length(validator, "hello"), false);
+    }
+
+    #[test]
+    fn test_validate_length_string_max_only() {
+        let validator = Validator::Length { min: None, max: Some(1), equal: None };
+        assert_eq!(validate_length(validator, "hello"), false);
+    }
+
+    #[test]
+    fn test_validate_length_vec() {
+        let validator = Validator::Length { min: None, max: None, equal: Some(3) };
+        assert_eq!(validate_length(validator, vec![1, 2, 3]), true);
+    }
+
+    #[test]
+    fn test_validate_length_unicode_chars() {
+        let validator = Validator::Length { min: None, max: None, equal: Some(2) };
+        assert_eq!(validate_length(validator, "日本"), true);
+    }
+}
diff --git a/validator/src/validation/mod.rs b/validator/src/validation/mod.rs
new file mode 100644
index 0000000..939cacf
--- /dev/null
+++ b/validator/src/validation/mod.rs
@@ -0,0 +1,50 @@
+pub mod ip;
+pub mod email;
+pub mod length;
+pub mod range;
+pub mod urls;
+pub mod must_match;
+pub mod contains;
+
+/// Contains all the validators that can be used
+///
+/// In this crate as it's not allowed to export more than the proc macro
+/// in a proc macro crate
+#[derive(Debug, Clone, PartialEq)]
+pub enum Validator {
+    Email,
+    Url,
+    // String is the path to the function
+    Custom(String),
+    // String is the name of the field to match
+    MustMatch(String),
+    // value is a &str or a HashMap<String, ..>
+    Contains(String),
+    // No implementation in this crate, it's all in validator_derive
+    Regex(String),
+    Range {
+        min: f64,
+        max: f64,
+    },
+    // Any value that impl HasLen can be validated with Length
+    Length {
+        min: Option<u64>,
+        max: Option<u64>,
+        equal: Option<u64>,
+    },
+}
+
+impl Validator {
+    pub fn code(&self) -> &'static str {
+        match *self {
+            Validator::MustMatch(_) => "must_match",
+            Validator::Email => "email",
+            Validator::Url => "url",
+            Validator::Custom(_) => "custom",
+            Validator::Contains(_) => "contains",
+            Validator::Regex(_) => "regex",
+            Validator::Range {..} => "range",
+            Validator::Length {..} => "length",
+        }
+    }
+}
diff --git a/validator/src/validation/must_match.rs b/validator/src/validation/must_match.rs
new file mode 100644
index 0000000..35fbee6
--- /dev/null
+++ b/validator/src/validation/must_match.rs
@@ -0,0 +1,26 @@
+/// Validates that the 2 given fields match.
+/// Both fields are optionals
+pub fn validate_must_match<T: Eq>(a: T, b: T) -> bool {
+    a == b
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{validate_must_match};
+
+    #[test]
+    fn test_validate_must_match_strings_valid() {
+        assert!(validate_must_match("hey".to_string(), "hey".to_string()))
+    }
+
+    #[test]
+    fn test_validate_must_match_numbers() {
+        assert!(validate_must_match(2, 2))
+    }
+
+    #[test]
+    fn test_validate_must_match_numbers_false() {
+        assert_eq!(false, validate_must_match(2, 3));
+    }
+
+}
diff --git a/validator/src/validation/range.rs b/validator/src/validation/range.rs
new file mode 100644
index 0000000..8cb9ec7
--- /dev/null
+++ b/validator/src/validation/range.rs
@@ -0,0 +1,30 @@
+use validation::Validator;
+
+/// Validates that a number is in the given range
+///
+/// TODO: see if can be generic over the number type
+pub fn validate_range(range: Validator, val: f64) -> bool {
+    match range {
+        Validator::Range { min, max } => {
+            val >= min && val <= max
+        },
+        _ => unreachable!()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{validate_range, Validator};
+
+    #[test]
+    fn test_validate_range_ok() {
+        let validator = Validator::Range { min: 0.0, max: 10.0 };
+        assert_eq!(validate_range(validator, 1 as f64), true);
+    }
+
+    #[test]
+    fn test_validate_range_fail() {
+        let validator = Validator::Range { min: 0.0, max: 10.0 };
+        assert_eq!(validate_range(validator, 20 as f64), false);
+    }
+}
diff --git a/validator/src/validation/urls.rs b/validator/src/validation/urls.rs
new file mode 100644
index 0000000..d948050
--- /dev/null
+++ b/validator/src/validation/urls.rs
@@ -0,0 +1,30 @@
+use url::Url;
+
+
+/// Validates whether the string given is a url
+pub fn validate_url(val: &str) -> bool {
+    match Url::parse(val) {
+        Ok(_) => true,
+        Err(_) => false,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{validate_url};
+
+
+    #[test]
+    fn test_validate_url() {
+        let tests = vec![
+            ("http", false),
+            ("https://google.com", true),
+            ("http://localhost:80", true),
+            ("ftp://localhost:80", true),
+        ];
+
+        for (url, expected) in tests {
+            assert_eq!(validate_url(url), expected);
+        }
+    }
+}
diff --git a/validator_derive/Cargo.toml b/validator_derive/Cargo.toml
index d5a1f5e..127ae9e 100644
--- a/validator_derive/Cargo.toml
+++ b/validator_derive/Cargo.toml
@@ -14,6 +14,7 @@ proc-macro = true
 [dependencies]
 syn = "0.11"
 quote = "0.3"
+if_chain = "0"
 
 [dev-dependencies]
 serde = "1.0"
@@ -24,5 +25,5 @@ regex = "0.2"
 lazy_static = "0.2"
 
 [dependencies.validator]
-# path = "../validator"
-version = "0.4.0"
+path = "../validator"
+# version = "0.4.0"
diff --git a/validator_derive/src/asserts.rs b/validator_derive/src/asserts.rs
new file mode 100644
index 0000000..65db5cf
--- /dev/null
+++ b/validator_derive/src/asserts.rs
@@ -0,0 +1,54 @@
+
+pub static NUMBER_TYPES: [&'static str; 24] = [
+    "usize", "u8", "u16", "u32", "u64",
+    "isize", "i8", "i16", "i32", "i64",
+    "f32", "f64",
+
+    "Option<usize>", "Option<u8>", "Option<u16>", "Option<u32>", "Option<u64>",
+    "Option<isize>", "Option<i8>", "Option<i16>", "Option<i32>", "Option<i64>",
+    "Option<f32>", "Option<f64>",
+];
+
+
+pub fn assert_string_type(name: &str, field_type: &String) {
+    if field_type != "String"
+        && field_type != "&str"
+        && field_type != "Option<String>"
+        && !(field_type.starts_with("Option<") && field_type.ends_with("str>")) {
+        panic!("`{}` validator can only be used on String, &str or an Option of those", name);
+    }
+}
+
+pub fn assert_type_matches(field_name: String, field_type: &String, field_type2: Option<&String>) {
+    if let Some(t2) = field_type2 {
+        if field_type != t2 {
+            panic!("Invalid argument for `must_match` validator of field `{}`: types of field can't match", field_name);
+        }
+    } else {
+        panic!("Invalid argument for `must_match` validator of field `{}`: the other field doesn't exist in struct", field_name);
+    }
+}
+
+pub fn assert_has_len(field_name: String, field_type: &String) {
+    if field_type != "String"
+        && !field_type.starts_with("Vec<")
+        && !field_type.starts_with("Option<Vec<")
+        && field_type != "Option<String>"
+        // a bit ugly
+        && !(field_type.starts_with("Option<") && field_type.ends_with("str>"))
+        && field_type != "&str" {
+            panic!(
+                "Validator `length` can only be used on types `String`, `&str` or `Vec` but found `{}` for field `{}`",
+                field_type, field_name
+            );
+    }
+}
+
+pub fn assert_has_range(field_name: String, field_type: &String) {
+    if !NUMBER_TYPES.contains(&field_type.as_ref()) {
+        panic!(
+            "Validator `range` can only be used on number types but found `{}` for field `{}`",
+            field_type, field_name
+        );
+    }
+}
diff --git a/validator_derive/src/lib.rs b/validator_derive/src/lib.rs
index 6bc8313..1298006 100644
--- a/validator_derive/src/lib.rs
+++ b/validator_derive/src/lib.rs
@@ -1,33 +1,31 @@
 #![recursion_limit = "128"]
 
 
-#[macro_use] extern crate quote;
+#[macro_use]
+extern crate quote;
 extern crate proc_macro;
 extern crate syn;
+#[macro_use]
+extern crate if_chain;
 extern crate validator;
 
 use std::collections::HashMap;
 
 use proc_macro::TokenStream;
 use quote::ToTokens;
-use validator::{Validator};
 
+use validator::Validator;
 
-static RANGE_TYPES: [&'static str; 24] = [
-    "usize", "u8", "u16", "u32", "u64",
-    "isize", "i8", "i16", "i32", "i64",
-    "f32", "f64",
 
-    "Option<usize>", "Option<u8>", "Option<u16>", "Option<u32>", "Option<u64>",
-    "Option<isize>", "Option<i8>", "Option<i16>", "Option<i32>", "Option<i64>",
-    "Option<f32>", "Option<f64>",
-];
+mod lit;
+mod validation;
+mod asserts;
+mod quoting;
 
-#[derive(Debug)]
-struct SchemaValidation {
-    function: String,
-    skip_on_field_errors: bool,
-}
+use lit::*;
+use validation::*;
+use asserts::{assert_string_type, assert_type_matches, assert_has_len, assert_has_range};
+use quoting::{FieldQuoter, quote_field_validation, quote_schema_validation};
 
 
 #[proc_macro_derive(Validate, attributes(validate))]
@@ -36,12 +34,13 @@ pub fn derive_validation(input: TokenStream) -> TokenStream {
     // Parse the string representation to an AST
     let ast = syn::parse_macro_input(&source).unwrap();
 
-    let expanded = expand_validation(&ast);
+    let expanded = impl_validate(&ast);
     expanded.parse().unwrap()
 }
 
 
-fn expand_validation(ast: &syn::MacroInput) -> quote::Tokens {
+fn impl_validate(ast: &syn::MacroInput) -> quote::Tokens {
+    // Ensure the macro is on a struct with named fields
     let fields = match ast.body {
         syn::Body::Struct(syn::VariantData::Struct(ref fields)) => {
             if fields.iter().any(|field| field.ident.is_none()) {
@@ -57,228 +56,17 @@ fn expand_validation(ast: &syn::MacroInput) -> quote::Tokens {
     let field_types = find_fields_type(&fields);
 
     for field in fields {
-        let field_ident = match field.ident {
-            Some(ref i) => i,
-            None => unreachable!()
-        };
-
-        let (name, validators) = find_validators_for_field(field, &field_types);
-        let field_name = field_types.get(&field_ident.to_string()).unwrap();
-        // Don't put a & in front a pointer
-        let validator_param = if field_name.starts_with("&") {
-          quote!(self.#field_ident)
-        } else {
-          quote!(&self.#field_ident)
-        };
-        // same but for the ident used in a if let block
-        let optional_validator_param = quote!(#field_ident);
-        // same but for the ident used in a if let Some variable
-        let optional_pattern_matched = if field_name.starts_with("Option<&") {
-          quote!(#field_ident)
-        } else {
-          quote!(ref #field_ident)
-        };
+        let field_ident = field.ident.clone().unwrap();
+        let (name, field_validations) = find_validators_for_field(field, &field_types);
+        let field_type = field_types.get(&field_ident.to_string()).cloned().unwrap();
+        let field_quoter = FieldQuoter::new(field_ident, name, field_type);
 
