parser: allow totally empty comments

This is important for txn body comments
as some editors removes spaces at the end of line

Signed-off-by: 35V LG84 <[email protected]>

tackler-core/src/parser/parts/comment.rs

@@ -5,18 +5,30 @@
  */
 
 use crate::parser::Stream;
-use winnow::ascii::till_line_ending;
+use winnow::ascii::{line_ending, till_line_ending};
+use winnow::combinator::{alt, peek};
 use winnow::stream::AsChar;
 use winnow::token::one_of;
 use winnow::{seq, PResult, Parser};
 
 pub(crate) fn p_comment<'s>(is: &mut Stream<'s>) -> PResult<&'s str> {
     let m = seq!(
         _: ';',
-        // this can not be space1 as we must preserve space for equity and identity reports
-        _: one_of(AsChar::is_space),
-        till_line_ending,
+        alt((
+            seq!(
+                // this can not be space1 as we must preserve space for equity and identity reports
+                _: one_of(AsChar::is_space),
+                till_line_ending
+            ),
+            // allow totally empty comment ";\n" - this is important for
+            // txn body comments as some editors removes spaces at the end of line
+            peek(line_ending).map(|_| {("",)})
+        )).map(|x| x.0),
     )
+    .map(|x| x.0)
     .parse_next(is)?;
-    Ok(m.0)
+    Ok(m)
 }
+
+// The line_end handling must work with outer contex,
+// so for testing, see txn_comment.rs

tackler-core/src/parser/parts/txn_comment.rs

@@ -18,3 +18,37 @@ pub(crate) fn parse_txn_comment<'s>(is: &mut Stream<'s>) -> PResult<&'s str> {
     .parse_next(is)?;
     Ok(m.0)
 }
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::kernel::Settings;
+
+    #[test]
+    fn test_txn_comment() {
+        let comments = vec![
+            (" ; comment\n", "comment"),
+            ("\t;\tcomment\n", "comment"),
+            (" \t; \tcomment\n", "\tcomment"),
+            ("\t ;\t comment\n", " comment"),
+            (" ; comment \n", "comment "),
+            ("\t;\tcomment\t\n", "comment\t"),
+            ("\t ;\n", ""),
+            (" ;    \n", "   "),
+            (" ;\t\t\n", "\t"),
+            (" ; \t \n", "\t "),
+        ];
+        let mut settings = Settings::default();
+
+        for c in comments {
+            let mut is = Stream {
+                input: c.0,
+                state: &mut settings,
+            };
+
+            let res = parse_txn_comment(&mut is);
+
+            assert!(res.is_ok());
+            assert_eq!(c.1, res.unwrap(/*:test:*/));
+        }
+    }
+}