lib/compiler/implementation/dart2js.dart - sdk.git - Git at Google

 // Copyright (c) 2012, 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('dart2js');

 #import('dart:io');
 #import('dart:uri');
 #import('dart:utf');

 #import('../compiler.dart', prefix: 'api');
 #import('colors.dart', prefix: 'colors');
 #import('source_file.dart');
 #import('filenames.dart');
 #import('util/uri_extras.dart');

 const String LIBRARY_ROOT = '../../../..';
 const String OUTPUT_LANGUAGE_DART = 'Dart';

 typedef void HandleOption(String option);

 class OptionHandler {
   String pattern;
   HandleOption handle;

   OptionHandler(this.pattern, this.handle);
 }

 /**
  * Extract the parameter of an option.
  *
  * For example, in ['--out=fisk.js'] and ['-ohest.js'], the parameters
  * are ['fisk.js'] and ['hest.js'], respectively.
  */
 String extractParameter(String argument) {
   // m[0] is the entire match (which will be equal to argument). m[1]
   // is something like "-o" or "--out=", and m[2] is the parameter.
   Match m = const RegExp('^(-[a-z]|--.+=)(.*)').firstMatch(argument);
   if (m == null) helpAndFail('Error: Unknown option "$argument".');
   return m[2];
 }

 String extractPath(String argument) {
   String path = nativeToUriPath(extractParameter(argument));
   return path.endsWith("/") ? path : "$path/";
 }

 void parseCommandLine(List<OptionHandler> handlers, List<String> argv) {
   // TODO(ahe): Use ../../args/args.dart for parsing options instead.
   var patterns = <String>[];
   for (OptionHandler handler in handlers) {
     patterns.add(handler.pattern);
   }
   var pattern = new RegExp('^(${Strings.join(patterns, ")\$|(")})\$');
   OUTER: for (String argument in argv) {
     Match match = pattern.firstMatch(argument);
     assert(match.groupCount == handlers.length);
     for (int i = 0; i < handlers.length; i++) {
       if (match[i + 1] != null) {
         handlers[i].handle(argument);
         continue OUTER;
       }
     }
     throw 'Internal error: "$argument" did not match';
   }
 }

 void compile(List<String> argv) {
   bool isWindows = (Platform.operatingSystem == 'windows');
   Uri cwd = getCurrentDirectory();
   bool throwOnError = false;
   bool showWarnings = true;
   bool verbose = false;
   Uri libraryRoot = cwd;
   Uri out = cwd.resolve('out.js');
   Uri sourceMapOut = cwd.resolve('out.js.map');
   Uri packageRoot = null;
   List<String> options = new List<String>();
   bool explicitOut = false;
   bool wantHelp = false;
   bool enableColors = false;
   String outputLanguage = 'JavaScript';
   bool stripArgumentSet = false;

   passThrough(String argument) => options.add(argument);

   setLibraryRoot(String argument) {
     libraryRoot = cwd.resolve(extractPath(argument));
   }

   setPackageRoot(String argument) {
     packageRoot = cwd.resolve(extractPath(argument));
   }

   setOutput(String argument) {
     explicitOut = true;
     out = cwd.resolve(nativeToUriPath(extractParameter(argument)));
     sourceMapOut = new Uri.fromString('$out.map');
   }

   setOutputType(String argument) {
     if (argument == '--output-type=dart') {
       outputLanguage = OUTPUT_LANGUAGE_DART;
       if (!explicitOut) {
         out = cwd.resolve('out.dart');
         sourceMapOut = cwd.resolve('out.dart.map');
       }
     }
     passThrough(argument);
   }

   setStrip(String argument) {
     stripArgumentSet = true;
     passThrough(argument);
   }

   handleShortOptions(String argument) {
     var shortOptions = argument.substring(1).splitChars();
     for (var shortOption in shortOptions) {
       switch (shortOption) {
         case 'v':
           verbose = true;
           break;
         case 'h':
         case '?':
           wantHelp = true;
           break;
         case 'c':
           passThrough('--enable-checked-mode');
           break;
         default:
           throw 'Internal error: "$shortOption" did not match';
       }
     }
   }

