Make parser accessible in postprocessing rules

As first suggested here: #203

Author: swwu

lib/nearley.js

@@ -63,9 +63,9 @@
         return children;
     };
 
-    State.prototype.finish = function() {
+    State.prototype.finish = function(parser) {
         if (this.rule.postprocess) {
-            this.data = this.rule.postprocess(this.data, this.reference, Parser.fail);
+            this.data = this.rule.postprocess(this.data, this.reference, Parser.fail, parser);
         }
     };
 
@@ -80,7 +80,7 @@
     }
 
 
-    Column.prototype.process = function(nextColumn) {
+    Column.prototype.process = function(parser) {
         var states = this.states;
         var wants = this.wants;
         var completed = this.completed;
@@ -89,7 +89,7 @@
             var state = states[w];
 
             if (state.isComplete) {
-                state.finish();
+                state.finish(parser);
                 if (state.data !== Parser.fail) {
                     // complete
                     var wantedBy = state.wantedBy;
@@ -269,7 +269,7 @@
         column.wants[grammar.start] = [];
         column.predict(grammar.start);
         // TODO what if start rule is nullable?
-        column.process();
+        column.process(this);
         this.current = 0; // token index
     }
 
@@ -335,7 +335,7 @@
             // To prevent duplication, we also keep track of rules we have already
             // added
 
-            nextColumn.process();
+            nextColumn.process(this);
 
             // If needed, throw an error:
             if (nextColumn.states.length === 0) {