fix #606, allow specifying the summary file extension

lib/src/compiler/compiler.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:collection' show HashSet;
 import 'package:args/args.dart' show ArgParser, ArgResults;
 import 'package:args/src/usage_exception.dart' show UsageException;
 import 'package:analyzer/analyzer.dart'
     show
         AnalysisError,
@@ skipping 140 matching lines @@
 
   /// If [sourceMap] is emitted, this will emit a `sourceMappingUrl` comment
   /// into the output JavaScript module.
   final bool sourceMapComment;
 
   /// Whether to emit a summary file containing API signatures.
   ///
   /// This is required for a modular build process.
   final bool summarizeApi;
 
+  /// The file extension for summaries.
+  final String summaryExtension;
+
   /// Whether to preserve metdata only accessible via mirrors
   final bool emitMetadata;
 
   /// Whether to force compilation of code with static errors.
   final bool unsafeForceCompile;
 
   /// Whether to emit Closure Compiler-friendly code.
   final bool closure;
 
   /// Hoist the types at instance creation sites
@@ skipping 27 matching lines @@
   final bool destructureNamedParams;
 
   /// Which module format to support.
   /// Currently 'es6' and 'legacy' are supported.
   final ModuleFormat moduleFormat;
 
   const CompilerOptions(
       {this.sourceMap: true,
       this.sourceMapComment: true,
       this.summarizeApi: true,
+      this.summaryExtension: 'sum',
       this.unsafeForceCompile: false,
       this.emitMetadata: false,
       this.closure: false,
       this.destructureNamedParams: false,
       this.moduleFormat: ModuleFormat.legacy,
       this.hoistInstanceCreation: true,
       this.hoistSignatureTypes: false,
       this.nameTypeTests: true,
       this.hoistTypeTests: true,
       this.useAngular2Whitelist: false});
 
   CompilerOptions.fromArguments(ArgResults args)
       : sourceMap = args['source-map'],
         sourceMapComment = args['source-map-comment'],
         summarizeApi = args['summarize'],
+        summaryExtension = args['summary-extension'],
         unsafeForceCompile = args['unsafe-force-compile'],
         emitMetadata = args['emit-metadata'],
         closure = args['closure-experimental'],
         destructureNamedParams = args['destructure-named-params'],
         moduleFormat = parseModuleFormat(args['modules']),
         hoistInstanceCreation = args['hoist-instance-creation'],
         hoistSignatureTypes = args['hoist-signature-types'],
         nameTypeTests = args['name-type-tests'],
         hoistTypeTests = args['hoist-type-tests'],
         useAngular2Whitelist = args['unsafe-angular2-whitelist'];
 
   static ArgParser addArguments(ArgParser parser) => parser
     ..addFlag('summarize', help: 'emit an API summary file', defaultsTo: true)
+    ..addOption('summary-extension',
+        help: 'file extension for Dart summary files', defaultsTo: 'sum')
     ..addFlag('source-map', help: 'emit source mapping', defaultsTo: true)
     ..addFlag('source-map-comment',
         help: 'adds a sourceMappingURL comment to the end of the JS,\n'
             'disable if using X-SourceMap header',
         defaultsTo: true)
     ..addOption('modules',
         help: 'module pattern to emit',
         allowed: ['es6', 'legacy', 'node'],
         allowedHelp: {
           'es6': 'es6 modules',
@@ skipping 104 matching lines @@
   }
 }
 
 /// (Public for tests) the error code used when a part is missing.
 final missingPartErrorCode = const CompileTimeErrorCode(
     'MISSING_PART', 'The part was not supplied as an input to the compiler.');
 
 /// (Public for tests) the error code used when a part is unused.
 final unusedPartWarningCode = const StaticWarningCode(
     'UNUSED_PART', 'The part was not used by any libraries being compiled.');