Code structure for keyword.

src/parser/keyword.rs

@@ -0,0 +1,26 @@
+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::Keyword;
+
+#[tracing::instrument(ret, level = "debug")]
+pub fn keyword<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, Keyword<'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, Keyword { source: rule }))
+}