Allow emphasized phrases to include underscores. [#110 state:resolved]

CHANGELOG

@@ -1,5 +1,7 @@
 === Edge
 
+* Allow emphasized phrases to include underscores. [Jason Garber]
+
 * Include an ending question mark in a citation. [Jason Garber]
 
 * Preserve leading whitespace in pre and bc blocks. [Jason Garber]

ext/redcloth_scan/redcloth_inline.rl

@@ -48,8 +48,10 @@
   script_tag = ( "<script" [^>]* ">" (default+ -- "</script>") "</script>" LF? ) >X >A %T ;
   strong = "["? "*" >X mtext >A %T :> "*" "]"? ;
   b = "["? "**" >X mtext >A %T :> "**" "]"? ;
-  em = "["? "_" >X mtext >A %T :> "_" "]"? ;
-  i = "["? "__" >X mtext >A %T :> "__" "]"? ;
+  mtext_excluding_underscore = mtext -- "_" ;
+  emtext = mtext_excluding_underscore ("_" mtext_excluding_underscore)*;
+  em = "["? "_" >X emtext >A %T "_" "]"? ;
+  i = "["? "__" >X emtext >A %T :>> ("__" "]"?) ;
   del = "[-" >X C ( mtext ) >A %T :>> "-]" ;
   emdash_parenthetical_phrase_with_spaces = " -- " mtext " -- " ;
   del_phrase = (( " " >A %{ STORE("beginning_space"); } "-" | "-" when starts_line) >X C ( mtext ) >A %T :>> ( "-" end_markup_phrase )) - emdash_parenthetical_phrase_with_spaces ;

spec/fixtures/basic.yml

@@ -949,7 +949,7 @@ in: |-
 
   Some more text.
 html: |-
-  <p>Just some <em>_</em> text</p>
+  <p>Just some ___ text</p>
   <hr />
   <p>Some more text.</p>
 ---
@@ -988,3 +988,11 @@ name: citation including question mark
 in: "??What's the Matter with Kansas? How Conservatives Won the Heart of America?? is a great book!"
 html: |-
   <p><cite>What&#8217;s the Matter with Kansas? How Conservatives Won the Heart of America</cite> is a great book!</p>
+---
+name: emphasized word including underscore
+in: |-
+  _trythis_ it will keep the empahsis.
+  _and_this_too_ it should keep the emphasis but does not with redcloth.
+html: |-
+  <p><em>trythis</em> it will keep the empahsis.<br />
+  <em>and_this_too</em> it should keep the emphasis but does not with redcloth.</p>