Initial --modules=es6 support

lib/src/options.dart

 // Copyright (c) 2014, 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.
 
 /// Set of flags and options passed to the compiler
 library dev_compiler.src.options;
 
 import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:cli_util/cli_util.dart' show getSdkDir;
 import 'package:logging/logging.dart' show Level;
 import 'package:path/path.dart' as path;
 import 'package:yaml/yaml.dart';
 
+import 'utils.dart' show parseEnum, getEnumName;
+
 const String _V8_BINARY_DEFAULT = 'node';
 const bool _CLOSURE_DEFAULT = false;
 const bool _DESTRUCTURE_NAMED_PARAMS_DEFAULT = false;
 
 /// Options used to set up Source URI resolution in the analysis context.
 class SourceResolverOptions {
   /// Whether to resolve 'package:' uris using the multi-package resolver.
   final bool useMultiPackage;
 
   /// Custom URI mappings, such as "dart:foo" -> "path/to/foo.dart"
@@ skipping 23 matching lines @@
       {this.useMockSdk: false,
       this.dartSdkPath,
       this.useMultiPackage: false,
       this.customUrlMappings: const {},
       this.packageRoot: 'packages/',
       this.packagePaths: const <String>[],
       this.resources: const <String>[],
       this.useImplicitHtml: false});
 }
 
+enum ModuleFormat { es6, legacy }
+ModuleFormat parseModuleFormat(String s) => parseEnum(s, ModuleFormat.values);
+
 // TODO(jmesserly): refactor all codegen options here.
 class CodegenOptions {
   /// Whether to emit the source map files.
   final bool emitSourceMaps;
 
   /// Whether to force compilation of code with static errors.
   final bool forceCompile;
 
   /// Output directory for generated code.
   final String outputDir;
 
   /// Emit Closure Compiler-friendly code.
   final bool closure;
 
   /// Enable ES6 destructuring of named parameters.
   final bool destructureNamedParams;
 
   /// Whether to emit a workaround for missing arrow function bind-this in
   /// other V8 builds
   final bool arrowFnBindThisWorkaround;
 
   /// Which module format to support.
-  /// Currently 'es6' and 'dart' are supported.
-  final String moduleFormat;
+  /// Currently 'es6' and 'legacy' are supported.
+  final ModuleFormat moduleFormat;
 
   const CodegenOptions(
       {this.emitSourceMaps: true,
       this.forceCompile: false,
       this.closure: _CLOSURE_DEFAULT,
       this.destructureNamedParams: _DESTRUCTURE_NAMED_PARAMS_DEFAULT,
       this.outputDir,
       this.arrowFnBindThisWorkaround: false,
-      this.moduleFormat: 'dart'});
+      this.moduleFormat: ModuleFormat.legacy});
 }
 
 /// Options for devrun.
 class RunnerOptions {
   /// V8-based binary to be used to run the .js output (d8, iojs, node).
   /// Can be just the executable name if it's in the path, or a path to the
   /// executable.
   final String v8Binary;
 
   const RunnerOptions({this.v8Binary: _V8_BINARY_DEFAULT});
@@ skipping 49 matching lines @@
   /// package (if we can infer where that is located).
   final String runtimeDir;
 
   /// The files to compile.
   final List<String> inputs;
 
   /// The base directory for [inputs]. Module imports will be generated relative
   /// to this directory.
   final String inputBaseDir;
 
-  CompilerOptions(
+  const CompilerOptions(
       {this.sourceOptions: const SourceResolverOptions(),
       this.codegenOptions: const CodegenOptions(),
       this.runnerOptions: const RunnerOptions(),
       this.checkSdk: false,
       this.dumpInfo: false,
       this.htmlReport: false,
       this.dumpInfoFile,
       this.useColors: true,
       this.help: false,
       this.version: false,
@@ skipping 60 matching lines @@
   if (serverMode && args.rest.length != 1) showUsage = true;
 
   return new CompilerOptions(
       codegenOptions: new CodegenOptions(
           emitSourceMaps: args['source-maps'],
           forceCompile: args['force-compile'] || serverMode,
           closure: args['closure'],
           destructureNamedParams: args['destructure-named-params'],
           outputDir: outputDir,
           arrowFnBindThisWorkaround: args['arrow-fn-bind-this'],
-          moduleFormat: args['modules']),
+          moduleFormat: parseModuleFormat(args['modules'])),
       sourceOptions: new SourceResolverOptions(
           useMockSdk: args['mock-sdk'],
           dartSdkPath: sdkPath,
           useImplicitHtml: serverMode &&
               args.rest.length == 1 &&
               args.rest[0].endsWith('.dart'),
           customUrlMappings: customUrlMappings,
           useMultiPackage: args['use-multi-package'],
           packageRoot: args['package-root'],
           packagePaths: args['package-paths'].split(','),
@@ skipping 46 matching lines @@
   ..addOption('resources',
       help: 'Additional resources to serve', defaultsTo: '')
   ..addFlag('source-maps',
       help: 'Whether to emit source map files', defaultsTo: true)
   ..addOption('runtime-dir',
       help: 'Where to find dev_compiler\'s runtime files', defaultsTo: null)
   ..addFlag('arrow-fn-bind-this',
       help: 'Work around `this` binding in => functions')
   ..addOption('modules',
       help: 'Which module pattern to emit',
-      allowed: ['es6', 'dart'],
+      allowed: ModuleFormat.values.map(getEnumName).toList(),
       allowedHelp: {
-        'es6': 'es6 modules',
-        'custom-dart': 'a custom format used by dartdevc, similar to AMD'
+        getEnumName(ModuleFormat.es6): 'es6 modules',
+        getEnumName(ModuleFormat.legacy):
+            'a custom format used by dartdevc, similar to AMD'
       },
-      defaultsTo: 'dart')
+      defaultsTo: getEnumName(ModuleFormat.legacy))
 
   // general options
   ..addFlag('help', abbr: 'h', help: 'Display this message')
   ..addFlag('version',
       negatable: false, help: 'Display the Dev Compiler verion')
   ..addFlag('server', help: 'Run as a development server.', defaultsTo: false)
   ..addFlag('hashing',
       help: 'Enable hash-based file caching.', defaultsTo: null)
   ..addFlag('widget',
       help: 'Serve embedded widget with static errors and warnings.',
@@ skipping 78 matching lines @@
     // The pub-cache directory is two levels up, but we verify that the layout
     // looks correct.
     if (path.basename(dir) != 'dev_compiler') return null;
     dir = path.dirname(dir);
     if (path.basename(dir) != 'global_packages') return null;
     dir = path.dirname(dir);
     return path.join(dir, cacheDir, 'lib', 'runtime');
   }
   return null;
 }