Create a package that implements a JSON-RPC 2.0 server.

pkg/json_rpc_2/lib/src/utils.dart

Index: pkg/json_rpc_2/lib/src/utils.dart
diff --git a/pkg/json_rpc_2/lib/src/utils.dart b/pkg/json_rpc_2/lib/src/utils.dart
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+// Copyright (c) 2014, 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 json_rpc_2.utils;
+
+import 'dart:async';
+
+import 'package:stack_trace/stack_trace.dart';
+
+typedef ZeroArgumentFunction();
+
+/// Like [new Future.sync], but automatically wraps the future in a
+/// [Chain.track] call.
+Future syncFuture(callback()) => Chain.track(new Future.sync(callback));
+
+/// Returns a sentence fragment listing the elements of [iter].
+///
+/// This converts each element of [iter] to a string and separates them with
+/// commas and/or "and" where appropriate.
+String toSentence(Iterable iter) {
+  if (iter.length == 1) return iter.first.toString();
+  return iter.take(iter.length - 1).join(", ") + " and ${iter.last}";
+}
+
+/// Returns [name] if [number] is 1, or the plural of [name] otherwise.
+///
+/// By default, this just adds "s" to the end of [name] to get the plural. If
+/// [plural] is passed, that's used instead.
+String pluralize(String name, int number, {String plural}) {
+  if (number == 1) return name;
+  if (plural != null) return plural;
+  return '${name}s';
+}
+
+/// A regular expression to match the exception prefix that some exceptions'
+/// [Object.toString] values contain.
+final _exceptionPrefix = new RegExp(r'^([A-Z][a-zA-Z]*)?(Exception|Error): ');
+
+/// Get a string description of an exception.
+///
+/// Many exceptions include the exception class name at the beginning of their
+/// [toString], so we remove that if it exists.
+String getErrorMessage(error) =>
+    error.toString().replaceFirst(_exceptionPrefix, '');