Implement harmony generators and yield

Uses #716's implementation and adds tests.

Fixes #716.

test/compress/harmony.js

@@ -418,3 +418,19 @@ regression_cannot_use_of: {
         foo();  /* Label statement missing? No prob. */
     }
 }
+
+generators: {
+    input: {
+        function* fn() {};
+    }
+    expect_exact: "function*fn(){}"
+}
+
+generators_yield: {
+    input: {
+      function* fn() {
+        yield remote();
+      }
+    }
+    expect_exact: "function*fn(){yield remote()}"
+}

test/parser.js

@@ -118,6 +118,17 @@ module.exports = function () {
     ok.equal(expanding_def.name.names[0].TYPE, 'SymbolVar');
     ok.equal(expanding_def.name.names[1].TYPE, 'Expansion');
     ok.equal(expanding_def.name.names[1].symbol.TYPE, 'SymbolVar');
+
+    // generators
+    var generators_def = UglifyJS.parse('function* fn() {}').body[0];
+    ok.equal(generators_def.is_generator, true);
+
+    ok.throws(function () {
+        UglifyJS.parse('function* (){ }');
+    });
+
+    var generators_yield_def = UglifyJS.parse('function* fn() {\nyield remote();\}').body[0].body[0];
+    ok.equal(generators_yield_def.body.operator, 'yield');
 }
 
 // Run standalone