blob: 8a5081b175274e1fd8d611393af1b14c282fe1aa [file] [log] [blame]
// Copyright (c) 2015, 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 dart_style.src.rule.type_argument;
import '../chunk.dart';
import 'rule.dart';
/// Rule for splitting a list of type arguments or type parameters. Type
/// parameters split a little differently from normal value argument lists. In
/// particular, this tries harder to avoid splitting before the first type
/// argument since that looks stranger with `<...>` than it does with `(...)`.
/// The values for a rule for `n` arguments are:
/// * `0`: No splits at all.
/// * `1 ... n`: Split before one argument, starting from the last.
/// * `n + 1`: Split before all arguments.
/// If there is only one type argument, the last two cases collapse and there
/// are only two values.
class TypeArgumentRule extends Rule {
/// The chunks prior to each positional type argument.
final List<Chunk> _arguments = [];
int get cost => Cost.typeArgument;
int get numValues => _arguments.length == 1 ? 2 : _arguments.length + 2;
/// Remembers [chunk] as containing the split that occurs right before a type
/// argument in the list.
void beforeArgument(Chunk chunk) {
bool isSplit(int value, Chunk chunk) {
// Don't split at all.
if (value == Rule.unsplit) return false;
// Split before every argument.
if (value == numValues - 1) return true;
// Split before a single argument. Try later arguments before earlier ones
// to try to keep as much on the first line as possible.
return chunk == _arguments[_arguments.length - value];
String toString() => 'TypeArg${super.toString()}';