Syntax changed to !merge(space | comma)

* Syntax changed to !merge(space | comma)
* !merge(space) implemented by Expression instead of Value.
* Added test for lonely property with !merge directive

lib/less/parser.js

@@ -1501,12 +1501,13 @@ less.Parser = function Parser(env) {
                 var separator;
                 if (input.charAt(i) === '!') {
                     if ($(/^! *merge\(/)) {
-                        if (input.charAt(i) === ")") {
-                            separator = " ";
-                        } else {
-                            separator = $(/[^)]/);
-                        }
-                        expect(")");
+                        separator = expect(/^ *space|comma */);
+						if (separator) {
+						    separator = (separator.trim() === 'space')
+						        ? ' ' 
+							    : ',';
+						}
+                        expect(')');
                     }
                 }
                 return separator;

lib/less/tree/ruleset.js

@@ -485,9 +485,11 @@ tree.Ruleset.prototype = {
             parts = groups[k];
 
             if (parts.length > 1) {
-                parts[0].value = new (tree.Value)(parts.map(function (p) {
-                    return p.value;
-                }), rule.merge);
+				rule = parts[0];
+				
+				rule.value = new ((rule.merge === ' ') ? tree.Expression : tree.Value)(parts.map(function (p) {
+					return p.value;
+				}));
             }
         });
     }

lib/less/tree/value.js

@@ -1,8 +1,7 @@
 (function (tree) {
 
-tree.Value = function (value, separator) {
+tree.Value = function (value) {
     this.value = value;
-    this.separator = separator ? separator : ",";
 };
 tree.Value.prototype = {
     type: "Value",
@@ -21,7 +20,7 @@ tree.Value.prototype = {
     toCSS: function (env) {
         return this.value.map(function (e) {
             return e.toCSS(env);
-        }).join(this.separator + ((env.compress || this.separator === " ") ? "" : " "));
+        }).join(env.compress ? ',' : ', ');
     }
 };