-        for validator in &validators {
-            validations.push(match validator {
-                &Validator::Length {min, max, equal} =>  {
-                    // Can't interpolate None
-                    let min_tokens = option_u64_to_tokens(min);
-                    let max_tokens = option_u64_to_tokens(max);
-                    let equal_tokens = option_u64_to_tokens(equal);
-                    // wrap in if-let if we have an option
-                    if field_name.starts_with("Option<") {
-                        quote!(
-                            if let Some(#optional_pattern_matched) = self.#field_ident {
-                                if !::validator::validate_length(
-                                    ::validator::Validator::Length {
-                                        min: #min_tokens,
-                                        max: #max_tokens,
-                                        equal: #equal_tokens
-                                    },
-                                    #optional_validator_param
-                                ) {
-                                    errors.add(#name, "length");
-                                }
-                            }
-                        )
-                    } else {
-                        quote!(
-                            if !::validator::validate_length(
-                                ::validator::Validator::Length {
-                                    min: #min_tokens,
-                                    max: #max_tokens,
-                                    equal: #equal_tokens
-                                },
-                                #validator_param
-                            ) {
-                                errors.add(#name, "length");
-                            }
-                        )
-                    }
-                },
-                &Validator::Range {min, max} => {
-                    // wrap in if-let if we have an option
-                    if field_name.starts_with("Option<") {
-                        quote!(
-                            if let Some(#field_ident) = self.#field_ident {
-                                if !::validator::validate_range(
-                                    ::validator::Validator::Range {min: #min, max: #max},
-                                    #field_ident as f64
-                                ) {
-                                    errors.add(#name, "range");
-                                }
-                            }
-                        )
-                    } else {
-                        quote!(
-                            if !::validator::validate_range(
-                                ::validator::Validator::Range {min: #min, max: #max},
-                                self.#field_ident as f64
-                            ) {
-                                errors.add(#name, "range");
-                            }
-                        )
-                    }
-                },
-                &Validator::Email => {
-                    // wrap in if-let if we have an option
-                    if field_name.starts_with("Option<") {
-                        quote!(
-                            if let Some(#optional_pattern_matched) = self.#field_ident {
-                                if !::validator::validate_email(#optional_validator_param) {
-                                    errors.add(#name, "email");
-                                }
-                            }
-                        )
-                    } else {
-                        quote!(
-                            if !::validator::validate_email(#validator_param) {
-                                errors.add(#name, "email");
-                            }
-                        )
-                    }
-                }
-                &Validator::Url => {
-                    // wrap in if-let if we have an option
-                    if field_name.starts_with("Option<") {
-                        quote!(
-                            if let Some(#optional_pattern_matched) = self.#field_ident {
-                                if !::validator::validate_url(#optional_validator_param) {
-                                    errors.add(#name, "url");
-                                }
-                            }
-                        )
-                    } else {
-                        quote!(
-                            if !::validator::validate_url(#validator_param) {
-                                errors.add(#name, "url");
-                            }
-                        )
-                    }
-                },
-                &Validator::MustMatch(ref f) => {
-                    let other_ident = syn::Ident::new(f.clone());
-                    quote!(
-                        if !::validator::validate_must_match(&self.#field_ident, &self.#other_ident) {
-                            errors.add(#name, "no_match");
-                        }
-                    )
-                },
-                &Validator::Custom(ref f) => {
-                    let fn_ident = syn::Ident::new(f.clone());
-                    // wrap in if-let if we have an option
-                    if field_name.starts_with("Option<") {
-                        quote!(
-                            if let Some(#optional_pattern_matched) = self.#field_ident {
-                                match #fn_ident(#optional_validator_param) {
-                                    ::std::option::Option::Some(s) => {
-                                        errors.add(#name, &s);
-                                    },
-                                    ::std::option::Option::None => (),
-                                };
-                            }
-                        )
-                    } else {
-                        quote!(
-                            match #fn_ident(#validator_param) {
-                                ::std::option::Option::Some(s) => {
-                                    errors.add(#name, &s);
-                                },
-                                ::std::option::Option::None => (),
-                            };
-                        )
-                    }
-                },
-                &Validator::Contains(ref n) => {
-                    // wrap in if-let if we have an option
-                    if field_name.starts_with("Option<") {
-                        quote!(
-                            if let Some(#optional_pattern_matched) = self.#field_ident {
-                                if !::validator::validate_contains(#optional_validator_param, &#n) {
-                                    errors.add(#name, "contains");
-                                }
-                            }
-                        )
-                    } else {
-                        quote!(
-                            if !::validator::validate_contains(#validator_param, &#n) {
-                                errors.add(#name, "contains");
-                            }
-                        )
-                    }
-                },
-                &Validator::Regex(ref re) => {
-                    let re_ident = syn::Ident::new(re.clone());
-                    // wrap in if-let if we have an option
-                    if field_name.starts_with("Option<") {
-                        quote!(
-                            if let Some(#optional_pattern_matched) = self.#field_ident {
-                                if !#re_ident.is_match(#optional_validator_param) {
-                                    errors.add(#name, "regex");
-                                }
-                            }
-                        )
-                    } else {
-                        quote!(
-                            if !#re_ident.is_match(#validator_param) {
-                                errors.add(#name, "regex");
-                            }
-                        )
-                    }
-                },
-            });
+        for validation in &field_validations {
+            validations.push(quote_field_validation(&field_quoter, validation));
         }
     }
 
-    let struct_validation = find_struct_validation(&ast.attrs);
-    let struct_validation_tokens = match struct_validation {
-        Some(s) => {
-            let fn_ident = syn::Ident::new(s.function);
-            if s.skip_on_field_errors {
-                quote!(
-                    if errors.is_empty() {
-                        match #fn_ident(self) {
-                            ::std::option::Option::Some((key, val)) => {
-                                errors.add(&key, &val);
-                            },
-                            ::std::option::Option::None => (),
-                        }
-                    }
-                )
-            } else {
-                quote!(
-                    match #fn_ident(self) {
-                        ::std::option::Option::Some((key, val)) => {
-                            errors.add(&key, &val);
-                        },
-                        ::std::option::Option::None => (),
-                    }
-                )
-            }
-        },
-        None => quote!()
-    };
+    let schema_validation = quote_schema_validation(find_struct_validation(&ast.attrs));
 
     let ident = &ast.ident;
 
@@ -286,12 +74,12 @@ fn expand_validation(ast: &syn::MacroInput) -> quote::Tokens {
     let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
     let impl_ast = quote!(
         impl #impl_generics Validate for #ident #ty_generics #where_clause {
-            fn validate(&self) -> ::std::result::Result<(), ::validator::Errors> {
-                let mut errors = ::validator::Errors::new();
+            fn validate(&self) -> ::std::result::Result<(), ::validator::ValidationErrors> {
+                let mut errors = ::validator::ValidationErrors::new();
 
                 #(#validations)*
 
-                #struct_validation_tokens
+                #schema_validation
 
                 if errors.is_empty() {
                     ::std::result::Result::Ok(())
@@ -316,61 +104,80 @@ fn find_struct_validation(struct_attrs: &Vec<syn::Attribute>) -> Option<SchemaVa
         if attr.value.name() != "validate" {
             continue;
         }
-        match attr.value {
-            syn::MetaItem::List(_, ref meta_items) => {
-                match meta_items[0] {
-                    syn::NestedMetaItem::MetaItem(ref item) => match item {
-                        &syn::MetaItem::List(ref ident2, ref args) => {
-                            if ident2 != "schema" {
-                                error("Only `schema` is allowed as validator on a struct")
-                            }
 
-                            let mut function = "".to_string();
-                            let mut skip_on_field_errors = true;
-                            for arg in args {
-                                match *arg {
-                                    syn::NestedMetaItem::MetaItem(ref item) => match *item {
-                                        syn::MetaItem::NameValue(ref name, ref val) => {
-                                            match name.to_string().as_ref() {
-                                                "function" => {
-                                                    function = match lit_to_string(val) {
-                                                        Some(s) => s,
-                                                        None => error("invalid argument type for `function` \
-                                                        : only a string is allowed"),
-                                                    };
-                                                },
-                                                "skip_on_field_errors" => {
-                                                    skip_on_field_errors = match lit_to_bool(val) {
-                                                        Some(s) => s,
-                                                        None => error("invalid argument type for `skip_on_field_errors` \
-                                                        : only a bool is allowed"),
-                                                    };
-                                                },
-                                                _ => error("Unknown argument")
-                                            }
-
-                                        },
-                                        _ => error("Unexpected args")
-                                    },
-                                    _ => error("Unexpected args")
-                                }
-                            }
+        if_chain! {
+            if let syn::MetaItem::List(_, ref meta_items) = attr.value;
+            if let syn::NestedMetaItem::MetaItem(ref item) = meta_items[0];
+            if let &syn::MetaItem::List(ref ident2, ref args) = item;
+
+            then {
+                if ident2 != "schema" {
+                    error("Only `schema` is allowed as validator on a struct")
+                }
 
-                            if function == "" {
-                                error("`function` is required");
+                let mut function = String::new();
+                let mut skip_on_field_errors = true;
+                let mut code = None;
+                let mut message = None;
+
+                for arg in args {
+                    if_chain! {
+                        if let syn::NestedMetaItem::MetaItem(ref item) = *arg;
+                        if let syn::MetaItem::NameValue(ref name, ref val) = *item;
+
+                        then {
+                            match name.to_string().as_ref() {
+                                "function" => {
+                                    function = match lit_to_string(val) {
+                                        Some(s) => s,
+                                        None => error("invalid argument type for `function` \
+                                        : only a string is allowed"),
+                                    };
+                                },
+                                "skip_on_field_errors" => {
+                                    skip_on_field_errors = match lit_to_bool(val) {
+                                        Some(s) => s,
+                                        None => error("invalid argument type for `skip_on_field_errors` \
+                                        : only a bool is allowed"),
+                                    };
+                                },
+                                "code" => {
+                                    code = match lit_to_string(val) {
+                                        Some(s) => Some(s),
+                                        None => error("invalid argument type for `code` \
+                                        : only a string is allowed"),
+                                    };
+                                },
+                                "message" => {
+                                    message = match lit_to_string(val) {
+                                        Some(s) => Some(s),
+                                        None => error("invalid argument type for `message` \
+                                        : only a string is allowed"),
+                                    };
+                                },
+                                _ => error("Unknown argument")
                             }
+                        } else {
+                            error("Unexpected args")
+                        }
+                    }
+                }
 
-                            return Some(SchemaValidation {
-                                function: function,
-                                skip_on_field_errors: skip_on_field_errors
-                            });
-                        },
-                        _ => error("Unexpected struct validator")
-                    },
-                    _ => error("Unexpected struct validator")
+                if function == "" {
+                    error("`function` is required");
                 }
-            },
-            _ => error("Unexpected struct validator")
+
+                return Some(
+                    SchemaValidation {
+                        function,
+                        skip_on_field_errors,
+                        code,
+                        message,
+                    }
+                );
+            } else {
+                error("Unexpected struct validator")
+            }
         }
     }
 
@@ -378,16 +185,13 @@ fn find_struct_validation(struct_attrs: &Vec<syn::Attribute>) -> Option<SchemaVa
 }
 
