Use FastaMessage instead of String. Part 1.

pkg/front_end/lib/src/fasta/compiler_command_line.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.
 
 library fasta.compiler_command_line;
 
 import 'dart:io' show exit;
 
 import 'command_line.dart' show CommandLine, deprecated_argumentError;
 
 import 'compiler_context.dart' show CompilerContext;
 
 import 'package:kernel/target/targets.dart'
     show Target, getTarget, TargetFlags, targets;
 
+import 'fasta_codes.dart'
+    show FastaMessage, codeFastaUsageLong, codeFastaUsageShort, codeUnspecified;
+
 const Map<String, dynamic> optionSpecification = const <String, dynamic>{
   "--compile-sdk": Uri,
   "--fatal": ",",
   "--output": Uri,
   "-o": Uri,
   "--packages": Uri,
   "--platform": Uri,
   "--sdk": Uri,
   "--target": String,
   "-t": String,
@@ skipping 95 matching lines @@
       dynamic f(CompilerContext context)) {
     return CompilerContext.withGlobalOptions(
         new CompilerCommandLine(programName, arguments), f);
   }
 
   static CompilerCommandLine forRootContext() {
     return new CompilerCommandLine("", [""]);
   }
 }
 
-String computeUsage(String programName, bool verbose) {
+FastaMessage computeUsage(String programName, bool verbose) {
   String basicUsage = "Usage: $programName [options] dartfile\n";
   String summary;
-  String options = (verbose ? allOptions : frequentOptions).trim();
+  String options =
+      (verbose ? codeFastaUsageLong.template : codeFastaUsageShort.template)
+          .trim();
   switch (programName) {
     case "outline":
       summary =
           "Creates an outline of a Dart program in the Dill/Kernel IR format.";
       break;
 
     case "compile":
       summary = "Compiles a Dart program to the Dill/Kernel IR format.";
       break;
 
@@ skipping 11 matching lines @@
       basicUsage = "Usage: $programName [options] patched_sdk fullOutput "
           "outlineOutput\n";
   }
   StringBuffer sb = new StringBuffer(basicUsage);
   if (summary != null) {
     sb.writeln();
     sb.writeln(summary);
     sb.writeln();
   }
   sb.write(options);
-  return "$sb";
+  // TODO(ahe): Don't use [codeUnspecified].
+  return codeUnspecified.bind("$sb")(null, -1);
 }
-
-const String frequentOptions = """
-Frequently used options:
-
-  -o <file> Generate the output into <file>.
-  -h        Display this message (add -v for information about all options).
-""";
-
-const String allOptions = """
-Supported options:
-
-  -o <file>, --output=<file>
-    Generate the output into <file>.
-
-  -h, /h, /?, --help
-    Display this message (add -v for information about all options).
-
-  -v, --verbose
-    Display verbose information.
-
-  --
-    Stop option parsing, the rest of the command line is assumed to be
-    file names or arguments to the Dart program.
-
-  --packages=<file>
-    Use package resolution configuration <file>, which should contain a mapping
-    of package names to paths.
-
-  --platform=<file>
-    Read the SDK platform from <file>, which should be in Dill/Kernel IR format
-    and contain the Dart SDK.
-
-  --target=none|vm|vmcc|vmreify|flutter
-    Specify the target configuration.
-
-  --verify
-    Check that the generated output is free of various problems. This is mostly
-    useful for developers of this compiler or Kernel transformations.
-
-  --dump-ir
-    Print compiled libraries in Kernel source notation.
-
-  --exclude-source
-    Do not include source code in the dill file.
-
-  --compile-sdk=<patched_sdk>
-    Compile the SDK from scratch instead of reading it from 'platform.dill'.
-
-  --sdk=<patched_sdk>
-    Location of the SDK sources for use when compiling additional platform
-    libraries.
-
-  --fatal=errors
-  --fatal=warnings
-  --fatal=nits
-    Makes messages of the given kinds fatal, that is, immediately stop the
-    compiler with a non-zero exit-code. In --verbose mode, also display an
-    internal stack trace from the compiler. Multiple kinds can be separated by
-    commas, for example, --fatal=errors,warnings.
-""";