   List<String> arguments = <String>[];
   List<OptionHandler> handlers = <OptionHandler>[
     new OptionHandler('-[chv?]+', handleShortOptions),
     new OptionHandler('--throw-on-error', (_) => throwOnError = true),
     new OptionHandler('--suppress-warnings', (_) => showWarnings = false),
     new OptionHandler('--output-type=dart|--output-type=js', setOutputType),
     new OptionHandler('--verbose', (_) => verbose = true),
     new OptionHandler('--library-root=.+', setLibraryRoot),
     new OptionHandler('--out=.+|-o.+', setOutput),
     new OptionHandler('--allow-mock-compilation', passThrough),
     new OptionHandler('--minify', passThrough),
     new OptionHandler('--force-strip=.*', setStrip),
     // TODO(ahe): Remove the --no-colors option.
     new OptionHandler('--disable-diagnostic-colors',
                       (_) => enableColors = false),
     new OptionHandler('--enable-diagnostic-colors', (_) => enableColors = true),
     new OptionHandler('--enable[_-]checked[_-]mode|--checked',
                       (_) => passThrough('--enable-checked-mode')),
     new OptionHandler('--enable-concrete-type-inference',
                       (_) => passThrough('--enable-concrete-type-inference')),
     new OptionHandler(r'--help|/\?|/h', (_) => wantHelp = true),
     new OptionHandler('--package-root=.+|-p.+', setPackageRoot),
     new OptionHandler('--disallow-unsafe-eval', passThrough),
     // The following two options must come last.
     new OptionHandler('-.*', (String argument) {
       helpAndFail('Error: Unknown option "$argument".');
     }),
     new OptionHandler('.*', (String argument) {
       arguments.add(nativeToUriPath(argument));
     })
   ];

   parseCommandLine(handlers, argv);
   if (wantHelp) helpAndExit(verbose);

   if (outputLanguage != OUTPUT_LANGUAGE_DART && stripArgumentSet) {
     helpAndFail('Error: --force-strip may only be used with '
         '--output-type=dart');
   }
   if (arguments.isEmpty) {
     helpAndFail('Error: No Dart file specified.');
   }
   if (arguments.length > 1) {
     var extra = arguments.getRange(1, arguments.length - 1);
     helpAndFail('Error: Extra arguments: ${Strings.join(extra, " ")}');
   }

   Map<String, SourceFile> sourceFiles = <String, SourceFile>{};
   int dartBytesRead = 0;

   Future<String> provider(Uri uri) {
     if (uri.scheme != 'file') {
       throw new ArgumentError(uri);
     }
     String source;
     try {
       source = readAll(uriPathToNative(uri.path));
     } on FileIOException catch (ex) {
       throw 'Error: Cannot read "${relativize(cwd, uri, isWindows)}" '
             '(${ex.osError}).';
     }
     dartBytesRead += source.length;
     sourceFiles[uri.toString()] =
       new SourceFile(relativize(cwd, uri, isWindows), source);
     return new Future.immediate(source);
   }

   void info(var message, [api.Diagnostic kind = api.Diagnostic.VERBOSE_INFO]) {
     if (!verbose && identical(kind, api.Diagnostic.VERBOSE_INFO)) return;
     if (enableColors) {
       print('${colors.green("info:")} $message');
     } else {
       print('info: $message');
     }
   }

   bool isAborting = false;

   final int FATAL = api.Diagnostic.CRASH.ordinal | api.Diagnostic.ERROR.ordinal;
   final int INFO =
       api.Diagnostic.INFO.ordinal | api.Diagnostic.VERBOSE_INFO.ordinal;

   void handler(Uri uri, int begin, int end, String message,
                api.Diagnostic kind) {
     if (identical(kind.name, 'source map')) {
       // TODO(podivilov): We should find a better way to return source maps from
       // emitter. Using diagnostic handler for that purpose is a temporary hack.
       writeString(sourceMapOut, message);
       return;
     }

