pkgs/intl_translation/bin/make_examples_const.dart

#!/usr/bin/env dart
// Copyright (c) 2017, 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.

/// Converts the examples parameter for Intl messages to be const.
library;

import 'dart:io';

import 'package:args/args.dart';
import 'package:dart_style/dart_style.dart';
import 'package:intl_translation/src/language_version.dart';
import 'package:intl_translation/src/message_rewriter.dart';
import 'package:intl_translation/src/messages/main_message.dart';

Future<void> main(List<String> args) async {
  var parser = ArgParser();
  var rest = parser.parse(args).rest;
  if (rest.isEmpty) {
    print('Accepts Dart file paths and rewrites the examples to be const '
        'in Intl.message calls.');
    print('Usage: make_examples_const [options] [file.dart]...');
    print(parser.usage);
    exit(0);
  }

  for (var inputFile in rest) {
    var outputFile = inputFile;
    var file = File(inputFile);
    var content = file.readAsStringSync();
    var newSource = rewriteMessages(content, '$file');
    if (content == newSource) {
      print('No changes to $outputFile');
    } else {
      print('Writing new source to $outputFile');
      var out = File(outputFile);

      var languageVersion = (await findPackageLanguageVersion(file)) ??
          DartFormatter.latestLanguageVersion;
      var formatter = DartFormatter(languageVersion: languageVersion);

      out.writeAsStringSync(formatter.format(newSource));
    }
  }
}

/// Rewrite all Intl.message/plural/etc. calls in [source] which have
/// examples, making them be const.
///
/// Return the modified source code. If there are errors parsing, list
/// [sourceName] in the error message.
String rewriteMessages(String source, String sourceName) {
  var messages = findMessages(source, sourceName);
  messages
      .sort((a, b) => a.sourcePosition?.compareTo(b.sourcePosition ?? 0) ?? 0);
  int? start = 0;
  var newSource = StringBuffer();
  for (var message in messages) {
    if (message.examples.isNotEmpty) {
      newSource.write(source.substring(start!, message.sourcePosition));
      rewrite(newSource, source, message);
      start = message.endPosition;
    }
  }
  newSource.write(source.substring(start!));
  return newSource.toString();
}

void rewrite(StringBuffer newSource, String source, MainMessage message) {
  var sourcePosition = message.sourcePosition;
  if (sourcePosition != null) {
    var originalSource = source.substring(sourcePosition, message.endPosition);
    var examples = nonConstExamples.firstMatch(originalSource);
    if (examples == null) {
      newSource.write(originalSource);
    } else {
      var modifiedSource = originalSource.replaceFirst(
          examples.group(1)!, '${examples.group(1)}const');
      newSource.write(modifiedSource);
    }
  }
}

final RegExp nonConstExamples = RegExp('([\\n,]\\s+examples: ){');