Easier to read font regexp

lib/canvas.js

@@ -42,10 +42,24 @@ exports.cairoVersion = cairoVersion;
 var cache = {};
 
 /**
- * Font RegExp used by parseFont();
+ * Font RegExp helpers.
  */
 
-var font = /^ *(?:(normal|bold|bolder|lighter|[1-9](?:00)) *)?(?:(normal|italic|oblique) *)?(\d+)(px|pt|pc|in|cm|mm|%) *((?:"([^"]+)"|[\w-]+)( *, *(?:"([^"]+)"|[\w-]+))*)/;
+var weights = 'normal|bold|bolder|lighter|[1-9](?:00)'
+  , styles = 'normal|italic|oblique'
+  , units = 'px|pt|pc|in|cm|mm|%'
+  , string = '"([^"]+)"|[\\w-]+';
+
+/**
+ * Font parser RegExp;
+ */
+
+var font = new RegExp('^ *'
+  + '(?:(' + weights + ') *)?'
+  + '(?:(' + styles + ') *)?'
+  + '(\\d+)(' + units + ') *'
+  + '((?:' + string + ')( *, *(?:' + string + '))*)'
+  );
 
 /**
  * Buffer extensions.