     if (isAborting) return;
     isAborting = identical(kind, api.Diagnostic.CRASH);
     bool fatal = (kind.ordinal & FATAL) != 0;
     bool isInfo = (kind.ordinal & INFO) != 0;
     if (isInfo && uri == null && !identical(kind, api.Diagnostic.INFO)) {
       info(message, kind);
       return;
     }
     var color;
     if (!enableColors) {
       color = (x) => x;
     } else if (identical(kind, api.Diagnostic.ERROR)) {
       color = colors.red;
     } else if (identical(kind, api.Diagnostic.WARNING)) {
       color = colors.magenta;
     } else if (identical(kind, api.Diagnostic.LINT)) {
       color = colors.magenta;
     } else if (identical(kind, api.Diagnostic.CRASH)) {
       color = colors.red;
     } else if (identical(kind, api.Diagnostic.INFO)) {
       color = colors.green;
     } else {
       throw 'Unknown kind: $kind (${kind.ordinal})';
     }
     if (uri == null) {
       assert(fatal);
       print(color(message));
     } else if (fatal || showWarnings) {
       SourceFile file = sourceFiles[uri.toString()];
       if (file == null) {
         throw '$uri: file is null';
       }
       print(file.getLocationMessage(color(message), begin, end, true, color));
     }
     if (fatal && throwOnError) {
       isAborting = true;
       throw new AbortLeg(message);
     }
   }

   Uri uri = cwd.resolve(arguments[0]);
   if (packageRoot == null) {
     packageRoot = uri.resolve('./packages/');
   }

   info('package root is $packageRoot');

   // TODO(ahe): We expect the future to be complete and call value
   // directly. In effect, we don't support truly asynchronous API.
   String code = api.compile(uri, libraryRoot, packageRoot, provider, handler,
                             options).value;
   if (code == null) {
     fail('Error: Compilation failed.');
   }
   String sourceMapFileName =
       sourceMapOut.path.substring(sourceMapOut.path.lastIndexOf('/') + 1);
   code = '$code\n//@ sourceMappingURL=${sourceMapFileName}';
   writeString(out, code);
   int bytesWritten = code.length;
   info('compiled $dartBytesRead bytes Dart -> $bytesWritten bytes '
        '$outputLanguage in ${relativize(cwd, out, isWindows)}');
   if (!explicitOut) {
     String input = uriPathToNative(arguments[0]);
     String output = relativize(cwd, out, isWindows);
     print('Dart file $input compiled to $outputLanguage: $output');
   }
 }

 class AbortLeg {
   final message;
   AbortLeg(this.message);
   toString() => 'Aborted due to --throw-on-error: $message';
 }

 void writeString(Uri uri, String text) {
   if (uri.scheme != 'file') {
     fail('Error: Unhandled scheme ${uri.scheme}.');
   }
   var file = new File(uriPathToNative(uri.path)).openSync(FileMode.WRITE);
   file.writeStringSync(text);
   file.closeSync();
 }

 String readAll(String filename) {
   var file = (new File(filename)).openSync(FileMode.READ);
   var length = file.lengthSync();
   var buffer = new List<int>(length);
   var bytes = file.readListSync(buffer, 0, length);
   file.closeSync();
   return new String.fromCharCodes(new Utf8Decoder(buffer).decodeRest());
 }

 void fail(String message) {
   print(message);
   exit(1);
 }

 void compilerMain(Options options) {
   var root = uriPathToNative("/$LIBRARY_ROOT");
   List<String> argv = ['--library-root=${options.script}$root'];
   argv.addAll(options.arguments);
   compile(argv);
 }

 void help() {
   // This message should be no longer than 20 lines. The default
   // terminal size normally 80x24. Two lines are used for the prompts
   // before and after running the compiler. Another two lines may be
   // used to print an error message.
   print('''
 Usage: dart2js [options] dartfile

 Compiles Dart to JavaScript.