 
-// Find all the types (as string) for each field of the struct
-// Needed for the `must_match` filter
+/// Find the types (as string) for each field of the struct
+/// Needed for the `must_match` filter
 fn find_fields_type(fields: &Vec<syn::Field>) -> HashMap<String, String> {
     let mut types = HashMap::new();
 
     for field in fields {
-        let field_name = match field.ident {
-            Some(ref s) => s.to_string(),
-            None => unreachable!(),
-        };
+        let field_ident = field.ident.clone().unwrap().to_string();
         let field_type = match field.ty {
             syn::Ty::Path(_, ref p) => {
                 let mut tokens = quote::Tokens::new();
@@ -404,114 +208,31 @@ fn find_fields_type(fields: &Vec<syn::Field>) -> HashMap<String, String> {
                 }
                 name
             },
-            _ => panic!("Type `{:?}` of field `{}` not supported", field.ty, field_name)
+            _ => panic!("Type `{:?}` of field `{}` not supported", field.ty, field_ident)
         };
+
         //println!("{:?}", field_type);
-        types.insert(field_name, field_type);
+        types.insert(field_ident, field_type);
     }
 
     types
 }
 
-/// Find everything we need to know about a Field.
-fn find_validators_for_field(field: &syn::Field, field_types: &HashMap<String, String>) -> (String, Vec<Validator>) {
-    let mut field_name = match field.ident {
-        Some(ref s) => s.to_string(),
-        None => unreachable!(),
-    };
+/// Find everything we need to know about a field: its real name if it's changed from the serialization
+/// and the list of validators to run on it
+fn find_validators_for_field(field: &syn::Field, field_types: &HashMap<String, String>) -> (String, Vec<FieldValidation>) {
+    let rust_ident = field.ident.clone().unwrap().to_string();
+    let mut field_ident = field.ident.clone().unwrap().to_string();
 
     let error = |msg: &str| -> ! {
         panic!("Invalid attribute #[validate] on field `{}`: {}", field.ident.clone().unwrap().to_string(), msg);
     };
-    let field_type = field_types.get(&field_name).unwrap();
+
+    let field_type = field_types.get(&field_ident).unwrap();
 
     let mut validators = vec![];
     let mut has_validate = false;
 
-    let find_struct_validator = |name: String, meta_items: &Vec<syn::NestedMetaItem>| -> Validator {
-        match name.as_ref() {
-            "length" => {
-                let mut min = None;
-                let mut max = None;
-                let mut equal = None;
-
-                for meta_item in meta_items {
-                    match *meta_item {
-                        syn::NestedMetaItem::MetaItem(ref item) => match *item {
-                            syn::MetaItem::NameValue(ref name, ref val) => {
-                                match name.to_string().as_ref() {
-                                    "min" => {
-                                        min = match lit_to_int(val) {
-                                            Some(s) => Some(s),
-                                            None => error("invalid argument type for `min` of `length` validator: only integers are allowed"),
-                                        };
-                                    },
-                                    "max" => {
-                                        max = match lit_to_int(val) {
-                                            Some(s) => Some(s),
-                                            None => error("invalid argument type for `max` of `length` validator: only integers are allowed"),
-                                        };
-                                    },
-                                    "equal" => {
-                                        equal = match lit_to_int(val) {
-                                            Some(s) => Some(s),
-                                            None => error("invalid argument type for `equal` of `length` validator: only integers are allowed"),
-                                        };
-                                    },
-                                    _ => error(&format!(
-                                        "unknown argument `{}` for validator `length` (it only has `min`, `max`, `equal`)",
-                                        name.to_string()
-                                    ))
-                                }
-                            },
-                            _ => panic!("unexpected item {:?} while parsing `length` validator", item)
-                        },
-                        _=> unreachable!()
-                    }
-                }
-                if equal.is_some() && (min.is_some() || max.is_some()) {
-                    error("both `equal` and `min` or `max` have been set in `length` validator: probably a mistake");
-                }
-                Validator::Length { min: min, max: max, equal: equal }
-            },
-            "range" => {
-                let mut min = 0.0;
-                let mut max = 0.0;
-                for meta_item in meta_items {
-                    match *meta_item {
-                        syn::NestedMetaItem::MetaItem(ref item) => match *item {
-                            syn::MetaItem::NameValue(ref name, ref val) => {
-                                match name.to_string().as_ref() {
-                                    "min" => {
-                                        min = match lit_to_float(val) {
-                                            Some(s) => s,
-                                            None => error("invalid argument type for `min` of `range` validator: only integers are allowed")
-                                        };
-                                    },
-                                    "max" => {
-                                        max = match lit_to_float(val) {
-                                            Some(s) => s,
-                                            None => error("invalid argument type for `max` of `range` validator: only integers are allowed")
-                                        };
-                                    },
-                                    _ => error(&format!(
-                                        "unknown argument `{}` for validator `range` (it only has `min`, `max`)",
-                                        name.to_string()
-                                    ))
-                                }
-                            },
-                            _ => panic!("unexpected item {:?} while parsing `range` validator", item)
-                        },
-                        _=> unreachable!()
-                    }
-                }
-
-                Validator::Range { min: min, max: max}
-            }
-            _ => panic!("unexpected list validator: {:?}", name)
-        }
-    };
-
     for attr in &field.attrs {
         if attr.name() != "validate" && attr.name() != "serde" {
             continue;
@@ -523,11 +244,11 @@ fn find_validators_for_field(field: &syn::Field, field_types: &HashMap<String, S
 
         match attr.value {
             syn::MetaItem::List(_, ref meta_items) => {
+                // original name before serde rename
                 if attr.name() == "serde" {
-                    match find_original_field_name(meta_items) {
-                        Some(s) => { field_name = s },
-                        None => ()
-                    };
+                    if let Some(s) = find_original_field_name(meta_items) {
+                        field_ident = s;
+                    }
                     continue;
                 }
 
@@ -538,58 +259,41 @@ fn find_validators_for_field(field: &syn::Field, field_types: &HashMap<String, S
                             // email, url
                             syn::MetaItem::Word(ref name) => match name.to_string().as_ref() {
                                 "email" => {
-                                    if field_type != "String"
-                                        && field_type != "&str"
-                                        && field_type != "Option<String>"
-                                        && !(field_type.starts_with("Option<") && field_type.ends_with("str>")) {
-                                        panic!("`email` validator can only be used on String or &str");
-                                    }
-                                    validators.push(Validator::Email);
+                                    assert_string_type("email", field_type);
+                                    validators.push(FieldValidation::new(Validator::Email));
                                 },
                                 "url" => {
-                                    if field_type != "String"
-                                        && field_type != "&str"
-                                        && field_type != "Option<String>"
-                                        && !(field_type.starts_with("Option<") && field_type.ends_with("str>")) {
-                                        panic!("`url` validator can only be used on String or &str");
-                                    }
-                                    validators.push(Validator::Url);
+                                    assert_string_type("url", field_type);
+                                    validators.push(FieldValidation::new(Validator::Url));
                                 },
-                                _ => panic!("Unexpected word validator: {}", name)
+                                _ => panic!("Unexpected validator: {}", name)
                             },
-                            // custom, contains, must_match
+                            // custom, contains, must_match, regex
                             syn::MetaItem::NameValue(ref name, ref val) => {
                                 match name.to_string().as_ref() {
                                     "custom" => {
                                         match lit_to_string(val) {
-                                            Some(s) => validators.push(Validator::Custom(s)),
+                                            Some(s) => validators.push(FieldValidation::new(Validator::Custom(s))),
                                             None => error("invalid argument for `custom` validator: only strings are allowed"),
                                         };
                                     },
                                     "contains" => {
                                         match lit_to_string(val) {
-                                            Some(s) => validators.push(Validator::Contains(s)),
+                                            Some(s) => validators.push(FieldValidation::new(Validator::Contains(s))),
                                             None => error("invalid argument for `contains` validator: only strings are allowed"),
                                         };
                                     },
                                     "regex" => {
                                         match lit_to_string(val) {
-                                            Some(s) => validators.push(Validator::Regex(s)),
+                                            Some(s) => validators.push(FieldValidation::new(Validator::Regex(s))),
                                             None => error("invalid argument for `regex` validator: only strings are allowed"),
                                         };
                                     }
                                     "must_match" => {
                                         match lit_to_string(val) {
                                             Some(s) => {
-                                                if let Some(t2) = field_types.get(&s) {
-                                                    if field_type == t2 {
-                                                        validators.push(Validator::MustMatch(s));
-                                                    } else {
-                                                        error("invalid argument for `must_match` validator: types of field can't match");
-                                                    }
-                                                } else {
-                                                    error("invalid argument for `must_match` validator: field doesn't exist in struct");
-                                                }
+                                                assert_type_matches(rust_ident.clone(), field_type, field_types.get(&s));
+                                                validators.push(FieldValidation::new(Validator::MustMatch(s)));
                                             },
                                             None => error("invalid argument for `must_match` validator: only strings are allowed"),
                                         };
@@ -597,49 +301,43 @@ fn find_validators_for_field(field: &syn::Field, field_types: &HashMap<String, S
                                     _ => panic!("unexpected name value validator: {:?}", name),
                                 };
                             },
-                            // validators with args: length for example
-                            syn::MetaItem::List(ref name, ref meta_items) => {
-                                // Some sanity checking first
-                                if name == "length" {
-                                    if field_type != "String"
-                                        && !field_type.starts_with("Vec<")
-                                        && !field_type.starts_with("Option<Vec<")
-                                        && field_type != "Option<String>"
-                                        // a bit ugly
-                                        && !(field_type.starts_with("Option<") && field_type.ends_with("str>"))
-                                        && field_type != "&str" {
-                                        error(&format!(
-                                            "Validator `length` can only be used on types `String`, `&str` or `Vec` but found `{}`",
-                                            field_type
-                                        ));
-                                    }
-
-                                    if meta_items.len() == 0 {
-                                        error("Validator `length` requires at least 1 argument out of `min`, `max` and `equal`");
-                                    }
-                                }
-
-                                if name == "range" {
-                                    if !RANGE_TYPES.contains(&field_type.as_ref()) {
-                                        error(&format!(
-                                            "Validator `range` can only be used on number types but found `{}`",
-                                            field_type
-                                        ));
-                                    }
-
-                                    if meta_items.len() != 2 {
-                                        error("Validator `range` requires 2 arguments: `min` and `max`");
+                            // Validators with several args
+                            syn::MetaItem::List(ref name, ref meta_items) => match name.to_string().as_ref() {
+                                "length" => {
+                                    assert_has_len(rust_ident.clone(), field_type);
+                                    validators.push(extract_length_validation(rust_ident.clone(), meta_items));
+                                },
+                                "range" => {
+                                    assert_has_range(rust_ident.clone(), field_type);
+                                    validators.push(extract_range_validation(rust_ident.clone(), meta_items));
+                                },
+                                "email" | "url" => {
+                                    validators.push(extract_argless_validation(name.to_string(), rust_ident.clone(), meta_items));
+                                },
+                                "custom" => {
+                                    validators.push(extract_one_arg_validation("function", name.to_string(), rust_ident.clone(), meta_items));
+                                },
+                                "contains" => {
+                                    validators.push(extract_one_arg_validation("pattern", name.to_string(), rust_ident.clone(), meta_items));
+                                },
+                                "regex" => {
+                                    validators.push(extract_one_arg_validation("path", name.to_string(), rust_ident.clone(), meta_items));
+                                },
+                                "must_match" => {
+                                    let validation = extract_one_arg_validation("other", name.to_string(), rust_ident.clone(), meta_items);
+                                    if let Validator::MustMatch(ref t2) = validation.validator {
+                                        assert_type_matches(rust_ident.clone(), field_type, field_types.get(t2));
                                     }
-                                }
-
-                                validators.push(find_struct_validator(name.to_string(), meta_items));
+                                    validators.push(validation);
+                                },
+                                _ => panic!("unexpected list validator: {:?}", name.to_string())
                             },
                         },
                         _ => unreachable!("Found a non MetaItem while looking for validators")
                     };
                 }
             },
-            _ => unreachable!("Got something other than a list of attributes while checking field `{}`", field_name),
+            _ => unreachable!("Got something other than a list of attributes while checking field `{}`", field_ident),
         }
     }
 
