parser.leg: scan for setext pattern before parsing Inlines (from jgm/peg-markdown)

README.markdown

@@ -67,23 +67,6 @@ See the [original README][] for details.
 [original README]: https://github.com/jgm/peg-markdown/blob/master/README.markdown
 [knieriem/peg]: https://github.com/knieriem/peg
 
-## Known issues
-
-Emphasis and strong markup within items of lists, as in input
-like ./PHP Markdown Extra.mdtest/Emphasis.text from Michel
-Fortin's [MDTest][] package,
-
-	1.  ***test test***
-	2.  ___test test___
-	3.  *test **test***
-	4.  **test *test***
-	...
-
-seem to present a problem for the LEG parser, which needs
-(on my system) around four minutes to process that file.
-
-[MDTest]: http://git.michelf.com/mdtest/
-
 ## Todo
 
 *	Implement definition lists (work in progress), and perhaps tables

parser.leg

@@ -137,11 +137,17 @@ AtxHeading = s:AtxStart Sp a:StartList ( AtxInline { a = cons($$, a) } )+ (Sp '#
 
 SetextHeading = SetextHeading1 | SetextHeading2
 
-SetextHeading1 =  a:StartList ( !Endline Inline { a = cons($$, a) } )+ Newline "===" '='* Newline
-                  { $$ = mk_list(H1, a) }
+SetextBottom1 = "===" '='* Newline
 
-SetextHeading2 =  a:StartList ( !Endline Inline { a = cons($$, a) } )+ Newline "---" '-'* Newline
-                  { $$ = mk_list(H2, a) }
+SetextBottom2 = "---" '-'* Newline
+
+SetextHeading1 =  &(RawLine SetextBottom1)
+                  a:StartList ( !Endline Inline { a = cons($$, a) } )+ Newline
+                  SetextBottom1 { $$ = mk_list(H1, a) }
+
+SetextHeading2 =  &(RawLine SetextBottom2)
+                  a:StartList ( !Endline Inline { a = cons($$, a) } )+ Newline
+                  SetextBottom2 { $$ = mk_list(H2, a) }
 
 Heading = AtxHeading | SetextHeading