 Common options:
   -o<file> Generate the output into <file>.
   -c       Insert runtime type checks and enable assertions (checked mode).
   -h       Display this message (add -v for information about all options).''');
 }

 void verboseHelp() {
   print('''
 Usage: dart2js [options] dartfile

 Compiles Dart to JavaScript.

 Supported options:
   -o<file>, --out=<file>
     Generate the output into <file>.

   -c, --enable-checked-mode, --checked
     Insert runtime type checks and enable assertions (checked mode).

   -h, /h, /?, --help
     Display this message (add -v for information about all options).

   -v, --verbose
     Display verbose information.

   -p<path>, --package-root=<path>
     Where to find packages, that is, "package:..." imports.

   --minify
     Generate minified output.

   --suppress-warnings
     Do not display any warnings.

   --enable-diagnostic-colors
     Add colors to diagnostic messages.

 The following options are only used for compiler development and may
 be removed in a future version:

   --output-type=dart
     Output Dart code instead of JavaScript.

   --throw-on-error
     Throw an exception if a compile-time error is detected.

   --library-root=<directory>
     Where to find the Dart platform libraries.

   --allow-mock-compilation
     Do not generate a call to main if either of the following
     libraries are used: dart:dom, dart:html dart:io.

   --enable-concrete-type-inference
     Enable experimental concrete type inference.

   --disallow-unsafe-eval
     Disables dynamic generation of code in the generated output. This is
     necessary to satisfy CSP restrictions (see http://www.w3.org/TR/CSP/).
     This flag is not continuously tested. Please report breakages and we
     will fix them as soon as possible.''');
 }

 void helpAndExit(bool verbose) {
   if (verbose) {
     verboseHelp();
   } else {
     help();
   }
   exit(0);
 }

 void helpAndFail(String message) {
   help();
   print('');
   fail(message);
 }

 void main() {
   try {
     compilerMain(new Options());
   } catch (exception, trace) {
     try {
       print('Internal error: $exception');
     } catch (ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }
	// Copyright (c) 2012, 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('dart2js');

	#import('dart:io');
	#import('dart:uri');
	#import('dart:utf');

	#import('../compiler.dart', prefix: 'api');
	#import('colors.dart', prefix: 'colors');
	#import('source_file.dart');
	#import('filenames.dart');
	#import('util/uri_extras.dart');

	const String LIBRARY_ROOT = '../../../..';
	const String OUTPUT_LANGUAGE_DART = 'Dart';

	typedef void HandleOption(String option);

	class OptionHandler {
	String pattern;
	HandleOption handle;

	OptionHandler(this.pattern, this.handle);
	}

	/**
	* Extract the parameter of an option.
	*
	* For example, in ['--out=fisk.js'] and ['-ohest.js'], the parameters
	* are ['fisk.js'] and ['hest.js'], respectively.
	*/
	String extractParameter(String argument) {
	// m[0] is the entire match (which will be equal to argument). m[1]
	// is something like "-o" or "--out=", and m[2] is the parameter.
	Match m = const RegExp('^(-[a-z]\|--.+=)(.*)').firstMatch(argument);
	if (m == null) helpAndFail('Error: Unknown option "$argument".');
	return m[2];
	}

	String extractPath(String argument) {
	String path = nativeToUriPath(extractParameter(argument));
	return path.endsWith("/") ? path : "$path/";
	}

	void parseCommandLine(List<OptionHandler> handlers, List<String> argv) {
	// TODO(ahe): Use ../../args/args.dart for parsing options instead.
	var patterns = <String>[];
	for (OptionHandler handler in handlers) {
	patterns.add(handler.pattern);
	}
	var pattern = new RegExp('^(${Strings.join(patterns, ")\$\|(")})\$');
	OUTER: for (String argument in argv) {
	Match match = pattern.firstMatch(argument);
	assert(match.groupCount == handlers.length);
	for (int i = 0; i < handlers.length; i++) {
	if (match[i + 1] != null) {
	handlers[i].handle(argument);
	continue OUTER;
	}
	}
	throw 'Internal error: "$argument" did not match';
	}
	}