@@ -647,14 +345,14 @@ fn find_validators_for_field(field: &syn::Field, field_types: &HashMap<String, S
         error("it needs at least one validator");
     }
 
-    (field_name, validators)
+    (field_ident, validators)
 }
 
 /// Serde can be used to rename fields on deserialization but most of the times
 /// we want the error on the original field.
 ///
 /// For example a JS frontend might send camelCase fields and Rust converts them to snake_case
-/// but we want to send the errors back to the frontend with the original name
+/// but we want to send the errors back with the original name
 fn find_original_field_name(meta_items: &Vec<syn::NestedMetaItem>) -> Option<String> {
     let mut original_name = None;
 
@@ -666,9 +364,7 @@ fn find_original_field_name(meta_items: &Vec<syn::NestedMetaItem>) -> Option<Str
                     if name == "rename" {
                         original_name = Some(lit_to_string(val).unwrap());
                     }
-
                 },
-                // length
                 syn::MetaItem::List(_, ref meta_items) => {
                     return find_original_field_name(meta_items);
                 }
@@ -684,61 +380,3 @@ fn find_original_field_name(meta_items: &Vec<syn::NestedMetaItem>) -> Option<Str
     original_name
 }
 
-
-fn lit_to_string(lit: &syn::Lit) -> Option<String> {
-    match *lit {
-        syn::Lit::Str(ref s, _) => Some(s.to_string()),
-        _ => None,
-    }
-}
-
-fn lit_to_int(lit: &syn::Lit) -> Option<u64> {
-    match *lit {
-        syn::Lit::Int(ref s, _) => Some(*s),
-        // TODO: remove when attr_literals is stable
-        syn::Lit::Str(ref s, _) => Some(s.parse::<u64>().unwrap()),
-        _ => None,
-    }
-}
-
-fn lit_to_float(lit: &syn::Lit) -> Option<f64> {
-    match *lit {
-        syn::Lit::Float(ref s, _) => Some(s.parse::<f64>().unwrap()),
-        syn::Lit::Int(ref s, _) => Some(*s as f64),
-        // TODO: remove when attr_literals is stable
-        syn::Lit::Str(ref s, _) => Some(s.parse::<f64>().unwrap()),
-        _ => None,
-    }
-}
-
-fn lit_to_bool(lit: &syn::Lit) -> Option<bool> {
-    match *lit {
-        syn::Lit::Bool(ref s) => Some(*s),
-        // TODO: remove when attr_literals is stable
-        syn::Lit::Str(ref s, _) => if s == "true" { Some(true) } else { Some(false) },
-        _ => None,
-    }
-}
-
-fn option_u64_to_tokens(opt: Option<u64>) -> quote::Tokens {
-    let mut tokens = quote::Tokens::new();
-    tokens.append("::");
-    tokens.append("std");
-    tokens.append("::");
-    tokens.append("option");
-    tokens.append("::");
-    tokens.append("Option");
-    tokens.append("::");
-    match opt {
-        Some(ref t) => {
-            tokens.append("Some");
-            tokens.append("(");
-            t.to_tokens(&mut tokens);
-            tokens.append(")");
-        }
-        None => {
-            tokens.append("None");
-        }
-    }
-    tokens
-}
diff --git a/validator_derive/src/lit.rs b/validator_derive/src/lit.rs
new file mode 100644
index 0000000..0753a17
--- /dev/null
+++ b/validator_derive/src/lit.rs
@@ -0,0 +1,61 @@
+use quote::{self, ToTokens};
+use syn;
+
+
+pub fn lit_to_string(lit: &syn::Lit) -> Option<String> {
+    match *lit {
+        syn::Lit::Str(ref s, _) => Some(s.to_string()),
+        _ => None,
+    }
+}
+
+pub fn lit_to_int(lit: &syn::Lit) -> Option<u64> {
+    match *lit {
+        syn::Lit::Int(ref s, _) => Some(*s),
+        // TODO: remove when attr_literals is stable
+        syn::Lit::Str(ref s, _) => Some(s.parse::<u64>().unwrap()),
+        _ => None,
+    }
+}
+
+pub fn lit_to_float(lit: &syn::Lit) -> Option<f64> {
+    match *lit {
+        syn::Lit::Float(ref s, _) => Some(s.parse::<f64>().unwrap()),
+        syn::Lit::Int(ref s, _) => Some(*s as f64),
+        // TODO: remove when attr_literals is stable
+        syn::Lit::Str(ref s, _) => Some(s.parse::<f64>().unwrap()),
+        _ => None,
+    }
+}
+
+pub fn lit_to_bool(lit: &syn::Lit) -> Option<bool> {
+    match *lit {
+        syn::Lit::Bool(ref s) => Some(*s),
+        // TODO: remove when attr_literals is stable
+        syn::Lit::Str(ref s, _) => if s == "true" { Some(true) } else { Some(false) },
+        _ => None,
+    }
+}
+
+pub fn option_u64_to_tokens(opt: Option<u64>) -> quote::Tokens {
+    let mut tokens = quote::Tokens::new();
+    tokens.append("::");
+    tokens.append("std");
+    tokens.append("::");
+    tokens.append("option");
+    tokens.append("::");
+    tokens.append("Option");
+    tokens.append("::");
+    match opt {
+        Some(ref t) => {
+            tokens.append("Some");
+            tokens.append("(");
+            t.to_tokens(&mut tokens);
+            tokens.append(")");
+        }
+        None => {
+            tokens.append("None");
+        }
+    }
+    tokens
+}
diff --git a/validator_derive/src/quoting.rs b/validator_derive/src/quoting.rs
new file mode 100644
index 0000000..69353e9
--- /dev/null
+++ b/validator_derive/src/quoting.rs
@@ -0,0 +1,332 @@
+use quote;
+use validator::Validator;
+use syn;
+
+use lit::option_u64_to_tokens;
+use validation::{FieldValidation, SchemaValidation};
+use asserts::NUMBER_TYPES;
+
+
+/// Pass around all the information needed for creating a validation
+#[derive(Debug)]
+pub struct FieldQuoter {
+    ident: syn::Ident,
+    /// The field name
+    name: String,
+    /// The field type
+    _type: String,
+}
+
+impl FieldQuoter {
+    pub fn new(ident: syn::Ident, name: String, _type: String) -> FieldQuoter {
+        FieldQuoter { ident, name, _type }
+    }
+
+    /// Don't put a & in front a pointer since we are going to pass
+    /// a reference to the validator
+    /// Also just use the ident without if it's optional and will go through
+    /// a if let first
+    pub fn quote_validator_param(&self) -> quote::Tokens {
+        let ident = &self.ident;
+
+        if self._type.starts_with("Option<") {
+            quote!(#ident)
+        } else if self._type.starts_with("&") || NUMBER_TYPES.contains(&self._type.as_ref()) {
+            quote!(self.#ident)
+        } else {
+            quote!(&self.#ident)
+        }
+    }
+
+    pub fn get_optional_validator_param(&self) -> quote::Tokens {
+        let ident = &self.ident;
+        if self._type.starts_with("Option<&") || NUMBER_TYPES.contains(&self._type.as_ref()) {
+          quote!(#ident)
+        } else {
+          quote!(ref #ident)
+        }
+    }
+
+    /// Wrap the quoted output of a validation with a if let Some if
+    /// the field type is an option
+    pub fn wrap_if_option(&self, tokens: quote::Tokens) -> quote::Tokens {
+        let field_ident = &self.ident;
+        let optional_pattern_matched = self.get_optional_validator_param();
+        if self._type.starts_with("Option<") {
+            return quote!(
+                if let Some(#optional_pattern_matched) = self.#field_ident {
+                    #tokens
+                }
+            )
+        }
+
+        tokens
+    }
+}
+
+/// Quote an actual end-user error creation automatically
+fn quote_error(validation: &FieldValidation) -> quote::Tokens {
+    let code = &validation.code;
+    let add_message_quoted = if let Some(ref m) = validation.message {
+        quote!(err.message = Some(::std::borrow::Cow::from(#m));)
+    } else {
+        quote!()
+    };
+
+    quote!(
+        let mut err = ::validator::ValidationError::new(#code);
+        #add_message_quoted
+    )
+}
+
+
+pub fn quote_length_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let field_name = &field_quoter.name;
+    let validator_param = field_quoter.quote_validator_param();
+
+    if let Validator::Length { min, max, equal } = validation.validator {
+        // Can't interpolate None
+        let min_tokens = option_u64_to_tokens(min);
+        let max_tokens = option_u64_to_tokens(max);
+        let equal_tokens = option_u64_to_tokens(equal);
+
+        let min_err_param_quoted = if let Some(v) = min {
+            quote!(err.add_param(::std::borrow::Cow::from("min"), &#v);)
+        } else {
+            quote!()
+        };
+        let max_err_param_quoted = if let Some(v) = max {
+            quote!(err.add_param(::std::borrow::Cow::from("max"), &#v);)
+        } else {
+            quote!()
+        };
+        let equal_err_param_quoted = if let Some(v) = equal {
+            quote!(err.add_param(::std::borrow::Cow::from("equal"), &#v);)
+        } else {
+            quote!()
+        };
+
+        let quoted_error = quote_error(&validation);
+        let quoted = quote!(
+            if !::validator::validate_length(
+                ::validator::Validator::Length {
+                    min: #min_tokens,
+                    max: #max_tokens,
+                    equal: #equal_tokens
+                },
+                #validator_param
+            ) {
+                #quoted_error
+                #min_err_param_quoted
+                #max_err_param_quoted
+                #equal_err_param_quoted
+                err.add_param(::std::borrow::Cow::from("value"), &#validator_param);
+                errors.add(#field_name, err);
+            }
+        );
+
+        return field_quoter.wrap_if_option(quoted);
+    }
+
+    unreachable!()
+}
+
+pub fn quote_range_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let field_name = &field_quoter.name;
+    let quoted_ident = field_quoter.quote_validator_param();
+
+    if let Validator::Range { min, max } = validation.validator {
+        let quoted_error = quote_error(&validation);
+        let min_err_param_quoted = quote!(err.add_param(::std::borrow::Cow::from("min"), &#min););
+        let max_err_param_quoted = quote!(err.add_param(::std::borrow::Cow::from("max"), &#max););
+        let quoted = quote!(
+            if !::validator::validate_range(
+                ::validator::Validator::Range {min: #min, max: #max},
+                #quoted_ident as f64
+            ) {
+                #quoted_error
+                #min_err_param_quoted
+                #max_err_param_quoted
+                err.add_param(::std::borrow::Cow::from("value"), &#quoted_ident);
+                errors.add(#field_name, err);
+            }
+        );
+
+        return field_quoter.wrap_if_option(quoted);
+    }
+
+    unreachable!()
+}
+
+pub fn quote_url_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let field_name = &field_quoter.name;
+    let validator_param = field_quoter.quote_validator_param();
+
+    let quoted_error = quote_error(&validation);
+    let quoted = quote!(
+        if !::validator::validate_url(#validator_param) {
+            #quoted_error
+            err.add_param(::std::borrow::Cow::from("value"), &#validator_param);
+            errors.add(#field_name, err);
+        }
+    );
+
+    field_quoter.wrap_if_option(quoted)
+}
+
+pub fn quote_email_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let field_name = &field_quoter.name;
+    let validator_param = field_quoter.quote_validator_param();
+
+    let quoted_error = quote_error(&validation);
+    let quoted = quote!(
+        if !::validator::validate_email(#validator_param) {
+            #quoted_error
+            err.add_param(::std::borrow::Cow::from("value"), &#validator_param);
+            errors.add(#field_name, err);
+        }
+    );
+
+    field_quoter.wrap_if_option(quoted)
+}
+
+pub fn quote_must_match_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let ident = &field_quoter.ident;
+    let field_name = &field_quoter.name;
+
+    if let Validator::MustMatch(ref other) = validation.validator {
+        let other_ident = syn::Ident::new(other.clone());
+        let quoted_error = quote_error(&validation);
+        let quoted = quote!(
+            if !::validator::validate_must_match(&self.#ident, &self.#other_ident) {
+                #quoted_error
+                err.add_param(::std::borrow::Cow::from("value"), &self.#ident);
+                err.add_param(::std::borrow::Cow::from("other"), &self.#other_ident);
+                errors.add(#field_name, err);
+            }
+        );
+
+        return field_quoter.wrap_if_option(quoted);
+    }
+
+    unreachable!();
+}
+
+pub fn quote_custom_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let field_name = &field_quoter.name;
+    let validator_param = field_quoter.quote_validator_param();
+
+    if let Validator::Custom(ref fun) = validation.validator {
+        let fn_ident = syn::Ident::new(fun.clone());
+        let add_message_quoted = if let Some(ref m) = validation.message {
+            quote!(err.message = Some(::std::borrow::Cow::from(#m));)
+        } else {
+            quote!()
+        };
+
+        let quoted = quote!(
+            match #fn_ident(#validator_param) {
+                ::std::result::Result::Ok(()) => (),
+                ::std::result::Result::Err(mut err) => {
+                    #add_message_quoted
+                    err.add_param(::std::borrow::Cow::from("value"), &#validator_param);
+                    errors.add(#field_name, err);
+                },
+            };
+        );
+
+        return field_quoter.wrap_if_option(quoted);
+    }
+
+    unreachable!();
+}
+
+pub fn quote_contains_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let field_name = &field_quoter.name;
+    let validator_param = field_quoter.quote_validator_param();
+
+    if let Validator::Contains(ref needle) = validation.validator {
+        let quoted_error = quote_error(&validation);
+        let quoted = quote!(
+            if !::validator::validate_contains(#validator_param, &#needle) {
+                #quoted_error
+                err.add_param(::std::borrow::Cow::from("value"), &#validator_param);
+                err.add_param(::std::borrow::Cow::from("needle"), &#needle);
+                errors.add(#field_name, err);
+            }
+        );
+
+        return field_quoter.wrap_if_option(quoted);
+    }
+
+    unreachable!();
+}
+
+pub fn quote_regex_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    let field_name = &field_quoter.name;
+    let validator_param = field_quoter.quote_validator_param();
+
+    if let Validator::Regex(ref re) = validation.validator {
+        let re_ident = syn::Ident::new(re.clone());
+        let quoted_error = quote_error(&validation);
+        let quoted = quote!(
+            if !#re_ident.is_match(#validator_param) {
+                #quoted_error
+                err.add_param(::std::borrow::Cow::from("value"), &#validator_param);
