lib/src/constants.dart

// 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.

/// The in-progress "tall" formatting style is enabled by passing an experiment
/// flag with this name.
///
/// Note that this isn't a real Dart SDK experiment: Only the formatter supports
/// it. We use the [experimentFlags] API to pass this in so that support for it
/// can be removed in a later version without it being a breaking change to the
/// dart_style library API.
const tallStyleExperimentFlag = 'tall-style';

/// Constants for the cost heuristics used to determine which set of splits is
/// most desirable.
class Cost {
  /// The cost of splitting after the `=>` in a lambda or arrow-bodied member.
  ///
  /// We make this zero because there is already a span around the entire body
  /// and we generally do prefer splitting after the `=>` over other places.
  static const arrow = 0;

  /// The default cost.
  ///
  /// This isn't zero because we want to ensure all splitting has *some* cost,
  /// otherwise, the formatter won't try to keep things on one line at all.
  /// Most splits and spans use this. Greater costs tend to come from a greater
  /// number of nested spans.
  static const normal = 1;

  /// Splitting after a "=".
  static const assign = 1;

  /// Splitting after a "=" when the right-hand side is a collection or cascade.
  static const assignBlock = 2;

  /// Splitting before the first argument when it happens to be a function
  /// expression with a block body.
  static const firstBlockArgument = 2;

  /// The series of positional arguments.
  static const positionalArguments = 2;

  /// Splitting inside the brackets of a list with only one element.
  static const singleElementList = 2;

  /// Splitting the internals of block arguments.
  ///
  /// Used to prefer splitting at the argument boundary over splitting the block
  /// contents.
  static const splitBlocks = 2;

  /// Splitting on the "." in a named constructor.
  static const constructorName = 4;

  /// Splitting a `[...]` index operator.
  static const index = 4;

  /// Splitting before a type argument or type parameter.
  static const typeArgument = 4;

  /// Split between a formal parameter name and its type.
  static const parameterType = 4;
}

/// Constants for the number of spaces for various kinds of indentation.
class Indent {
  /// Reset back to no indentation.
  static const none = 0;

  /// The number of spaces in a block or collection body.
  static const block = 2;

  /// How much wrapped cascade sections indent.
  static const cascade = 2;

  /// The number of spaces in a single level of expression nesting.
  static const expression = 4;

  /// The ":" on a wrapped constructor initialization list.
  static const constructorInitializer = 4;
}