From 3a0a4c89532c0b425688aa5b090022cb9ef3fc66 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 25 Mar 2023 11:59:19 -0400
Subject: [PATCH] Consume the trailing whitespace after a headline.

---
 src/parser/document.rs |  3 ++-
 src/parser/element.rs  | 13 +++----------
 src/parser/util.rs     | 22 ++++++++++++++++++++++
 toy_language.txt       |  4 ++++
 4 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/src/parser/document.rs b/src/parser/document.rs
index 352ddc81..81f1a68c 100644
--- a/src/parser/document.rs
+++ b/src/parser/document.rs
@@ -29,6 +29,7 @@ use super::parser_with_context::parser_with_context;
 use super::source::Source;
 use super::util::get_consumed;
 use super::util::get_one_before;
+use super::util::trailing_whitespace;
 use super::Context;
 
 #[derive(Debug)]
@@ -151,7 +152,7 @@ fn headline<'r, 's>(
         many1_count(tag("*")),
         space1,
         many1(standard_set_object_matcher),
-        alt((line_ending, eof)),
+        trailing_whitespace,
     ))(input)?;
     Ok((remaining, (star_count, ws, title, ws2)))
 }
diff --git a/src/parser/element.rs b/src/parser/element.rs
index 88d44cc5..3ae3d1a3 100644
--- a/src/parser/element.rs
+++ b/src/parser/element.rs
@@ -19,7 +19,9 @@ use super::error::Res;
 use super::greater_element::PlainList;
 use super::lesser_element::Paragraph;
 use super::source::Source;
+use super::util::blank_line;
 use super::util::get_consumed;
+use super::util::trailing_whitespace;
 use super::Context;
 
 #[derive(Debug)]
@@ -54,8 +56,7 @@ fn paragraph<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, P
 
     let (remaining, children) = many1(standard_set_object_matcher)(input)?;
 
-    let (remaining, _trailing_whitespace) =
-        alt((eof, recognize(tuple((line_ending, many0(blank_line))))))(remaining)?;
+    let (remaining, _trailing_whitespace) = trailing_whitespace(remaining)?;
 
     let source = get_consumed(input, remaining);
 
@@ -66,11 +67,3 @@ fn paragraph_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s st
     // TODO: Other elements should also end paragraphs
     alt((recognize(tuple((line_ending, many1(blank_line)))), eof))(input)
 }
-
-/// 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.
-fn blank_line(input: &str) -> Res<&str, &str> {
-    not(eof)(input)?;
-    recognize(tuple((space0, alt((line_ending, eof)))))(input)
-}
diff --git a/src/parser/util.rs b/src/parser/util.rs
index cf4b3f79..9962dc78 100644
--- a/src/parser/util.rs
+++ b/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::*;
diff --git a/toy_language.txt b/toy_language.txt
index 2f8aa337..614291fd 100644
--- a/toy_language.txt
+++ b/toy_language.txt
@@ -11,3 +11,7 @@ text*
 
 
 *nesting *bold entrances* and* exits
+
+* Heading
+
+body of heading