+                errors.add(#field_name, err);
+            }
+        );
+
+        return field_quoter.wrap_if_option(quoted);
+    }
+
+    unreachable!();
+}
+
+pub fn quote_field_validation(field_quoter: &FieldQuoter, validation: &FieldValidation) -> quote::Tokens {
+    match validation.validator {
+        Validator::Length {..} => quote_length_validation(&field_quoter, validation),
+        Validator::Range {..} => quote_range_validation(&field_quoter, validation),
+        Validator::Email => quote_email_validation(&field_quoter, validation),
+        Validator::Url => quote_url_validation(&field_quoter, validation),
+        Validator::MustMatch(_) => quote_must_match_validation(&field_quoter, validation),
+        Validator::Custom(_) => quote_custom_validation(&field_quoter, validation),
+        Validator::Contains(_) => quote_contains_validation(&field_quoter, validation),
+        Validator::Regex(_) => quote_regex_validation(&field_quoter, validation),
+    }
+}
+
+
+pub fn quote_schema_validation(validation: Option<SchemaValidation>) -> quote::Tokens {
+    if let Some(v) = validation {
+        let fn_ident = syn::Ident::new(v.function);
+
+        let add_message_quoted = if let Some(ref m) = v.message {
+            quote!(err.message = Some(::std::borrow::Cow::from(#m));)
+        } else {
+            quote!()
+        };
+        let mut_err_token = if v.message.is_some() { quote!(mut) } else { quote!() };
+        let quoted = quote!(
+            match #fn_ident(self) {
+                ::std::result::Result::Ok(()) => (),
+                ::std::result::Result::Err(#mut_err_token err) => {
+                    #add_message_quoted
+                    errors.add("__all__", err);
+                },
+            };
+        );
+
+        if !v.skip_on_field_errors {
+            return quoted;
+        }
+
+        quote!(
+            if errors.is_empty() {
+                #quoted
+            }
+        )
+    } else {
+        quote!()
+    }
+}
diff --git a/validator_derive/src/validation.rs b/validator_derive/src/validation.rs
new file mode 100644
index 0000000..a3350da
--- /dev/null
+++ b/validator_derive/src/validation.rs
@@ -0,0 +1,290 @@
+use syn;
+
+use validator::Validator;
+
+use lit::*;
+
+
+#[derive(Debug)]
+pub struct SchemaValidation {
+    pub function: String,
+    pub skip_on_field_errors: bool,
+    pub code: Option<String>,
+    pub message: Option<String>,
+}
+
+
+#[derive(Debug)]
+pub struct FieldValidation {
+    pub code: String,
+    pub message: Option<String>,
+    pub validator: Validator,
+}
+
+impl FieldValidation {
+    pub fn new(validator: Validator) -> FieldValidation {
+        FieldValidation {
+            code: validator.code().to_string(),
+            validator,
+            message: None,
+        }
+    }
+}
+
+pub fn extract_length_validation(field: String, meta_items: &Vec<syn::NestedMetaItem>) -> FieldValidation {
+    let mut min = None;
+    let mut max = None;
+    let mut equal = None;
+
+    let mut code = None;
+    let mut message = None;
+
+    let error = |msg: &str| -> ! {
+        panic!("Invalid attribute #[validate] on field `{}`: {}", field, msg);
+    };
+
+    for meta_item in meta_items {
+        if let syn::NestedMetaItem::MetaItem(ref item) = *meta_item {
+            if let syn::MetaItem::NameValue(ref name, ref val) = *item {
+                match name.to_string().as_ref() {
+                    "min" => {
+                        min = match lit_to_int(val) {
+                            Some(s) => Some(s),
+                            None => error("invalid argument type for `min` of `length` validator: only integers are allowed"),
+                        };
+                    },
+                    "max" => {
+                        max = match lit_to_int(val) {
+                            Some(s) => Some(s),
+                            None => error("invalid argument type for `max` of `length` validator: only integers are allowed"),
+                        };
+                    },
+                    "equal" => {
+                        equal = match lit_to_int(val) {
+                            Some(s) => Some(s),
+                            None => error("invalid argument type for `equal` of `length` validator: only integers are allowed"),
+                        };
+                    },
+                    "code" => {
+                        code = match lit_to_string(val) {
+                            Some(s) => Some(s),
+                            None => error("invalid argument type for `code` of `length` validator: only a string is allowed"),
+                        };
+                    },
+                    "message" => {
+                        message = match lit_to_string(val) {
+                            Some(s) => Some(s),
+                            None => error("invalid argument type for `message` of `length` validator: only a string is allowed"),
+                        };
+                    },
+                    _ => error(&format!(
+                        "unknown argument `{}` for validator `length` (it only has `min`, `max`, `equal`)",
+                        name.to_string()
+                    ))
+                }
+            } else {
+                panic!("unexpected item {:?} while parsing `length` validator of field {}", item, field)
+            }
+        }
+    }
+
+    if equal.is_some() && (min.is_some() || max.is_some()) {
+        error("both `equal` and `min` or `max` have been set in `length` validator: probably a mistake");
+    }
+    if min.is_none() && max.is_none() && equal.is_none() {
+        error("Validator `length` requires at least 1 argument out of `min`, `max` and `equal`");
+    }
+
+    let validator = Validator::Length { min, max, equal };
+    FieldValidation {
+        message,
+        code: code.unwrap_or_else(|| validator.code().to_string()),
+        validator,
+    }
+}
+
+pub fn extract_range_validation(field: String, meta_items: &Vec<syn::NestedMetaItem>) -> FieldValidation {
+    let mut min = 0.0;
+    let mut max = 0.0;
+
+    let mut code = None;
+    let mut message = None;
+
+    let error = |msg: &str| -> ! {
+        panic!("Invalid attribute #[validate] on field `{}`: {}", field, msg);
+    };
+
+    // whether it has both `min` and `max`
+    let mut has_min = false;
+    let mut has_max = false;
+
+    for meta_item in meta_items {
+        match *meta_item {
+            syn::NestedMetaItem::MetaItem(ref item) => match *item {
+                syn::MetaItem::NameValue(ref name, ref val) => {
+                    match name.to_string().as_ref() {
+                        "min" => {
+                            min = match lit_to_float(val) {
+                                Some(s) => s,
+                                None => error("invalid argument type for `min` of `range` validator: only integers are allowed")
+                            };
+                            has_min = true;
+                        },
+                        "max" => {
+                            max = match lit_to_float(val) {
+                                Some(s) => s,
+                                None => error("invalid argument type for `max` of `range` validator: only integers are allowed")
+                            };
+                            has_max = true;
+                        },
+                        "code" => {
+                            code = match lit_to_string(val) {
+                                Some(s) => Some(s),
+                                None => error("invalid argument type for `code` of `length` validator: only a string is allowed"),
+                            };
+                        },
+                        "message" => {
+                            message = match lit_to_string(val) {
+                                Some(s) => Some(s),
+                                None => error("invalid argument type for `message` of `length` validator: only a string is allowed"),
+                            };
+                        },
+                        _ => error(&format!(
+                            "unknown argument `{}` for validator `range` (it only has `min`, `max`)",
+                            name.to_string()
+                        ))
+                    }
+                },
+                _ => panic!("unexpected item {:?} while parsing `range` validator", item)
+            },
+            _=> unreachable!()
+        }
+    }
+
+    if !has_min || !has_max {
+        error("Validator `range` requires 2 arguments: `min` and `max`");
+    }
+
+    let validator = Validator::Range { min, max };
+    FieldValidation {
+        message,
+        code: code.unwrap_or_else(|| validator.code().to_string()),
+        validator,
+    }
+}
+
+/// Extract url/email field validation with a code or a message
+pub fn extract_argless_validation(validator_name: String, field: String, meta_items: &Vec<syn::NestedMetaItem>) -> FieldValidation {
+    let mut code = None;
+    let mut message = None;
+
+    for meta_item in meta_items {
+        match *meta_item {
+            syn::NestedMetaItem::MetaItem(ref item) => match *item {
+                syn::MetaItem::NameValue(ref name, ref val) => {
+                    match name.to_string().as_ref() {
+                        "code" => {
+                            code = match lit_to_string(val) {
+                                Some(s) => Some(s),
+                                None => panic!(
+                                    "Invalid argument type for `code` for validator `{}` on field `{}`: only a string is allowed",
+                                    validator_name, field
+                                ),
+                            };
+                        },
+                        "message" => {
+                            message = match lit_to_string(val) {
+                                Some(s) => Some(s),
+                                None => panic!(
+                                    "Invalid argument type for `message` for validator `{}` on field `{}`: only a string is allowed",
+                                    validator_name, field
+                                ),
+                            };
+                        },
+                        _ => panic!(
+                            "Unknown argument `{}` for validator `{}` on field `{}`",
+                            name.to_string(), validator_name, field
+                        )
+                    }
+                },
+                _ => panic!("unexpected item {:?} while parsing `range` validator", item)
+            },
+            _=> unreachable!()
+        }
+    }
+
+    let validator = if validator_name == "email" { Validator::Email } else { Validator::Url };
+    FieldValidation {
+        message,
+        code: code.unwrap_or_else(|| validator.code().to_string()),
+        validator,
+    }
+}
+
+/// For custom, contains, regex, must_match
+pub fn extract_one_arg_validation(val_name: &str, validator_name: String, field: String, meta_items: &Vec<syn::NestedMetaItem>) -> FieldValidation {
+    let mut code = None;
+    let mut message = None;
+    let mut value = None;
+
+    for meta_item in meta_items {
+        match *meta_item {
+            syn::NestedMetaItem::MetaItem(ref item) => match *item {
+                syn::MetaItem::NameValue(ref name, ref val) => {
+                    match name.to_string().as_ref() {
+                        v if v == val_name => {
+                            value = match lit_to_string(val) {
+                                Some(s) => Some(s),
+                                None => panic!(
+                                    "Invalid argument type for `{}` for validator `{}` on field `{}`: only a string is allowed",
+                                    val_name, validator_name, field
+                                ),
+                            };
+                        },
+                        "code" => {
+                            code = match lit_to_string(val) {
+                                Some(s) => Some(s),
+                                None => panic!(
+                                    "Invalid argument type for `code` for validator `{}` on field `{}`: only a string is allowed",
+                                    validator_name, field
+                                ),
+                            };
+                        },
+                        "message" => {
+                            message = match lit_to_string(val) {
+                                Some(s) => Some(s),
+                                None => panic!(
+                                    "Invalid argument type for `message` for validator `{}` on field `{}`: only a string is allowed",
+                                    validator_name, field
+                                ),
+                            };
+                        },
+                        _ => panic!(
+                            "Unknown argument `{}` for validator `{}` on field `{}`",
+                            name.to_string(), validator_name, field
+                        )
+                    }
+                },
+                _ => panic!("unexpected item {:?} while parsing `range` validator", item)
+            },
+            _=> unreachable!()
+        }
+    }
+
+    if value.is_none() {
+        panic!("Missing argument `{}` for validator `{}` on field `{}`", val_name, validator_name, field);
+    }
+
+    let validator = match validator_name.as_ref() {
+        "custom" => Validator::Custom(value.unwrap()),
+        "contains" => Validator::Contains(value.unwrap()),
+        "must_match" => Validator::MustMatch(value.unwrap()),
+        "regex" => Validator::Regex(value.unwrap()),
+        _ => unreachable!(),
+    };
+    FieldValidation {
+        message,
+        code: code.unwrap_or_else(|| validator.code().to_string()),
+        validator,
+    }
+}
diff --git a/validator_derive/tests/compile-fail/length/wrong_type.rs b/validator_derive/tests/compile-fail/length/wrong_type.rs
index 365675f..a9d53d4 100644
--- a/validator_derive/tests/compile-fail/length/wrong_type.rs
+++ b/validator_derive/tests/compile-fail/length/wrong_type.rs
@@ -4,7 +4,7 @@ use validator::Validate;
 
