1 files changed, 99 insertions, 0 deletions
diff --git a/src/parser/conversion.rs b/src/parser/conversion.rs
new file mode 100644
index 0000000..5fc9605
--- /dev/null
+++ b/src/parser/conversion.rs
@@ -0,0 +1,99 @@
+use url::Url;
+use failure::Error;
+use failure_derive::Fail;
+use pest::iterators::{Pairs,Pair};
+
+use crate::document_tree::{
+    HasChildren,
+    elements as e,
+    element_categories as c,
+    attribute_types::ID,
+    extra_attributes,
+};
+
+use super::pest_rst::Rule;
+
+#[derive(Debug, Fail)]
+enum ConversionError {
+    #[fail(display = "unknown rule: {:?}", rule)]
+    UnknownRuleError {
+        rule: Rule,
+    },
+}
+
+
+pub fn convert_document(pairs: Pairs<Rule>) -> Result<e::Document, Error> {
+    let structural_elems = pairs.map(convert_ssubel).collect::<Result<_,_>>()?;
+    Ok(e::Document::with_children(structural_elems))
+}
+
+
+fn convert_ssubel(pair: Pair<Rule>) -> Result<c::StructuralSubElement, Error> {
+    // TODO: This is just a proof of concep. Keep closely to DTD in final version!
+    match pair.as_rule() {
+        Rule::title => Ok(convert_title(pair).into()),
+        Rule::paragraph => Ok(to_ssub(e::Paragraph::with_children(vec![pair.as_str().into()]))),
+        Rule::target => Ok(to_ssub(convert_target(pair)?)),
+        Rule::admonition_gen => Ok(to_ssub(convert_admonition_gen(pair)?)),
+        rule => Err(ConversionError::UnknownRuleError { rule }.into()),
+    }
+}
+
+
+fn to_ssub<E>(elem: E) -> c::StructuralSubElement where E: Into<c::BodyElement> {
+    let belm: c::BodyElement = elem.into();
+    let sstruc: c::SubStructure = belm.into();
+    sstruc.into()
+}
+
+
+fn convert_title(pair: Pair<Rule>) -> e::Title {
+    let mut title: Option<&str> = None;
+    let mut _adornment_char: Option<char> = None;
+    for p in pair.into_inner() {
+        match p.as_rule() {
+            Rule::line => title = Some(p.as_str()),
+            Rule::adornments => _adornment_char = Some(p.as_str().chars().next().expect("Empty adornment?")),
+            rule => panic!("Unexpected rule in title: {:?}", rule),
+        };
+    }
+    // TODO adornment char
+    e::Title::with_children(vec![
+        title.expect("No text in title").into()
+    ])
+}
+
+fn convert_target(pair: Pair<Rule>) -> Result<e::Target, Error> {
+    let mut attrs = extra_attributes::Target {
+        anonymous: false,
+        ..Default::default()
+    };
+    for p in pair.into_inner() {
+        match p.as_rule() {
+            // TODO: or is it refnames?
+            Rule::target_name_uq | Rule::target_name_qu => attrs.refid = Some(ID(p.as_str().to_owned())),
+            Rule::link_target => attrs.refuri = Some(Url::parse(p.as_str())?),
+            rule => panic!("Unexpected rule in target: {:?}", rule),
+        }
+    }
+    Ok(e::Target::new(Default::default(), attrs))
+}
+
+fn convert_admonition_gen(pair: Pair<Rule>) -> Result<c::BodyElement, Error> {
+    let mut iter = pair.into_inner();
+    let typ = iter.next().unwrap().as_str();
+    // TODO: in reality it contains body elements.
+    let children: Vec<c::BodyElement> = iter.map(|p| e::Paragraph::with_children(vec![p.as_str().into()]).into()).collect();
+    Ok(match typ {
+        "attention" => e::Attention::with_children(children).into(),
+        "hint"      =>      e::Hint::with_children(children).into(),
+        "note"      =>      e::Note::with_children(children).into(),
+        "caution"   =>   e::Caution::with_children(children).into(),
+        "danger"    =>    e::Danger::with_children(children).into(),
+        "error"     =>     e::Error::with_children(children).into(),
+        "important" => e::Important::with_children(children).into(),
+        "tip"       =>       e::Tip::with_children(children).into(),
+        "warning"   =>   e::Warning::with_children(children).into(),
+        typ         => panic!("Unknown admontion type {}!", typ),
+    })
+}