support strings as properties

Example:

  @Property: "border-radius";
  ~"-webkit-@{property}": 5px;

lib/less/parser.js

@@ -1034,6 +1034,18 @@ less.Parser = function Parser(env) {
                         furthest = i;
                         restore();
                     }
+                } else if (name = $(this.entities.quoted)) {
+                  if ($(/\s*:/)) {
+                    value = $(this.value);
+                    important = $(this.important);
+
+                    if (value && $(this.end)) {
+                      return new(tree.Rule)(name, value, important, memo);
+                    } else {
+                      furthest = i;
+                      restore();
+                    }
+                  }
                 }
             },
 

lib/less/tree/rule.js

@@ -6,22 +6,26 @@ tree.Rule = function (name, value, important, index, inline) {
     this.important = important ? ' ' + important.trim() : '';
     this.index = index;
     this.inline = inline || false;
+    this.quotedName = false;
 
-    if (name.charAt(0) === '@') {
+    if (!name.charAt) {
+      this.quotedName = true;
+    } else if (name.charAt(0) === '@') {
         this.variable = true;
     } else { this.variable = false }
 };
 tree.Rule.prototype.toCSS = function (env) {
     if (this.variable) { return "" }
     else {
-        return this.name + (env.compress ? ':' : ': ') +
+        return (this.quotedName ? this.name.toCSS(env) : this.name) +
+               (env.compress ? ':' : ': ') +
                this.value.toCSS(env) +
                this.important + (this.inline ? "" : ";");
     }
 };
 
 tree.Rule.prototype.eval = function (context) {
-    return new(tree.Rule)(this.name,
+    return new(tree.Rule)(this.quotedName ? this.name.eval(context) : this.name,
                           this.value.eval(context),
                           this.important,
                           this.index, this.inline);

test/css/variables.css

@@ -25,3 +25,7 @@
 a:nth-child(2) {
   border: 1px;
 }
+div {
+  -webkit-border-radius: 5px;
+  border-radius: 5px;
+}

test/less/variables.less

@@ -16,6 +16,8 @@
 @quotes: "~" "~";
 @q: @quotes;
 
+@property: "border-radius";
+
 .variables {
   height: @b + @x + 0px; // 24px
   color: @c;
@@ -52,3 +54,8 @@
 a:nth-child(@a) {
     border: 1px;
 }
+
+div {
+  ~"-webkit-@{property}": 5px;
+  ~"@{property}": 5px;
+}