	void compile(List<String> argv) {
	bool isWindows = (Platform.operatingSystem == 'windows');
	Uri cwd = getCurrentDirectory();
	bool throwOnError = false;
	bool showWarnings = true;
	bool verbose = false;
	Uri libraryRoot = cwd;
	Uri out = cwd.resolve('out.js');
	Uri sourceMapOut = cwd.resolve('out.js.map');
	Uri packageRoot = null;
	List<String> options = new List<String>();
	bool explicitOut = false;
	bool wantHelp = false;
	bool enableColors = false;
	String outputLanguage = 'JavaScript';
	bool stripArgumentSet = false;

	passThrough(String argument) => options.add(argument);

	setLibraryRoot(String argument) {
	libraryRoot = cwd.resolve(extractPath(argument));
	}

	setPackageRoot(String argument) {
	packageRoot = cwd.resolve(extractPath(argument));
	}

	setOutput(String argument) {
	explicitOut = true;
	out = cwd.resolve(nativeToUriPath(extractParameter(argument)));
	sourceMapOut = new Uri.fromString('$out.map');
	}

	setOutputType(String argument) {
	if (argument == '--output-type=dart') {
	outputLanguage = OUTPUT_LANGUAGE_DART;
	if (!explicitOut) {
	out = cwd.resolve('out.dart');
	sourceMapOut = cwd.resolve('out.dart.map');
	}
	}
	passThrough(argument);
	}

	setStrip(String argument) {
	stripArgumentSet = true;
	passThrough(argument);
	}

	handleShortOptions(String argument) {
	var shortOptions = argument.substring(1).splitChars();
	for (var shortOption in shortOptions) {
	switch (shortOption) {
	case 'v':
	verbose = true;
	break;
	case 'h':
	case '?':
	wantHelp = true;
	break;
	case 'c':
	passThrough('--enable-checked-mode');
	break;
	default:
	throw 'Internal error: "$shortOption" did not match';
	}
	}
	}

	List<String> arguments = <String>[];
	List<OptionHandler> handlers = <OptionHandler>[
	new OptionHandler('-[chv?]+', handleShortOptions),
	new OptionHandler('--throw-on-error', (_) => throwOnError = true),
	new OptionHandler('--suppress-warnings', (_) => showWarnings = false),
	new OptionHandler('--output-type=dart\|--output-type=js', setOutputType),
	new OptionHandler('--verbose', (_) => verbose = true),
	new OptionHandler('--library-root=.+', setLibraryRoot),
	new OptionHandler('--out=.+\|-o.+', setOutput),
	new OptionHandler('--allow-mock-compilation', passThrough),
	new OptionHandler('--minify', passThrough),
	new OptionHandler('--force-strip=.*', setStrip),
	// TODO(ahe): Remove the --no-colors option.
	new OptionHandler('--disable-diagnostic-colors',
	(_) => enableColors = false),
	new OptionHandler('--enable-diagnostic-colors', (_) => enableColors = true),
	new OptionHandler('--enable[_-]checked[_-]mode\|--checked',
	(_) => passThrough('--enable-checked-mode')),
	new OptionHandler('--enable-concrete-type-inference',
	(_) => passThrough('--enable-concrete-type-inference')),
	new OptionHandler(r'--help\|/\?\|/h', (_) => wantHelp = true),
	new OptionHandler('--package-root=.+\|-p.+', setPackageRoot),
	new OptionHandler('--disallow-unsafe-eval', passThrough),
	// The following two options must come last.
	new OptionHandler('-.*', (String argument) {
	helpAndFail('Error: Unknown option "$argument".');
	}),
	new OptionHandler('.*', (String argument) {
	arguments.add(nativeToUriPath(argument));
	})
	];

	parseCommandLine(handlers, argv);
	if (wantHelp) helpAndExit(verbose);

	if (outputLanguage != OUTPUT_LANGUAGE_DART && stripArgumentSet) {
	helpAndFail('Error: --force-strip may only be used with '
	'--output-type=dart');
	}
	if (arguments.isEmpty) {
	helpAndFail('Error: No Dart file specified.');
	}
	if (arguments.length > 1) {
	var extra = arguments.getRange(1, arguments.length - 1);
	helpAndFail('Error: Extra arguments: ${Strings.join(extra, " ")}');
	}

