implement exports, fixes #141

lib/src/codegen/js_printer.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dev_compiler.src.codegen.js_printer;
 
-import 'dart:io' show Directory, File;
+import 'dart:io' show Directory, File, Platform, Process;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:path/path.dart' as path;
 import 'package:source_maps/source_maps.dart' as srcmaps show Printer;
 import 'package:source_maps/source_maps.dart' show SourceMapSpan;
 import 'package:source_span/source_span.dart' show SourceLocation;
 
 import 'package:dev_compiler/src/js/js_ast.dart' as JS;
 import 'package:dev_compiler/src/utils.dart'
     show computeHash, locationForOffset;
 
@@ skipping 23 matching lines @@
   if (context is SourceMapPrintingContext) {
     var printer = context.printer;
     printer.add('//# sourceMappingURL=$outFilename.map');
     // Write output file and source map
     text = printer.text;
     new File('$outputPath.map').writeAsStringSync(printer.map);
   } else {
     text = (context as JS.SimpleJavaScriptPrintingContext).getText();
   }
   new File(outputPath).writeAsStringSync(text);
+  if (jsTree.scriptTag != null) {
+    // Mark executable.
+    // TODO(jmesserly): should only do this if the input file was executable?
+    if (!Platform.isWindows) Process.runSync('chmod', ['+x', outputPath]);
+  }
+
   return computeHash(text);
 }
 
 class SourceMapPrintingContext extends JS.JavaScriptPrintingContext {
   final srcmaps.Printer printer;
   final String outputDir;
 
   CompilationUnit unit;
   Uri uri;
 
@@ skipping 42 matching lines @@
 
     // TODO(jmesserly): in many cases marking the end will be unnecessary.
     printer.mark(_location(node.end));
   }
 
   String _getIdentifier(AstNode node) {
     if (node is SimpleIdentifier) return node.name;
     return null;
   }
 }