 #[derive(Validate)]
 //~^ ERROR: proc-macro derive panicked
-//~^^ HELP: Invalid attribute #[validate] on field `s`: Validator `length` can only be used on types `String`, `&str` or `Vec` but found `usize`
+//~^^ HELP: Validator `length` can only be used on types `String`, `&str` or `Vec` but found `usize`
 struct Test {
     #[validate(length())]
     s: usize,
diff --git a/validator_derive/tests/compile-fail/must_match/field_doesnt_exist.rs b/validator_derive/tests/compile-fail/must_match/field_doesnt_exist.rs
index f3a2347..1ba5319 100644
--- a/validator_derive/tests/compile-fail/must_match/field_doesnt_exist.rs
+++ b/validator_derive/tests/compile-fail/must_match/field_doesnt_exist.rs
@@ -4,7 +4,7 @@ use validator::Validate;
 
 #[derive(Validate)]
 //~^ ERROR: proc-macro derive panicked
-//~^^ HELP: Invalid attribute #[validate] on field `password`: invalid argument for `must_match` validator: field doesn't exist in struct
+//~^^ HELP: Invalid argument for `must_match` validator of field `password`: the other field doesn't exist in struct
 struct Test {
     #[validate(must_match = "password2")]
     password: String,
diff --git a/validator_derive/tests/compile-fail/must_match/field_type_doesnt_match.rs b/validator_derive/tests/compile-fail/must_match/field_type_doesnt_match.rs
index b04a732..580495a 100644
--- a/validator_derive/tests/compile-fail/must_match/field_type_doesnt_match.rs
+++ b/validator_derive/tests/compile-fail/must_match/field_type_doesnt_match.rs
@@ -4,7 +4,7 @@ use validator::Validate;
 
 #[derive(Validate)]
 //~^ ERROR: proc-macro derive panicked
-//~^^ HELP: Invalid attribute #[validate] on field `password`: invalid argument for `must_match` validator: types of field can't match
+//~^^ HELP: Invalid argument for `must_match` validator of field `password`: types of field can't match
 struct Test {
     #[validate(must_match = "password2")]
     password: String,
diff --git a/validator_derive/tests/compile-fail/range/wrong_type.rs b/validator_derive/tests/compile-fail/range/wrong_type.rs
index 239a93d..f6a0a43 100644
--- a/validator_derive/tests/compile-fail/range/wrong_type.rs
+++ b/validator_derive/tests/compile-fail/range/wrong_type.rs
@@ -6,7 +6,7 @@ use validator::Validate;
 
