[modules] Basic support of exports

test/mjsunit/modules/export1.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// MODULE
+
+export var myvar = "var";
+assertEquals("var", myvar);
+assertEquals("var", eval("myvar"));
+(() => assertEquals("var", myvar))();
+
+export let mylet = "let";
+assertEquals("let", mylet);
+assertEquals("let", eval("mylet"));
+(() => assertEquals("let", mylet))();
+
+export const myconst = "const";
+assertEquals("const", myconst);
+assertEquals("const", eval("myconst"));
+(() => assertEquals("const", myconst))();
+
+myvar = 1;
+assertEquals(1, myvar);
+assertEquals(1, eval("myvar"));
+(() => assertEquals(1, myvar))();
+(() => myvar = 2)();
+assertEquals(2, myvar);
+(() => assertEquals(2, myvar))();
+
+mylet = 1;
+assertEquals(1, mylet);
+assertEquals(1, eval("mylet"));
+(() => assertEquals(1, mylet))();
+(() => mylet = 2)();
+assertEquals(2, mylet);
+assertEquals(2, eval("mylet"));
+(() => assertEquals(2, mylet))();
+let ooo = () => assertEquals(2, mylet);
+ooo();
+
+assertThrows(() => myconst = 1, TypeError);
+assertEquals("const", myconst);
+assertEquals("const", eval("myconst"));
+(() => assertEquals("const", myconst))();