add source maps support, fixes #50

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 ddc.src.options;
 
 import 'dart:io';
 
 import 'package:args/args.dart';
@@ skipping 61 matching lines @@
   /// Whether to inject casts between Dart assignable types.
   final bool relaxedCasts;
 
   /// Whether to use static types for code generation.
   final bool ignoreTypes;
 
   RulesOptions({this.allowConstCasts: true, this.covariantGenerics: true,
       this.relaxedCasts: true, this.ignoreTypes: false});
 }
 
+class JSCodeOptions {
+  /// Whether to emit the source map files.
+  final bool emitSourceMaps;
+
+  JSCodeOptions({this.emitSourceMaps: true});
+}
+
 /// General options used by the dev compiler.
-class CompilerOptions implements RulesOptions, ResolverOptions {
+class CompilerOptions implements RulesOptions, ResolverOptions, JSCodeOptions {
   /// Whether to check the sdk libraries.
   final bool checkSdk;
 
   /// Whether to dump summary information on the console.
   final bool dumpInfo;
 
   /// If not null, path to a file that will store a json representation of the
   /// summary information (only used if [dumpInfo] is true).
   final String dumpInfoFile;
 
@@ skipping 79 matching lines @@
   final bool onlyInferConstsAndFinalFields;
 
   /// List of non-nullable types.
   @override
   final List<String> nonnullableTypes;
 
   /// Whether to use static types for code generation.
   @override
   final bool ignoreTypes;
 
+  /// Whether to emit the source map files.
+  @override
+  final bool emitSourceMaps;
+
   CompilerOptions({this.allowConstCasts: true, this.checkSdk: false,
       this.dumpInfo: false, this.dumpInfoFile, this.dumpSrcDir,
       this.forceCompile: false, this.formatOutput: false,
       this.cheapTestFormat: false, this.ignoreTypes: false, this.outputDir,
       this.outputDart: false, this.useColors: true,
       this.covariantGenerics: true, this.relaxedCasts: true,
       this.useMultiPackage: false, this.packageRoot: 'packages/',
       this.packagePaths: const <String>[], this.inferFromOverrides: true,
       this.inferStaticsFromIdentifiers: false,
       this.inferInNonStableOrder: false,
       this.onlyInferConstsAndFinalFields: false,
       this.nonnullableTypes: TypeOptions.NONNULLABLE_TYPES, this.help: false,
       this.useMockSdk: false, this.dartSdkPath, this.logLevel: Level.SEVERE,
-      this.entryPointFile: null});
+      this.emitSourceMaps: true, this.entryPointFile: null});
 }
 
 /// Parses options from the command-line
 CompilerOptions parseOptions(List<String> argv) {
   ArgResults args = argParser.parse(argv);
   var levelName = args['log'].toUpperCase();
   var useColors = stdioType(stdout) == StdioType.TERMINAL;
   var sdkPath = args['dart-sdk'];
   if (sdkPath == null && !args['mock-sdk']) {
     sdkPath = getSdkDir(argv).path;
@@ skipping 19 matching lines @@
       inferStaticsFromIdentifiers: args['infer-transitively'],
       inferInNonStableOrder: args['infer-eagerly'],
       onlyInferConstsAndFinalFields: args['infer-only-finals'],
       nonnullableTypes: optionsToList(args['nonnullable'],
           defaultValue: TypeOptions.NONNULLABLE_TYPES),
       help: args['help'],
       useMockSdk: args['mock-sdk'],
       dartSdkPath: sdkPath,
       logLevel: Level.LEVELS.firstWhere((Level l) => l.name == levelName,
           orElse: () => Level.SEVERE),
+      emitSourceMaps: args['source-maps'],
       entryPointFile: args.rest.length == 0 ? null : args.rest.first);
 }
 
 final ArgParser argParser = new ArgParser()
   // resolver/checker options
   ..addFlag('allow-const-casts',
       help: 'Allow casts in const contexts', defaultsTo: true)
   ..addFlag('sdk-check',
       abbr: 's', help: 'Typecheck sdk libs', defaultsTo: false)
   ..addFlag('mock-sdk',
@@ skipping 31 matching lines @@
   ..addOption('dump-src-to', help: 'Dump dart src code', defaultsTo: null)
   ..addOption('package-root',
       abbr: 'p',
       help: 'Package root to resolve "package:" imports',
       defaultsTo: 'packages/')
   ..addFlag('use-multi-package',
       help: 'Whether to use the multi-package resolver for "package:" imports',
       defaultsTo: false)
   ..addOption('package-paths', help: 'if using the multi-package resolver, '
       'the list of directories where to look for packages.', defaultsTo: '')
+  ..addFlag('source-maps',
+      help: 'Whether to emit source map files', defaultsTo: true)
 
   // general options
   ..addFlag('help', abbr: 'h', help: 'Display this message')
   ..addFlag('force-compile',
       help: 'Compile code with static errors', defaultsTo: false)
   ..addOption('log', abbr: 'l', help: 'Logging level', defaultsTo: 'severe')
   ..addFlag('dump-info',
       abbr: 'i', help: 'Dump summary information', defaultsTo: false)
   ..addOption('dump-info-file',
       abbr: 'f',
       help: 'Dump info json file (requires dump-info)',
       defaultsTo: null);