Initial API for the Dart front_end package.

pkg/front_end/lib/compilation_error.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.
+
+/// Defines the API for the front end to communicate information about
+/// compilation errors to clients.
+library front_end.compilation_error;
+
+import 'package:source_span/source_span.dart' show FileSpan;
+
+/// A single error that occurred during compilation, and information about where
+/// it occurred.
+///
+/// TODO(paulberry): add a reference to the analyzer error code.
+///
+/// TODO(paulberry): add a correction message, once most analyzer errors have
+/// one.
+abstract class CompilationError {
+  /// A text description of the compile error.
+  String get message;
+
+  /// The source location where the error occurred.
+  FileSpan get location;

[Siggi Cherem (dart-lang), 2016/10/17 16:27:29]

consider switching to just use the interface (SourceSpan) for the API
declaration?

Most of the time we'll likely use FileSpan, but I can imagine cases where we
might want to report an error with information derived from summaries or other
kernel files. In those cases, we might need a different implementation of
SourceSpan.

[Paul Berry, 2016/10/17 17:04:27]

Done.

+}