added $propdoc to AST nodes and some cleanups

hopefully we can make the AST documentation self-generating

lib/parse.js

@@ -528,7 +528,7 @@ function tokenizer($TEXT, filename) {
                 regexp += ch;
             }
             var mods = read_name();
-            return token("regexp", [ regexp, mods ]);
+            return token("regexp", new RegExp(regexp, mods));
         });
     };
 
@@ -1160,7 +1160,7 @@ function parse($TEXT, options) {
             ret = new AST_String({ start: tok, end: tok, value: tok.value });
             break;
           case "regexp":
-            ret = new AST_RegExp({ start: tok, end: tok, pattern: tok.value[0], mods: tok.value[1] });
+            ret = new AST_RegExp({ start: tok, end: tok, value: tok.value });
             break;
           case "atom":
             switch (tok.value) {