diff --git a/lib/preprocess.js b/lib/preprocess.js
index 1d10bd7..65c7b6b 100644
--- a/lib/preprocess.js
+++ b/lib/preprocess.js
@@ -187,20 +187,17 @@ function preprocessor(src, context, opts, noRestoreEol) {
   });
 
   rv = replace(rv, opts.type.exec, function (match, name, value) {
-    name = (name || '').trim();
-    value = value || '';
+    var reToken = new RegExp(/^\s*(?:("|')(.*?)(?:\1\s*,?|$)|([^,]*?)\s*(?:,|$))/),
+      params = [];
 
-    var params = value.split(',');
-    var stringRegex = /^['"](.*)['"]$/;
+    function token2param(s, q, str, prop) {
+      params.push(typeof str !== 'undefined' ? str : getDeepPropFromObj(context, prop));
+      return '';
+    }
 
-    params = params.map(function(param){
-      param = param.trim();
-      if (stringRegex.test(param)) { // handle string parameter
-        return param.replace(stringRegex, '$1');
-      } else { // handle variable parameter
-        return getDeepPropFromObj(context, param);
-      }
-    });
+    name = (name || '').trim();
+    value = value == null ? ' ' : value + ' '; // space for end of comma
+    while (value.length) { value = value.replace(reToken, token2param); }
 
     var fn = getDeepPropFromObj(context, name);
     if (!fn || typeof fn !== 'function') return '';