Action AST node no longer accepts functions as actions (only strings).

lib/compiler.js

@@ -993,23 +993,19 @@ PEG.Grammar.RuleRef.prototype.compile = function(resultVar) {
 PEG.Grammar.Action.prototype.compile = function(resultVar) {
   var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
 
-  if (typeof(this._action) === "function") {
-    var actionFunction = this._action.toString();
-  } else {
-    var actionCode = this._action.replace(
-      /\$(\d+)/g,
-      function(match, digits) {
-        return PEG.Compiler.formatCode(
-          "(arguments[${index}])",
-          { index: parseInt(digits) - 1 }
-        );
-      }
-    )
-    var actionFunction = PEG.Compiler.formatCode(
-      "function() { ${actionCode} }",
-      { actionCode: actionCode }
-    );
-  }
+  var actionCode = this._action.replace(
+    /\$(\d+)/g,
+    function(match, digits) {
+      return PEG.Compiler.formatCode(
+        "(arguments[${index}])",
+        { index: parseInt(digits) - 1 }
+      );
+    }
+  )
+  var actionFunction = PEG.Compiler.formatCode(
+    "function() { ${actionCode} }",
+    { actionCode: actionCode }
+  );
 
   /*
    * In case of sequences, we splat their elements into function arguments one