	Map<String, SourceFile> sourceFiles = <String, SourceFile>{};
	int dartBytesRead = 0;

	Future<String> provider(Uri uri) {
	if (uri.scheme != 'file') {
	throw new ArgumentError(uri);
	}
	String source;
	try {
	source = readAll(uriPathToNative(uri.path));
	} on FileIOException catch (ex) {
	throw 'Error: Cannot read "${relativize(cwd, uri, isWindows)}" '
	'(${ex.osError}).';
	}
	dartBytesRead += source.length;
	sourceFiles[uri.toString()] =
	new SourceFile(relativize(cwd, uri, isWindows), source);
	return new Future.immediate(source);
	}

	void info(var message, [api.Diagnostic kind = api.Diagnostic.VERBOSE_INFO]) {
	if (!verbose && identical(kind, api.Diagnostic.VERBOSE_INFO)) return;
	if (enableColors) {
	print('${colors.green("info:")} $message');
	} else {
	print('info: $message');
	}
	}

	bool isAborting = false;

	final int FATAL = api.Diagnostic.CRASH.ordinal \| api.Diagnostic.ERROR.ordinal;
	final int INFO =
	api.Diagnostic.INFO.ordinal \| api.Diagnostic.VERBOSE_INFO.ordinal;

	void handler(Uri uri, int begin, int end, String message,
	api.Diagnostic kind) {
	if (identical(kind.name, 'source map')) {
	// TODO(podivilov): We should find a better way to return source maps from
	// emitter. Using diagnostic handler for that purpose is a temporary hack.
	writeString(sourceMapOut, message);
	return;
	}

	if (isAborting) return;
	isAborting = identical(kind, api.Diagnostic.CRASH);
	bool fatal = (kind.ordinal & FATAL) != 0;
	bool isInfo = (kind.ordinal & INFO) != 0;
	if (isInfo && uri == null && !identical(kind, api.Diagnostic.INFO)) {
	info(message, kind);
	return;
	}
	var color;
	if (!enableColors) {
	color = (x) => x;
	} else if (identical(kind, api.Diagnostic.ERROR)) {
	color = colors.red;
	} else if (identical(kind, api.Diagnostic.WARNING)) {
	color = colors.magenta;
	} else if (identical(kind, api.Diagnostic.LINT)) {
	color = colors.magenta;
	} else if (identical(kind, api.Diagnostic.CRASH)) {
	color = colors.red;
	} else if (identical(kind, api.Diagnostic.INFO)) {
	color = colors.green;
	} else {
	throw 'Unknown kind: $kind (${kind.ordinal})';
	}
	if (uri == null) {
	assert(fatal);
	print(color(message));
	} else if (fatal \|\| showWarnings) {
	SourceFile file = sourceFiles[uri.toString()];
	if (file == null) {
	throw '$uri: file is null';
	}
	print(file.getLocationMessage(color(message), begin, end, true, color));
	}
	if (fatal && throwOnError) {
	isAborting = true;
	throw new AbortLeg(message);
	}
	}

	Uri uri = cwd.resolve(arguments[0]);
	if (packageRoot == null) {
	packageRoot = uri.resolve('./packages/');
	}

	info('package root is $packageRoot');

