First doctree conversion code

1 files changed, 78 insertions, 4 deletions

diff --git a/src/parser.rs b/src/parser.rs
index 026024a..fa12b3e 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -3,8 +3,82 @@ pub mod serialize;
 #[cfg(test)]
 pub mod tests;
 
-use pest_derive::Parser;
+mod pest_rst {
+    use pest_derive::Parser;
+    
+    #[derive(Parser)]
+    #[grammar = "rst.pest"]
+    pub struct RstParser;
+}
+use self::pest_rst::Rule;
 
-#[derive(Parser)]
-#[grammar = "rst.pest"]
-pub struct RstParser;
+use std::io::Write;
+
+use failure::Error;
+use failure_derive::Fail;
+
+use pest::Parser;
+
+use crate::document_tree::{
+    HasChildren,
+    elements::{
+        Document,
+        Title,
+    },
+    element_categories::{
+        StructuralSubElement
+    },
+};
+
+
+#[derive(Debug, Fail)]
+enum ConversionError {
+    #[fail(display = "unknown rule: {:?}", rule)]
+    UnknownRuleError {
+        rule: Rule,
+    },
+}
+
+
+fn convert_ssubel(pair: pest::iterators::Pair<Rule>) -> Result<StructuralSubElement, Error> {
+    match pair.as_rule() {
+        Rule::title => Ok(convert_title(pair).into()),
+        rule => Err(ConversionError::UnknownRuleError { rule }.into()),
+    }
+}
+
+
+fn convert_title(pair: pest::iterators::Pair<pest_rst::Rule>) -> 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
+    Title::with_children(vec![
+        title.expect("No text in title").into()
+    ])
+}
+
+
+/// tokens to Document tree. resolves sections, but not references
+pub fn parse(source: &str) -> Result<Document, Error> {
+    let pairs = pest_rst::RstParser::parse(pest_rst::Rule::document, source)?;
+    let structural_elems = pairs.map(convert_ssubel).collect::<Result<_, _>>()?;
+    Ok(Document::with_children(structural_elems))
+}
+
+
+/// only until we can serialize DocumentTrees
+pub fn serialize_json<W>(source: &str, stream: W) -> Result<(), Error> where W: Write {
+    use self::pest_rst::{RstParser, Rule};
+    use self::serialize::PairsWrap;
+    
+    let parsed = RstParser::parse(Rule::document, source)?;
+    serde_json::to_writer(stream, &PairsWrap(parsed))?;
+    Ok(())
+}