simple visitor API and code to figure out scope and references

1 files changed, 30 insertions, 21 deletions

diff --git a/lib/parse.js b/lib/parse.js
index f5796b0f..78b8bb7c 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -836,7 +836,14 @@ function parse($TEXT, exigent_mode) {
     });
 
     function labeled_statement() {
-        var label = as_symbol(true);
+        var label = as_symbol(AST_Label);
+        if (find_if(function(l){ return l.name == label.name }, S.labels)) {
+            // ECMA-262, 12.12: An ECMAScript program is considered
+            // syntactically incorrect if it contains a
+            // LabelledStatement that is enclosed by a
+            // LabelledStatement with the same Identifier as label.
+            croak("Label " + label.name + " defined twice");
+        }
         expect(":");
         S.labels.push(label);
         var start = S.token, stat = statement();
@@ -849,16 +856,13 @@ function parse($TEXT, exigent_mode) {
     };
 
     function break_cont(type) {
-        var name = null, label = null;
+        var label = null;
         if (!can_insert_semicolon()) {
-            name = is("name") ? S.token.value : null;
+            label = as_symbol(AST_LabelRef, true);
         }
-        if (name != null) {
-            next();
-            label = find_if(function(l){ return l.name == name }, S.labels);
-            if (!label)
-                croak("Label " + name + " without matching loop or statement");
-            label = new AST_Label({ name: name, symbol: label });
+        if (label != null) {
+            if (!find_if(function(l){ return l.name == label.name }, S.labels))
+                croak("Undefined label " + label.name);
         }
         else if (S.in_loop == 0)
             croak(type.TYPE + " not inside a loop or switch");
@@ -910,7 +914,9 @@ function parse($TEXT, exigent_mode) {
     };
 
     var function_ = function(in_statement) {
-        var name = is("name") ? as_symbol(true) : null;
+        var name = is("name") ? as_symbol(in_statement
+                                          ? AST_SymbolDefun
+                                          : AST_SymbolLambda) : null;
         if (in_statement && !name)
             unexpected();
         expect("(");
@@ -920,7 +926,7 @@ function parse($TEXT, exigent_mode) {
             argnames: (function(first, a){
                 while (!is("punc", ")")) {
                     if (first) first = false; else expect(",");
-                    a.push(as_symbol(true));
+                    a.push(as_symbol(AST_SymbolFunarg));
                 }
                 next();
                 return a;
@@ -1010,7 +1016,7 @@ function parse($TEXT, exigent_mode) {
             var start = S.token;
             next();
             expect("(");
-            var name = as_symbol(true);
+            var name = as_symbol(AST_SymbolCatch);
             expect(")");
             bcatch = new AST_Catch({
                 start   : start,
@@ -1050,7 +1056,7 @@ function parse($TEXT, exigent_mode) {
         for (;;) {
             a.push(new AST_VarDef({
                 start : S.token,
-                name  : as_symbol(true),
+                name  : as_symbol(AST_SymbolVar),
                 value : is("operator", "=") ? (next(), expression(false, no_in)) : null,
                 end   : prev()
             }));
@@ -1099,7 +1105,7 @@ function parse($TEXT, exigent_mode) {
         var tok = S.token, ret;
         switch (tok.type) {
           case "name":
-            return as_symbol();
+            return as_symbol(AST_SymbolRef);
           case "num":
             ret = new AST_Number({ start: tok, end: tok, value: tok.value });
             break;
@@ -1198,8 +1204,8 @@ function parse($TEXT, exigent_mode) {
                 if (name == "get") {
                     a.push(new AST_ObjectGetter({
                         start : start,
-                        name  : name,
-                        func  : function_(false),
+                        key   : name,
+                        value : function_(false),
                         end   : prev()
                     }));
                     continue;
@@ -1207,8 +1213,8 @@ function parse($TEXT, exigent_mode) {
                 if (name == "set") {
                     a.push(new AST_ObjectSetter({
                         start : start,
-                        name  : name,
-                        func  : function_(false),
+                        key   : name,
+                        value : function_(false),
                         end   : prev()
                     }));
                     continue;
@@ -1252,10 +1258,13 @@ function parse($TEXT, exigent_mode) {
         }
     };
 
-    function as_symbol(def) {
-        if (!is("name")) croak("Name expected");
+    function as_symbol(type, noerror) {
+        if (!is("name")) {
+            if (!noerror) croak("Name expected");
+            return null;
+        }
         var name = S.token.value;
-        var sym = new (name == "this" ? AST_This : def ? AST_Symbol : AST_SymbolRef)({
+        var sym = new (name == "this" ? AST_This : type)({
             name  : String(S.token.value),
             start : S.token,
             end   : S.token