	// TODO(ahe): We expect the future to be complete and call value
	// directly. In effect, we don't support truly asynchronous API.
	String code = api.compile(uri, libraryRoot, packageRoot, provider, handler,
	options).value;
	if (code == null) {
	fail('Error: Compilation failed.');
	}
	String sourceMapFileName =
	sourceMapOut.path.substring(sourceMapOut.path.lastIndexOf('/') + 1);
	code = '$code\n//@ sourceMappingURL=${sourceMapFileName}';
	writeString(out, code);
	int bytesWritten = code.length;
	info('compiled $dartBytesRead bytes Dart -> $bytesWritten bytes '
	'$outputLanguage in ${relativize(cwd, out, isWindows)}');
	if (!explicitOut) {
	String input = uriPathToNative(arguments[0]);
	String output = relativize(cwd, out, isWindows);
	print('Dart file $input compiled to $outputLanguage: $output');
	}
	}

	class AbortLeg {
	final message;
	AbortLeg(this.message);
	toString() => 'Aborted due to --throw-on-error: $message';
	}

	void writeString(Uri uri, String text) {
	if (uri.scheme != 'file') {
	fail('Error: Unhandled scheme ${uri.scheme}.');
	}
	var file = new File(uriPathToNative(uri.path)).openSync(FileMode.WRITE);
	file.writeStringSync(text);
	file.closeSync();
	}

	String readAll(String filename) {
	var file = (new File(filename)).openSync(FileMode.READ);
	var length = file.lengthSync();
	var buffer = new List<int>(length);
	var bytes = file.readListSync(buffer, 0, length);
	file.closeSync();
	return new String.fromCharCodes(new Utf8Decoder(buffer).decodeRest());
	}

	void fail(String message) {
	print(message);
	exit(1);
	}

	void compilerMain(Options options) {
	var root = uriPathToNative("/$LIBRARY_ROOT");
	List<String> argv = ['--library-root=${options.script}$root'];
	argv.addAll(options.arguments);
	compile(argv);
	}

	void help() {
	// This message should be no longer than 20 lines. The default
	// terminal size normally 80x24. Two lines are used for the prompts
	// before and after running the compiler. Another two lines may be
	// used to print an error message.
	print('''
	Usage: dart2js [options] dartfile

	Compiles Dart to JavaScript.

	Common options:
	-o<file> Generate the output into <file>.
	-c Insert runtime type checks and enable assertions (checked mode).
	-h Display this message (add -v for information about all options).''');
	}

	void verboseHelp() {
	print('''
	Usage: dart2js [options] dartfile

	Compiles Dart to JavaScript.

	Supported options:
	-o<file>, --out=<file>
	Generate the output into <file>.

	-c, --enable-checked-mode, --checked
	Insert runtime type checks and enable assertions (checked mode).

	-h, /h, /?, --help
	Display this message (add -v for information about all options).

	-v, --verbose
	Display verbose information.

	-p<path>, --package-root=<path>
	Where to find packages, that is, "package:..." imports.

	--minify
	Generate minified output.

	--suppress-warnings
	Do not display any warnings.

	--enable-diagnostic-colors
	Add colors to diagnostic messages.

	The following options are only used for compiler development and may
	be removed in a future version:

	--output-type=dart
	Output Dart code instead of JavaScript.

	--throw-on-error
	Throw an exception if a compile-time error is detected.

	--library-root=<directory>
	Where to find the Dart platform libraries.

	--allow-mock-compilation
	Do not generate a call to main if either of the following
	libraries are used: dart:dom, dart:html dart:io.

	--enable-concrete-type-inference
	Enable experimental concrete type inference.

	--disallow-unsafe-eval
	Disables dynamic generation of code in the generated output. This is
	necessary to satisfy CSP restrictions (see http://www.w3.org/TR/CSP/).
	This flag is not continuously tested. Please report breakages and we
	will fix them as soon as possible.''');
	}

	void helpAndExit(bool verbose) {
	if (verbose) {
	verboseHelp();
	} else {
	help();
	}
	exit(0);
	}

	void helpAndFail(String message) {
	help();
	print('');
	fail(message);
	}

	void main() {
	try {
	compilerMain(new Options());
	} catch (exception, trace) {
	try {
	print('Internal error: $exception');
	} catch (ignored) {
	print('Internal error: error while printing exception');
	}
	try {
	print(trace);
	} finally {
	exit(253); // 253 is recognized as a crash by our test scripts.
	}
	}
	}