Starting destructuring.

lib/parse.js

@@ -644,6 +644,7 @@ function parse($TEXT, options) {
         prev          : null,
         peeked        : null,
         in_function   : 0,
+        in_parameters : false,
         in_directives : true,
         in_loop       : 0,
         labels        : []
@@ -957,35 +958,58 @@ function parse($TEXT, options) {
     };
 
     var function_ = function(ctor) {
+        var start = S.token
+
         var in_statement = ctor === AST_Defun;
         var name = is("name") ? as_symbol(in_statement ? AST_SymbolDefun : AST_SymbolLambda) : null;
         if (in_statement && !name)
             unexpected();
-        expect("(");
+
+        var args = params_or_seq_().as_params(croak);
+        var body = _function_body();
         return new ctor({
-            name: name,
-            argnames: (function(first, a){
-                while (!is("punc", ")")) {
-                    if (first) first = false; else expect(",");
-                    a.push(as_symbol(AST_SymbolFunarg));
-                }
-                next();
-                return a;
-            })(true, []),
-            body: (function(loop, labels){
-                ++S.in_function;
-                S.in_directives = true;
-                S.in_loop = 0;
-                S.labels = [];
-                var a = block_();
-                --S.in_function;
-                S.in_loop = loop;
-                S.labels = labels;
-                return a;
-            })(S.in_loop, S.labels)
+            start : args.start,
+            end   : body.end,
+            name  : name,
+            argnames: args,
+            body  : body
         });
     };
 
+    function params_or_seq_() {
+        var start = S.token
+        expect("(");
+        var first = true;
+        var a = [];
+        S.in_parameters = true;
+        while (!is("punc", ")")) {
+            if (first) first = false; else expect(",");
+            a.push(expression(false));
+        }
+        S.in_parameters = false;
+        var end = S.token
+        next();
+        return new AST_ArrowParametersOrSeq({
+            start: start,
+            end: end,
+            expressions: a
+        });
+    }
+
+    function _function_body() {
+        var loop = S.in_loop;
+        var labels = S.labels;
+        ++S.in_function;
+        S.in_directives = true;
+        S.in_loop = 0;
+        S.labels = [];
+        var a = block_();
+        --S.in_function;
+        S.in_loop = loop;
+        S.labels = labels;
+        return a;
+    }
+
     function if_() {
         var cond = parenthesised(), body = statement(), belse = null;
         if (is("keyword", "else")) {
@@ -1224,6 +1248,7 @@ function parse($TEXT, options) {
     });
 
     var object_ = embed_tokens(function() {
+        var start = S.token;
         expect("{");
         var first = true, a = [];
         while (!is("punc", "}")) {
@@ -1254,14 +1279,33 @@ function parse($TEXT, options) {
                     continue;
                 }
             }
-            expect(":");
-            a.push(new AST_ObjectKeyVal({
-                start : start,
-                quote : start.quote,
-                key   : name,
-                value : expression(false),
-                end   : prev()
-            }));
+
+            if (!is("punc", ":")) {
+                // It's one of those object destructurings, the value is its own name
+                if (!S.in_parameters) {
+                    croak("Invalid syntax", S.token.line, S.token.col);
+                }
+                a.push(new AST_ObjectSymbol({
+                    start: start,
+                    end: start,
+                    symbol: new AST_SymbolRef({
+                        start: start,
+                        end: start,
+                        name: name
+                    })
+                }));
+            } else {
+                if (S.in_parameters) {
+                    croak("Cannot destructure", S.token.line, S.token.col);
+                }
+                expect(":");
+                a.push(new AST_ObjectKeyVal({
+                    start : start,
+                    key   : name,
+                    value : expression(false),
+                    end   : prev()
+                }));
+            }
         }
         next();
         return new AST_Object({ properties: a });