Building the plain list item context.

src/parser/plain_list.rs

@@ -1,5 +1,22 @@
+use nom::branch::alt;
+use nom::character::complete::space0;
+use nom::combinator::eof;
+use nom::combinator::not;
+use nom::combinator::recognize;
+use nom::combinator::verify;
+use nom::sequence::tuple;
+
+use crate::parser::parser_context::ChainBehavior;
+use crate::parser::parser_context::ContextElement;
+use crate::parser::parser_context::ExitMatcherNode;
+use crate::parser::util::start_of_line;
+
+use super::error::CustomError;
+use super::error::MyError;
 use super::error::Res;
 use super::lesser_element::Paragraph;
+use super::parser_with_context::parser_with_context;
+use super::util::non_whitespace_character;
 use super::Context;
 
 #[allow(dead_code)]
@@ -7,5 +24,52 @@ pub fn plain_list_item<'r, 's>(
     context: Context<'r, 's>,
     input: &'s str,
 ) -> Res<&'s str, Paragraph<'s>> {
+    not(|i| context.check_exit_matcher(i))(input)?;
+    start_of_line(context, input)?;
+    let (remaining, leading_whitespace) = space0(input)?;
+    // It is fine that we get the indent level using the number of bytes rather than the number of characters because nom's space0 only matches space and tab (0x20 and 0x09)
+    let indent_level = leading_whitespace.len();
+    let list_item_context = context
+        .with_additional_node(ContextElement::ExitMatcherNode(ExitMatcherNode {
+            exit_matcher: ChainBehavior::AndParent(Some(&plain_list_item_end)),
+        }))
+        .with_additional_node(ContextElement::ListItem(indent_level));
     todo!()
 }
+
+fn plain_list_item_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
+    let plain_list_item_matcher = parser_with_context!(plain_list_item)(context);
+    let line_indented_lte_matcher = parser_with_context!(line_indented_lte)(context);
+    alt((
+        recognize(plain_list_item_matcher),
+        line_indented_lte_matcher,
+        eof,
+    ))(input)
+}
+
+fn line_indented_lte<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
+    let current_item_indent_level: &usize =
+        get_context_item_indent(context).ok_or(nom::Err::Error(CustomError::MyError(MyError(
+            "Not inside a plain list item",
+        ))))?;
+
+    start_of_line(context, input)?;
+
+    let matched = recognize(verify(
+        tuple((space0::<&str, _>, non_whitespace_character)),
+        // It is fine that we get the indent level using the number of bytes rather than the number of characters because nom's space0 only matches space and tab (0x20 and 0x09)
+        |(_space0, _anychar)| _space0.len() <= *current_item_indent_level,
+    ))(input)?;
+
+    Ok(matched)
+}
+
+fn get_context_item_indent<'r, 's>(context: Context<'r, 's>) -> Option<&'r usize> {
+    for thing in context.iter() {
+        match thing.get_data() {
+            ContextElement::ListItem(depth) => return Some(depth),
+            _ => {}
+        };
+    }
+    None
+}