From dc9f3eb2e6c6fb289e08dcbe9c980e4eb7d9e267 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Fri, 24 Mar 2023 17:00:27 -0400
Subject: [PATCH] Implement the section parser.

---
 src/parser/document.rs | 16 +++++++++++++++-
 src/parser/element.rs  |  9 +++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/parser/document.rs b/src/parser/document.rs
index bec0cab0..32c408ff 100644
--- a/src/parser/document.rs
+++ b/src/parser/document.rs
@@ -9,6 +9,7 @@ use nom::multi::many1;
 use nom::multi::many1_count;
 use nom::sequence::tuple;
 
+use crate::parser::element::element;
 use crate::parser::error::CustomError;
 use crate::parser::error::MyError;
 use crate::parser::object::standard_set_object;
@@ -81,7 +82,10 @@ fn section<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, Sec
         }))
         .with_additional_node(ContextElement::Context("section"));
     not(|i| parser_context.check_exit_matcher(i))(input)?;
-    todo!()
+    let element_matcher = parser_with_context!(element)(&parser_context);
+    let (remaining, children) = many1(element_matcher)(input)?;
+    let source = get_consumed(input, remaining);
+    Ok((remaining, Section { source, children }))
 }
 
 fn section_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
@@ -160,6 +164,16 @@ fn is_slice_of(parent: &str, child: &str) -> bool {
     child_start >= parent_start && child_end <= parent_end
 }
 
+/// Get a slice of the string that was consumed in a parser using the original input to the parser and the remaining input after the parser.
+fn get_consumed<'s>(input: &'s str, remaining: &'s str) -> &'s str {
+    assert!(is_slice_of(input, remaining));
+    let source = {
+        let offset = remaining.as_ptr() as usize - input.as_ptr() as usize;
+        &input[..offset]
+    };
+    source
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/src/parser/element.rs b/src/parser/element.rs
index eb7ed8c5..ecfa993e 100644
--- a/src/parser/element.rs
+++ b/src/parser/element.rs
@@ -1,6 +1,10 @@
+use nom::combinator::not;
+
+use super::error::Res;
 use super::greater_element::PlainList;
 use super::lesser_element::Paragraph;
 use super::source::Source;
+use super::Context;
 
 #[derive(Debug)]
 pub enum Element<'s> {
@@ -16,3 +20,8 @@ impl<'s> Source<'s> for Element<'s> {
         }
     }
 }
+
+pub fn element<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, Element<'s>> {
+    not(|i| context.check_exit_matcher(i))(input)?;
+    todo!()
+}