allowing more flexible whitespace-started regexes. You have to wrap 'em in parens or assign to 'em, but it's better than nothing.

lib/lexer.js

@@ -191,8 +191,11 @@
       return true;
     };
     Lexer.prototype.regexToken = function() {
-      var end, flags, regex, str;
-      if (!(this.chunk.match(REGEX_START))) {
+      var _d, end, first, flags, regex, str;
+      if (!(first = this.chunk.match(REGEX_START))) {
+        return false;
+      }
+      if (first[1] === ' ' && !('CALL_START' === (_d = this.tag()) || '=' === _d)) {
         return false;
       }
       if (include(NOT_REGEX, this.tag())) {
@@ -606,7 +609,7 @@
   MULTI_DENT = /^((\n([ \t]*))+)(\.)?/;
   LAST_DENTS = /\n([ \t]*)/g;
   LAST_DENT = /\n([ \t]*)/;
-  REGEX_START = /^\/[^\/ ]/;
+  REGEX_START = /^\/([^\/])/;
   REGEX_INTERPOLATION = /([^\\]#\{.*[^\\]\})/;
   REGEX_END = /^(([imgy]{1,4})\b|\W|$)/;
   REGEX_ESCAPE = /\\[^\$]/g;

src/lexer.coffee

@@ -163,7 +163,8 @@ exports.Lexer = class Lexer
   # JavaScript and Ruby, borrow slash balancing from `@balancedToken`, and
   # borrow interpolation from `@interpolateString`.
   regexToken: ->
-    return false unless @chunk.match REGEX_START
+    return false unless first = @chunk.match REGEX_START
+    return false if first[1] is ' ' and @tag() not in ['CALL_START', '=']
     return false if     include NOT_REGEX, @tag()
     return false unless regex = @balancedToken ['/', '/']
     return false unless end = @chunk.substr(regex.length).match REGEX_END
@@ -527,7 +528,7 @@ LAST_DENTS    = /\n([ \t]*)/g
 LAST_DENT     = /\n([ \t]*)/
 
 # Regex-matching-regexes.
-REGEX_START         = /^\/[^\/ ]/
+REGEX_START         = /^\/([^\/])/
 REGEX_INTERPOLATION = /([^\\]#\{.*[^\\]\})/
 REGEX_END           = /^(([imgy]{1,4})\b|\W|$)/
 REGEX_ESCAPE        = /\\[^\$]/g

test/test_regexps.coffee

@@ -20,4 +20,9 @@ obj = {
 }
 id = 2
 
+ok ' '.match(/ /)[0] is ' '
+
+regexp = / /
+ok ' '.match regexp
+
 ok (obj.width()/id - obj.height()/id) is -5