Consume the trailing whitespace after a headline.

src/parser/util.rs

@@ -1,3 +1,13 @@
+use nom::branch::alt;
+use nom::character::complete::line_ending;
+use nom::character::complete::space0;
+use nom::combinator::eof;
+use nom::combinator::not;
+use nom::combinator::recognize;
+use nom::multi::many0;
+use nom::sequence::tuple;
+
+use super::error::Res;
 use super::parser_context::ContextElement;
 use super::Context;
 
@@ -54,6 +64,18 @@ pub fn get_consumed<'s>(input: &'s str, remaining: &'s str) -> &'s str {
     source
 }
 
+/// A line containing only whitespace and then a line break
+///
+/// It is up to the caller to ensure this is called at the start of a line.
+pub fn blank_line(input: &str) -> Res<&str, &str> {
+    not(eof)(input)?;
+    recognize(tuple((space0, alt((line_ending, eof)))))(input)
+}
+
+pub fn trailing_whitespace(input: &str) -> Res<&str, &str> {
+    alt((eof, recognize(tuple((line_ending, many0(blank_line))))))(input)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;