Implement the horizontal rule parser.

src/parser/element.rs

@@ -11,6 +11,7 @@ use super::lesser_element::DiarySexp;
 use super::lesser_element::ExampleBlock;
 use super::lesser_element::ExportBlock;
 use super::lesser_element::FixedWidthArea;
+use super::lesser_element::HorizontalRule;
 use super::lesser_element::Paragraph;
 use super::lesser_element::Planning;
 use super::lesser_element::SrcBlock;
@@ -38,6 +39,7 @@ pub enum Element<'s> {
     DiarySexp(DiarySexp<'s>),
     Planning(Planning<'s>),
     FixedWidthArea(FixedWidthArea<'s>),
+    HorizontalRule(HorizontalRule<'s>),
 }
 
 impl<'s> Source<'s> for Element<'s> {
@@ -61,6 +63,7 @@ impl<'s> Source<'s> for Element<'s> {
             Element::DiarySexp(obj) => obj.source,
             Element::Planning(obj) => obj.source,
             Element::FixedWidthArea(obj) => obj.source,
+            Element::HorizontalRule(obj) => obj.source,
         }
     }
 }

src/parser/element_parser.rs

@@ -7,6 +7,7 @@ use super::element::Element;
 use super::fixed_width_area::fixed_width_area;
 use super::footnote_definition::footnote_definition;
 use super::greater_block::greater_block;
+use super::horizontal_rule::horizontal_rule;
 use super::lesser_block::comment_block;
 use super::lesser_block::example_block;
 use super::lesser_block::export_block;
@@ -51,6 +52,7 @@ pub fn non_paragraph_element<'r, 's>(
     let clock_matcher = parser_with_context!(clock)(context);
     let diary_sexp_matcher = parser_with_context!(diary_sexp)(context);
     let fixed_width_area_matcher = parser_with_context!(fixed_width_area)(context);
+    let horizontal_rule_matcher = parser_with_context!(horizontal_rule)(context);
     alt((
         map(plain_list_matcher, Element::PlainList),
         map(greater_block_matcher, Element::GreaterBlock),
@@ -67,5 +69,6 @@ pub fn non_paragraph_element<'r, 's>(
         map(clock_matcher, Element::Clock),
         map(diary_sexp_matcher, Element::DiarySexp),
         map(fixed_width_area_matcher, Element::FixedWidthArea),
+        map(horizontal_rule_matcher, Element::HorizontalRule),
     ))(input)
 }

src/parser/horizontal_rule.rs

@@ -0,0 +1,29 @@
+use nom::branch::alt;
+use nom::bytes::complete::tag;
+use nom::character::complete::line_ending;
+use nom::character::complete::space0;
+use nom::combinator::eof;
+use nom::combinator::recognize;
+use nom::combinator::verify;
+use nom::multi::many1_count;
+use nom::sequence::tuple;
+
+use super::Context;
+use crate::error::Res;
+use crate::parser::util::start_of_line;
+use crate::parser::HorizontalRule;
+
+#[tracing::instrument(ret, level = "debug")]
+pub fn horizontal_rule<'r, 's>(
+    context: Context<'r, 's>,
+    input: &'s str,
+) -> Res<&'s str, HorizontalRule<'s>> {
+    start_of_line(context, input)?;
+    let (remaining, rule) = recognize(tuple((
+        space0,
+        verify(many1_count(tag("-")), |dashes| *dashes >= 5),
+        space0,
+        alt((line_ending, eof)),
+    )))(input)?;
+    Ok((remaining, HorizontalRule { source: rule }))
+}

src/parser/lesser_element.rs

@@ -79,6 +79,11 @@ pub struct FixedWidthArea<'s> {
     pub source: &'s str,
 }
 
+#[derive(Debug)]
+pub struct HorizontalRule<'s> {
+    pub source: &'s str,
+}
+
 impl<'s> Paragraph<'s> {
     pub fn of_text(input: &'s str) -> Self {
         let mut objects = Vec::with_capacity(1);
@@ -157,3 +162,9 @@ impl<'s> Source<'s> for FixedWidthArea<'s> {
         self.source
     }
 }
+
+impl<'s> Source<'s> for HorizontalRule<'s> {
+    fn get_source(&'s self) -> &'s str {
+        self.source
+    }
+}

src/parser/mod.rs

@@ -11,6 +11,7 @@ mod fixed_width_area;
 mod footnote_definition;
 mod greater_block;
 mod greater_element;
+mod horizontal_rule;
 mod lesser_block;
 mod lesser_element;
 mod list;
@@ -49,6 +50,7 @@ pub use lesser_element::DiarySexp;
 pub use lesser_element::ExampleBlock;
 pub use lesser_element::ExportBlock;
 pub use lesser_element::FixedWidthArea;
+pub use lesser_element::HorizontalRule;
 pub use lesser_element::Paragraph;
 pub use lesser_element::Planning;
 pub use lesser_element::SrcBlock;