 #[derive(Validate)]
 //~^ ERROR: proc-macro derive panicked
-//~^^ HELP: Invalid attribute #[validate] on field `s`: Validator `range` can only be used on number types but found `String`
+//~^^ HELP: Validator `range` can only be used on number types but found `String`
 struct Test {
     #[validate(range(min = 10.0, max = 12.0))]
     s: String,
diff --git a/validator_derive/tests/complex.rs b/validator_derive/tests/complex.rs
new file mode 100644
index 0000000..db5f1bf
--- /dev/null
+++ b/validator_derive/tests/complex.rs
@@ -0,0 +1,155 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+#[macro_use]
+extern crate serde_derive;
+extern crate serde_json;
+extern crate regex;
+#[macro_use]
+extern crate lazy_static;
+
+use regex::Regex;
+use validator::{Validate, ValidationError};
+
+
+fn validate_unique_username(username: &str) -> Result<(), ValidationError> {
+    if username == "xXxShad0wxXx" {
+        return Err(ValidationError::new("terrible_username"));
+    }
+
+    Ok(())
+}
+
+fn validate_signup(data: &SignupData) -> Result<(), ValidationError> {
+    if data.mail.ends_with("gmail.com") && data.age == 18 {
+        return Err(ValidationError::new("stupid_rule"));
+    }
+
+    Ok(())
+}
+
+#[derive(Debug, Validate, Deserialize)]
+#[validate(schema(function = "validate_signup", skip_on_field_errors = "false"))]
+struct SignupData {
+    #[validate(email)]
+    mail: String,
+    #[validate(url)]
+    site: String,
+    #[validate(length(min = "1"), custom = "validate_unique_username")]
+    #[serde(rename = "firstName")]
+    first_name: String,
+    #[validate(range(min = "18", max = "20"))]
+    age: u32,
+}
+
+
+#[test]
+fn is_fine_with_many_valid_validations() {
+    let signup = SignupData {
+        mail: "bob@bob.com".to_string(),
+        site: "http://hello.com".to_string(),
+        first_name: "Bob".to_string(),
+        age: 18,
+    };
+
+    assert!(signup.validate().is_ok());
+}
+
+#[test]
+fn failed_validation_points_to_original_field_name() {
+    let signup = SignupData {
+        mail: "bob@bob.com".to_string(),
+        site: "http://hello.com".to_string(),
+        first_name: "".to_string(),
+        age: 18,
+    };
+    let res = signup.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("firstName"));
+    assert_eq!(errs["firstName"].len(), 1);
+    assert_eq!(errs["firstName"][0].code, "length");
+}
+
+#[test]
+fn test_can_validate_option_fields_with_lifetime() {
+    lazy_static! {
+        static ref RE2: Regex = Regex::new(r"[a-z]{2}").unwrap();
+    }
+
+    #[derive(Debug, Validate)]
+    struct PutStruct<'a> {
+        #[validate(length(min = "1", max = "10"))]
+        name: Option<&'a str>,
+        #[validate(range(min = "1", max = "10"))]
+        range: Option<usize>,
+        #[validate(email)]
+        email: Option<&'a str>,
+        #[validate(url)]
+        url: Option<&'a str>,
+        #[validate(contains = "@")]
+        text: Option<&'a str>,
+        #[validate(regex = "RE2")]
+        re: Option<&'a str>,
+        #[validate(custom = "check_str")]
+        custom: Option<&'a str>,
+    }
+
+    fn check_str(_: &str) -> Result<(), ValidationError> {
+        Ok(())
+    }
+
+    let s = PutStruct {
+        name: Some("al"),
+        range: Some(2),
+        email: Some("hi@gmail.com"),
+        url: Some("http://google.com"),
+        text: Some("@someone"),
+        re: Some("hi"),
+        custom: Some("hey"),
+    };
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn test_can_validate_option_fields_without_lifetime() {
+    lazy_static! {
+        static ref RE2: Regex = Regex::new(r"[a-z]{2}").unwrap();
+    }
+
+    #[derive(Debug, Validate)]
+    struct PutStruct {
+        #[validate(length(min = "1", max = "10"))]
+        name: Option<String>,
+        #[validate(length(min = "1", max = "10"))]
+        ids: Option<Vec<usize>>,
+        #[validate(range(min = "1", max = "10"))]
+        range: Option<usize>,
+        #[validate(email)]
+        email: Option<String>,
+        #[validate(url)]
+        url: Option<String>,
+        #[validate(contains = "@")]
+        text: Option<String>,
+        #[validate(regex = "RE2")]
+        re: Option<String>,
+        #[validate(custom = "check_str")]
+        custom: Option<String>,
+    }
+
+    fn check_str(_: &str) -> Result<(), ValidationError> {
+        Ok(())
+    }
+
+    let s = PutStruct {
+        name: Some("al".to_string()),
+        ids: Some(vec![1, 2, 3]),
+        range: Some(2),
+        email: Some("hi@gmail.com".to_string()),
+        url: Some("http://google.com".to_string()),
+        text: Some("@someone".to_string()),
+        re: Some("hi".to_string()),
+        custom: Some("hey".to_string()),
+    };
+    assert!(s.validate().is_ok());
+}
diff --git a/validator_derive/tests/contains.rs b/validator_derive/tests/contains.rs
new file mode 100644
index 0000000..847de0f
--- /dev/null
+++ b/validator_derive/tests/contains.rs
@@ -0,0 +1,77 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::Validate;
+
+#[test]
+fn can_validate_contains_ok() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(contains = "he")]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "hello".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn value_not_containing_needle_fails_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(contains = "he")]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "contains");
+    assert_eq!(errs["val"][0].params["value"], "");
+    assert_eq!(errs["val"][0].params["needle"], "he");
+}
+
+#[test]
+fn can_specify_code_for_contains() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(contains(pattern = "he", code = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "oops");
+}
+
+#[test]
+fn can_specify_message_for_contains() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(contains(pattern = "he", message = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
diff --git a/validator_derive/tests/custom.rs b/validator_derive/tests/custom.rs
new file mode 100644
index 0000000..0cac75f
--- /dev/null
+++ b/validator_derive/tests/custom.rs
@@ -0,0 +1,66 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::{Validate, ValidationError};
+
+fn valid_custom_fn(_: &str) -> Result<(), ValidationError> {
+    Ok(())
+}
+
+fn invalid_custom_fn(_: &str) -> Result<(), ValidationError> {
+    Err(ValidationError::new("meh"))
+}
+
+#[test]
+fn can_validate_custom_fn_ok() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(custom = "valid_custom_fn")]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "hello".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn can_fail_custom_fn_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(custom = "invalid_custom_fn")]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "meh");
+    assert_eq!(errs["val"][0].params["value"], "");
+}
+
+#[test]
+fn can_specify_message_for_custom_fn() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(custom(function = "invalid_custom_fn", message = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
diff --git a/validator_derive/tests/email.rs b/validator_derive/tests/email.rs
new file mode 100644
index 0000000..fc05bf9
--- /dev/null
+++ b/validator_derive/tests/email.rs
@@ -0,0 +1,77 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::Validate;
+
+
+#[test]
+fn can_validate_valid_email() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(email)]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "bob@bob.com".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn bad_email_fails_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(email)]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "bob".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "email");
+    assert_eq!(errs["val"][0].params["value"], "bob");
+}
+
+#[test]
+fn can_specify_code_for_email() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(email(code = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: "bob".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "oops");
+}
+
+#[test]
+fn can_specify_message_for_email() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(email(message = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: "bob".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
diff --git a/validator_derive/tests/length.rs b/validator_derive/tests/length.rs
new file mode 100644
index 0000000..892cf74
--- /dev/null
+++ b/validator_derive/tests/length.rs
@@ -0,0 +1,78 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::Validate;
+
+#[test]
+fn can_validate_length_ok() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(length(min = "5", max = "10"))]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "hello".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn value_out_of_length_fails_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(length(min = "5", max = "10"))]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "length");
+    assert_eq!(errs["val"][0].params["value"], "");
+    assert_eq!(errs["val"][0].params["min"], 5);
+    assert_eq!(errs["val"][0].params["max"], 10);
+}
+
+#[test]
+fn can_specify_code_for_length() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(length(min = "5", max = "10", code = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "oops");
+}
+
+#[test]
+fn can_specify_message_for_length() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(length(min = "5", max = "10", message = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
diff --git a/validator_derive/tests/must_match.rs b/validator_derive/tests/must_match.rs
new file mode 100644
index 0000000..038616a
--- /dev/null
+++ b/validator_derive/tests/must_match.rs
@@ -0,0 +1,87 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::Validate;
+
+
+#[test]
+fn can_validate_valid_must_match() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(must_match = "val2")]
+        val: String,
+        val2: String,
+    }
+
+    let s = TestStruct {
+        val: "bob".to_string(),
+        val2: "bob".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn not_matching_fails_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(must_match = "val2")]
+        val: String,
+        val2: String,
+    }
+
+    let s = TestStruct {
+        val: "bob".to_string(),
+        val2: "bobby".to_string(),
+    };
+
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "must_match");
+    assert_eq!(errs["val"][0].params["value"], "bob");
+    assert_eq!(errs["val"][0].params["other"], "bobby");
+}
+
+#[test]
+fn can_specify_code_for_must_match() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(must_match(other = "val2", code = "oops"))]
+        val: String,
+        val2: String,
+    }
+    let s = TestStruct {
+        val: "bob".to_string(),
+        val2: "bobb".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "oops");
+}
+
+#[test]
+fn can_specify_message_for_must_match() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(must_match(other = "val2", message = "oops"))]
+        val: String,
+        val2: String,
+    }
+    let s = TestStruct {
+        val: "bob".to_string(),
+        val2: "bobb".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
diff --git a/validator_derive/tests/range.rs b/validator_derive/tests/range.rs
new file mode 100644
index 0000000..2ecd678
--- /dev/null
+++ b/validator_derive/tests/range.rs
@@ -0,0 +1,78 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::Validate;
+
+#[test]
+fn can_validate_range_ok() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(range(min = "5", max = "10"))]
+        val: usize,
+    }
+
+    let s = TestStruct {
+        val: 6,
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn value_out_of_range_fails_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(range(min = "5", max = "10"))]
+        val: usize,
+    }
+
+    let s = TestStruct {
+        val: 11,
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "range");
+}
+
+#[test]
+fn can_specify_code_for_range() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(range(min = "5", max = "10", code = "oops"))]
+        val: usize,
+    }
+    let s = TestStruct {
+        val: 11,
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "oops");
+    assert_eq!(errs["val"][0].params["value"], 11);
+    assert_eq!(errs["val"][0].params["min"], 5f64);
+    assert_eq!(errs["val"][0].params["max"], 10f64);
+}
+
+#[test]
+fn can_specify_message_for_range() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(range(min = "5", max = "10", message = "oops"))]
+        val: usize,
+    }
+    let s = TestStruct {
+        val: 1,
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
diff --git a/validator_derive/tests/regex.rs b/validator_derive/tests/regex.rs
new file mode 100644
index 0000000..58f8f69
--- /dev/null
+++ b/validator_derive/tests/regex.rs
@@ -0,0 +1,84 @@
+extern crate regex;
+#[macro_use]
+extern crate lazy_static;
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::Validate;
+use regex::Regex;
+
+lazy_static! {
+    static ref RE2: Regex = Regex::new(r"^[a-z]{2}$").unwrap();
+}
+
+#[test]
+fn can_validate_valid_regex() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(regex = "RE2")]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "aa".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn bad_value_for_regex_fails_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(regex = "RE2")]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "2".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "regex");
+    assert_eq!(errs["val"][0].params["value"], "2");
+}
+
+#[test]
+fn can_specify_code_for_regex() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(regex(path = "RE2", code = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: "2".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "oops");
+}
+
+#[test]
+fn can_specify_message_for_regex() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(regex(path = "RE2", message = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: "2".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
diff --git a/validator_derive/tests/run-pass/custom.rs b/validator_derive/tests/run-pass/custom.rs
index 642b2d2..3a2a396 100644
--- a/validator_derive/tests/run-pass/custom.rs
+++ b/validator_derive/tests/run-pass/custom.rs
@@ -2,7 +2,7 @@
 
 #[macro_use] extern crate validator_derive;
 extern crate validator;
-use validator::Validate;
+use validator::{Validate, ValidationError};
 
 #[derive(Validate)]
 struct Test {
@@ -10,8 +10,8 @@ struct Test {
     s: String,
 }
 
-fn validate_something(s: &str) -> Option<String> {
-    Some(s.to_string())
+fn validate_something(s: &str) -> Result<(), ValidationError> {
+    Ok(())
 }
 
 fn main() {}
diff --git a/validator_derive/tests/run-pass/schema.rs b/validator_derive/tests/run-pass/schema.rs
index 788d1e2..e219698 100644
--- a/validator_derive/tests/run-pass/schema.rs
+++ b/validator_derive/tests/run-pass/schema.rs
@@ -2,7 +2,7 @@
 
 #[macro_use] extern crate validator_derive;
 extern crate validator;
-use validator::Validate;
+use validator::{Validate, ValidationError};
 
 #[derive(Validate)]
 #[validate(schema(function = "hey"))]
@@ -10,8 +10,8 @@ struct Test {
     s: String,
 }
 
-fn hey(_: &Test) -> Option<(String, String)> {
-    None
+fn hey(_: &Test) -> Result<(), ValidationError> {
+    Ok(())
 }
 
 #[derive(Validate)]
@@ -20,8 +20,9 @@ struct Test2 {
     s: String,
 }
 
-fn hey2(_: &Test2) -> Option<(String, String)> {
-    None
+fn hey2(_: &Test2) -> Result<(), ValidationError> {
+    Ok(())
 }
 
