fix #626, add AMD module format and make it default

lib/src/compiler/command.dart

 // Copyright (c) 2016, 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.
 
-import 'dart:convert' show JSON;
 import 'dart:io';
 import 'package:analyzer/src/generated/source.dart' show Source;
 import 'package:analyzer/src/summary/package_bundle_reader.dart'
     show InSummarySource;
 import 'package:args/args.dart' show ArgParser, ArgResults;
 import 'package:args/command_runner.dart' show UsageException;
 import 'package:path/path.dart' as path;
 
+import '../analyzer/context.dart' show AnalyzerOptions;
 import 'compiler.dart'
     show BuildUnit, CompilerOptions, JSModuleFile, ModuleCompiler;
-import '../analyzer/context.dart' show AnalyzerOptions;
+import 'module_builder.dart';
 
 final ArgParser _argParser = () {
   var argParser = new ArgParser()
     ..addFlag('help', abbr: 'h', help: 'Display this message.')
-    ..addOption('out', abbr: 'o', help: 'Output file (required).')
+    ..addOption('out',
+        abbr: 'o', allowMultiple: true, help: 'Output file (required).')
     ..addOption('module-root',
         help: 'Root module directory.\n'
             'Generated module paths are relative to this root.')
     ..addOption('library-root',
         help: 'Root of source files.\n'
             'Generated library names are relative to this root.')
     ..addOption('build-root',
         help: 'Deprecated in favor of --library-root', hide: true);
+  addModuleFormatOptions(argParser, allowMultiple: true);
   AnalyzerOptions.addArguments(argParser);
   CompilerOptions.addArguments(argParser);
   return argParser;
 }();
 
 /// Runs a single compile for dartdevc.
 ///
 /// This handles argument parsing, usage, error handling.
 /// See bin/dartdevc.dart for the actual entry point, which includes Bazel
 /// worker support.
@@ skipping 41 matching lines @@
 }
 
 void _compile(ArgResults argResults, void printFn(Object obj)) {
   var compiler =
       new ModuleCompiler(new AnalyzerOptions.fromArguments(argResults));
   var compilerOpts = new CompilerOptions.fromArguments(argResults);
   if (argResults['help']) {
     printFn(_usageMessage);
     return;
   }
-  var outPath = argResults['out'];
+  var outPaths = argResults['out'] as List<String>;
+  var moduleFormats = parseModuleFormatOption(argResults);
 
-  if (outPath == null) {
+  if (outPaths.isEmpty) {
     _usageException('Please include the output file location. For example:\n'
         '    -o PATH/TO/OUTPUT_FILE.js');
+  } else if (outPaths.length != moduleFormats.length) {
+    _usageException('Number of output files (${outPaths.length}) must match '
+        'number of module formats (${moduleFormats.length}).');
   }
 
+  // TODO(jmesserly): for now the first one is special. This will go away once
+  // we've removed the "root" and "module name" variables.
+  var outPath = outPaths[0];
+
   var libraryRoot = argResults['library-root'] as String;
   libraryRoot ??= argResults['build-root'] as String;
   if (libraryRoot != null) {
     libraryRoot = path.absolute(libraryRoot);
   } else {
     libraryRoot = Directory.current.path;
   }
   var moduleRoot = argResults['module-root'] as String;
   String modulePath;
   if (moduleRoot != null) {
@@ skipping 11 matching lines @@
 
   var unit = new BuildUnit(modulePath, libraryRoot, argResults.rest,
       (source) => _moduleForLibrary(moduleRoot, source, compilerOpts));
 
   JSModuleFile module = compiler.compile(unit, compilerOpts);
   module.errors.forEach(printFn);
 
   if (!module.isValid) throw new CompileErrorException();
 
   // Write JS file, as well as source map and summary (if requested).
-  new File(outPath).writeAsStringSync(module.code);
-  if (module.sourceMap != null) {
-    var mapPath = outPath + '.map';
-    new File(mapPath)
-        .writeAsStringSync(JSON.encode(module.placeSourceMap(mapPath)));
+  for (int i = 0; i < outPaths.length; i++) {

[nweiz, 2016/08/24 23:33:26]

Nit: "var i"

+    module.writeCodeSync(moduleFormats[i], outPaths[i]);
   }
+
+  // TODO(jmesserly): should we write the summary next to every output?

[nweiz, 2016/08/24 23:33:26]

IMO, yes. The extra time is likely to be negligible, and the ecosystem value of
knowing that every JS file has a corresponding summary will probably be high.

[Jennifer Messerly, 2016/08/25 16:21:39]

good idea. done!

   if (module.summaryBytes != null) {
     var summaryPath =
         path.withoutExtension(outPath) + '.${compilerOpts.summaryExtension}';
     new File(summaryPath).writeAsBytesSync(module.summaryBytes);
   }
 }
 
 String _moduleForLibrary(
     String moduleRoot, Source source, CompilerOptions compilerOpts) {
   if (source is InSummarySource) {
@@ skipping 21 matching lines @@
     '\n\n${_argParser.usage}';
 
 void _usageException(String message) {
   throw new UsageException(message, _usageMessage);
 }
 
 /// Thrown when the input source code has errors.
 class CompileErrorException implements Exception {
   toString() => '\nPlease fix all errors before compiling (warnings are okay).';
 }