+
 fn main() {}
diff --git a/validator_derive/tests/schema.rs b/validator_derive/tests/schema.rs
new file mode 100644
index 0000000..6b3ae4f
--- /dev/null
+++ b/validator_derive/tests/schema.rs
@@ -0,0 +1,99 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::{Validate, ValidationError};
+
+
+#[test]
+fn can_validate_schema_fn_ok() {
+    fn valid_schema_fn(_: &TestStruct) -> Result<(), ValidationError> {
+    Ok(())
+}
+
+    #[derive(Debug, Validate)]
+    #[validate(schema(function = "valid_schema_fn"))]
+    struct TestStruct {
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "hello".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn can_fail_schema_fn_validation() {
+    fn invalid_schema_fn(_: &TestStruct) -> Result<(), ValidationError> {
+        Err(ValidationError::new("meh"))
+    }
+
+    #[derive(Debug, Validate)]
+    #[validate(schema(function = "invalid_schema_fn"))]
+    struct TestStruct {
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("__all__"));
+    assert_eq!(errs["__all__"].len(), 1);
+    assert_eq!(errs["__all__"][0].code, "meh");
+}
+
+#[test]
+fn can_specify_message_for_schema_fn() {
+    fn invalid_schema_fn(_: &TestStruct) -> Result<(), ValidationError> {
+        Err(ValidationError::new("meh"))
+    }
+
+    #[derive(Debug, Validate)]
+    #[validate(schema(function = "invalid_schema_fn", message = "oops"))]
+    struct TestStruct {
+        val: String,
+    }
+    let s = TestStruct {
+        val: String::new(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("__all__"));
+    assert_eq!(errs["__all__"].len(), 1);
+    assert_eq!(errs["__all__"][0].clone().message.unwrap(), "oops");
+}
+
+#[test]
+fn can_choose_to_run_schema_validation_even_after_field_errors() {
+    fn invalid_schema_fn(_: &TestStruct) -> Result<(), ValidationError> {
+        Err(ValidationError::new("meh"))
+    }
+    #[derive(Debug, Validate)]
+    #[validate(schema(function = "invalid_schema_fn", skip_on_field_errors = "false"))]
+    struct TestStruct {
+        val: String,
+        #[validate(range(min = "1", max = "10"))]
+        num: usize,
+    }
+
+    let s = TestStruct {
+        val: "hello".to_string(),
+        num: 0,
+    };
+
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("__all__"));
+    assert_eq!(errs["__all__"].len(), 1);
+    assert_eq!(errs["__all__"][0].clone().code, "meh");
+    assert!(errs.contains_key("num"));
+    assert_eq!(errs["num"].len(), 1);
+    assert_eq!(errs["num"][0].clone().code, "range");
+}
diff --git a/validator_derive/tests/test_derive.rs b/validator_derive/tests/test_derive.rs
deleted file mode 100644
index 24c408a..0000000
--- a/validator_derive/tests/test_derive.rs
+++ /dev/null
@@ -1,357 +0,0 @@
-#[macro_use] extern crate validator_derive;
-extern crate validator;
-#[macro_use] extern crate serde_derive;
-extern crate serde_json;
-extern crate regex;
-#[macro_use] extern crate lazy_static;
-
-use validator::Validate;
-use regex::Regex;
-
-
-#[derive(Debug, Validate, Deserialize)]
-#[validate(schema(function = "validate_signup", skip_on_field_errors = "false"))]
-struct SignupData {
-    #[validate(email)]
-    mail: String,
-    #[validate(url)]
-    site: String,
-    #[validate(length(min = "1"), custom = "validate_unique_username")]
-    #[serde(rename = "firstName")]
-    first_name: String,
-    #[validate(range(min = "18", max = "20"))]
-    age: u32,
-}
-
-#[derive(Debug, Validate)]
-struct PasswordData {
-    #[validate(must_match = "password2")]
-    password: String,
-    password2: String,
-}
-
-
-fn validate_unique_username(username: &str) -> Option<String> {
-    if username == "xXxShad0wxXx" {
-        return Some("terrible_username".to_string());
-    }
-
-    None
-}
-
-fn validate_signup(data: &SignupData) -> Option<(String, String)> {
-    if data.mail.ends_with("gmail.com") && data.age == 18 {
-        return Some(("all".to_string(), "stupid_rule".to_string()));
-    }
-
-    None
-}
-
-#[derive(Debug, Validate, Deserialize)]
-#[validate(schema(function = "validate_signup2", skip_on_field_errors = "false"))]
-struct SignupData2 {
-    #[validate(email)]
-    mail: String,
-    #[validate(range(min = "18", max = "20"))]
-    age: u32,
-}
-
-#[derive(Debug, Validate, Deserialize)]
-#[validate(schema(function = "validate_signup3"))]
-struct SignupData3 {
-    #[validate(email, contains = "bob")]
-    mail: String,
-    #[validate(range(min = "18", max = "20"))]
-    age: u32,
-}
-
-fn validate_signup2(data: &SignupData2) -> Option<(String, String)> {
-    if data.mail.starts_with("bob") && data.age == 18 {
-        return Some(("mail".to_string(), "stupid_rule".to_string()));
-    }
-
-    None
-}
-
-fn validate_signup3(_: &SignupData3) -> Option<(String, String)> {
-    Some(("mail".to_string(), "stupid_rule".to_string()))
-}
-
-#[test]
-fn test_can_validate_ok() {
-    let signup = SignupData {
-        mail: "bob@bob.com".to_string(),
-        site: "http://hello.com".to_string(),
-        first_name: "Bob".to_string(),
-        age: 18,
-    };
-
-    assert!(signup.validate().is_ok());
-}
-
-#[test]
-fn test_bad_email_fails_validation() {
-    let signup = SignupData {
-        mail: "bob".to_string(),
-        site: "http://hello.com".to_string(),
-        first_name: "Bob".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("mail"));
-    assert_eq!(errs["mail"], vec!["email".to_string()]);
-}
-
-#[test]
-fn test_bad_url_fails_validation() {
-    let signup = SignupData {
-        mail: "bob@bob.com".to_string(),
-        site: "//hello.com".to_string(),
-        first_name: "Bob".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("site"));
-    assert_eq!(errs["site"], vec!["url".to_string()]);
-}
-
-#[test]
-fn test_bad_length_fails_validation_and_points_to_original_name() {
-    let signup = SignupData {
-        mail: "bob@bob.com".to_string(),
-        site: "http://hello.com".to_string(),
-        first_name: "".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("firstName"));
-    assert_eq!(errs["firstName"], vec!["length".to_string()]);
-}
-
-
-#[test]
-fn test_bad_range_fails_validation() {
-    let signup = SignupData {
-        mail: "bob@bob.com".to_string(),
-        site: "https://hello.com".to_string(),
-        first_name: "Bob".to_string(),
-        age: 1,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("age"));
-    assert_eq!(errs["age"], vec!["range".to_string()]);
-}
-
-#[test]
-fn test_can_have_multiple_errors() {
-    let signup = SignupData {
-        mail: "bob@bob.com".to_string(),
-        site: "https://hello.com".to_string(),
-        first_name: "".to_string(),
-        age: 1,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("age"));
-    assert!(errs.contains_key("firstName"));
-    assert_eq!(errs["age"], vec!["range".to_string()]);
-    assert_eq!(errs["firstName"], vec!["length".to_string()]);
-}
-
-#[test]
-fn test_custom_validation_error() {
-    let signup = SignupData {
-        mail: "bob@bob.com".to_string(),
-        site: "https://hello.com".to_string(),
-        first_name: "xXxShad0wxXx".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("firstName"));
-    assert_eq!(errs["firstName"], vec!["terrible_username".to_string()]);
-}
-
-#[test]
-fn test_must_match_can_work() {
-    let data = PasswordData {
-        password: "passw0rd".to_string(),
-        password2: "passw0rd".to_string(),
-    };
-    assert!(data.validate().is_ok())
-}
-
-
-#[test]
-fn test_must_match_can_fail() {
-    let data = PasswordData {
-        password: "passw0rd".to_string(),
-        password2: "password".to_string(),
-    };
-    assert!(data.validate().is_err())
-}
-
-#[test]
-fn test_can_fail_struct_validation_new_key() {
-    let signup = SignupData {
-        mail: "bob@gmail.com".to_string(),
-        site: "https://hello.com".to_string(),
-        first_name: "xXxShad0wxXx".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("all"));
-    assert_eq!(errs["all"], vec!["stupid_rule".to_string()]);
-}
-
-#[test]
-fn test_can_fail_struct_validation_existing_key() {
-    let signup = SignupData2 {
-        mail: "bob".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("mail"));
-    assert_eq!(errs["mail"], vec!["email".to_string(), "stupid_rule".to_string()]);
-}
-
-#[test]
-fn test_skip_struct_validation_by_default_if_errors() {
-    let signup = SignupData3 {
-        mail: "bob".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("mail"));
-    assert_eq!(errs["mail"], vec!["email".to_string()]);
-}
-
-#[test]
-fn test_can_fail_contains_validation() {
-    let signup = SignupData3 {
-        mail: "bo@gmail.com".to_string(),
-        age: 18,
-    };
-    let res = signup.validate();
-    assert!(res.is_err());
-    let errs = res.unwrap_err().inner();
-    assert!(errs.contains_key("mail"));
-    assert_eq!(errs["mail"], vec!["contains".to_string()]);
-}
-
-#[test]
-fn test_can_check_regex_validator() {
-    lazy_static! {
-        static ref RE: Regex = Regex::new(r"[a-z]{2}").unwrap();
-    }
-
-    #[derive(Debug, Validate)]
-    struct RegexStruct {
-        #[validate(regex = "RE")]
-        name: String,
-    }
-    let s = RegexStruct {name: "al".to_string()};
-    assert!(s.validate().is_ok());
-    let s2 = RegexStruct {name: "AL".to_string()};
-    assert!(s2.validate().is_err());
-}
-
-
-#[test]
-fn test_can_validate_option_fields_with_lifetime() {
-    lazy_static! {
-        static ref RE2: Regex = Regex::new(r"[a-z]{2}").unwrap();
-    }
-
-    #[derive(Debug, Validate)]
-    struct PutStruct<'a> {
-        #[validate(length(min = "1", max = "10"))]
-        name: Option<&'a str>,
-        #[validate(range(min = "1", max = "10"))]
-        range: Option<usize>,
-        #[validate(email)]
-        email: Option<&'a str>,
-        #[validate(url)]
-        url: Option<&'a str>,
-        #[validate(contains = "@")]
-        text: Option<&'a str>,
-        #[validate(regex = "RE2")]
-        re: Option<&'a str>,
-        #[validate(custom = "check_str")]
-        custom: Option<&'a str>,
-    }
-
-    fn check_str(_: &str) -> Option<String> {
-        None
-    }
-
-    let s = PutStruct {
-        name: Some("al"),
-        range: Some(2),
-        email: Some("hi@gmail.com"),
-        url: Some("http://google.com"),
-        text: Some("@someone"),
-        re: Some("hi"),
-        custom: Some("hey"),
-    };
-    assert!(s.validate().is_ok());
-}
-
-#[test]
-fn test_can_validate_option_fields_without_lifetime() {
-    lazy_static! {
-        static ref RE2: Regex = Regex::new(r"[a-z]{2}").unwrap();
-    }
-
-    #[derive(Debug, Validate)]
-    struct PutStruct {
-        #[validate(length(min = "1", max = "10"))]
-        name: Option<String>,
-        #[validate(length(min = "1", max = "10"))]
-        ids: Option<Vec<usize>>,
-        #[validate(range(min = "1", max = "10"))]
-        range: Option<usize>,
-        #[validate(email)]
-        email: Option<String>,
-        #[validate(url)]
-        url: Option<String>,
-        #[validate(contains = "@")]
-        text: Option<String>,
-        #[validate(regex = "RE2")]
-        re: Option<String>,
-        #[validate(custom = "check_str")]
-        custom: Option<String>,
-    }
-
-    fn check_str(_: &str) -> Option<String> {
-        None
-    }
-
-    let s = PutStruct {
-        name: Some("al".to_string()),
-        ids: Some(vec![1, 2, 3]),
-        range: Some(2),
-        email: Some("hi@gmail.com".to_string()),
-        url: Some("http://google.com".to_string()),
-        text: Some("@someone".to_string()),
-        re: Some("hi".to_string()),
-        custom: Some("hey".to_string()),
-    };
-    assert!(s.validate().is_ok());
-}
diff --git a/validator_derive/tests/url.rs b/validator_derive/tests/url.rs
new file mode 100644
index 0000000..1182086
--- /dev/null
+++ b/validator_derive/tests/url.rs
@@ -0,0 +1,77 @@
+#[macro_use]
+extern crate validator_derive;
+extern crate validator;
+
+use validator::Validate;
+
+
+#[test]
+fn can_validate_url_ok() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(url)]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "https://google.com".to_string(),
+    };
+
+    assert!(s.validate().is_ok());
+}
+
+#[test]
+fn bad_url_fails_validation() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(url)]
+        val: String,
+    }
+
+    let s = TestStruct {
+        val: "bob".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "url");
+}
+
+#[test]
+fn can_specify_code_for_url() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(url(code = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: "bob".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].code, "oops");
+    assert_eq!(errs["val"][0].params["value"], "bob");
+}
+
+#[test]
+fn can_specify_message_for_url() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(url(message = "oops"))]
+        val: String,
+    }
+    let s = TestStruct {
+        val: "bob".to_string(),
+    };
+    let res = s.validate();
+    assert!(res.is_err());
+    let errs = res.unwrap_err().inner();
+    assert!(errs.contains_key("val"));
+    assert_eq!(errs["val"].len(), 1);
+    assert_eq!(errs["val"][0].clone().message.unwrap(), "oops");
+}
-- 
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