Class: RuboCop::Cop::Style::Lambda

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, `::RuboCop::Cop::AutoCorrector`, `::RuboCop::Cop::Base`, `::RuboCop::ExcludeLimit`, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain: self, `::RuboCop::Cop::ConfigurableEnforcedStyle`, `::RuboCop::Cop::Base`, `::RuboCop::Cop::AutocorrectLogic`, `::RuboCop::Cop::IgnoredNode`, `::RuboCop::Util`, RuboCop::AST::Sexp
Inherits:	RuboCop::Cop::Base Object RuboCop::Cop::Base RuboCop::Cop::Style::Lambda
Defined in:	lib/rubocop/cop/style/lambda.rb

Overview

(by default) checks for uses of the lambda literal syntax for single line lambdas, and the method call syntax for multiline lambdas. It is configurable to enforce one of the styles for both single line and multiline lambdas as well.

Examples:

EnforcedStyle: line_count_dependent (default)

# bad
f = lambda { |x| x }
f = ->(x) do
      x
    end

# good
f = ->(x) { x }
f = lambda do |x|
      x
    end

EnforcedStyle: lambda

# bad
f = ->(x) { x }
f = ->(x) do
      x
    end

# good
f = lambda { |x| x }
f = lambda do |x|
      x
    end

EnforcedStyle: literal

# bad
f = lambda { |x| x }
f = lambda do |x|
      x
    end

# good
f = ->(x) { x }
f = ->(x) do
      x
    end

Constant Summary

LITERAL_MESSAGE =
# File 'lib/rubocop/cop/style/lambda.rb', line 53

'Use the `-> { ... }` lambda literal syntax for %<modifier>s lambdas.'

METHOD_MESSAGE =
# File 'lib/rubocop/cop/style/lambda.rb', line 54
```
'Use the `lambda` method for %<modifier>s lambdas.'
```

OFFENDING_SELECTORS =
# File 'lib/rubocop/cop/style/lambda.rb', line 56

{
  style: {
    lambda: { single_line: '->', multiline: '->' },
    literal: { single_line: 'lambda', multiline: 'lambda' },
    line_count_dependent: { single_line: 'lambda', multiline: '->' }
  }
}.freeze

`::RuboCop::Cop::Base` - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

`::RuboCop::Cop::ConfigurableEnforcedStyle` - Included

SYMBOL_TO_STRING_CACHE

Class Attribute Summary

`::RuboCop::Cop::AutoCorrector` - Extended

support_autocorrect?

`::RuboCop::Cop::Base` - Inherited

.gem_requirements, .lint?,
.support_autocorrect?	Returns if class supports autocorrect.
.support_multiple_source?	Override if your cop should be called repeatedly for multiple investigations Between calls to `on_new_investigation` and `on_investigation_end`, the result of `processed_source` will remain constant.

Class Method Summary

`::RuboCop::Cop::Base` - Inherited

.autocorrect_incompatible_with	List of cops that should not try to autocorrect at the same time as this cop.
.badge	Naming.
.callbacks_needed, .cop_name, .department,
.documentation_url	Returns a url to view this cops documentation online.
.exclude_from_registry	Call for abstract Cop classes.
.inherited,
.joining_forces	Override and return the Force class(es) you need to join.
.match?	Returns true if the cop name or the cop namespace matches any of the given names.
.new,
.requires_gem	Register a version requirement for the given gem name.
.restrict_on_send

`::RuboCop::ExcludeLimit` - Extended

exclude_limit	Sets up a configuration option to have an exclude limit tracked.
transform

Instance Attribute Summary

Instance Method Summary

#on_block(node) (also: #on_numblock)
#on_numblock(node)

Alias for #on_block.
#arguments_with_whitespace(node) private
#autocorrect_method_to_literal(corrector, node) private
#lambda_arg_string(args) private
#message(node, selector) private
#message_line_modifier(node) private
#offending_selector?(node, selector) ⇒ Boolean private

`::RuboCop::Cop::ConfigurableEnforcedStyle` - Included

#alternative_style, #alternative_styles, #ambiguous_style_detected,
#conflicting_styles_detected	Alias for ConfigurableEnforcedStyle#no_acceptable_style!.
#correct_style_detected, #no_acceptable_style!, #opposite_style_detected, #style, #style_detected, #style_parameter_name, #supported_styles, #unexpected_style_detected,
#unrecognized_style_detected	Alias for ConfigurableEnforcedStyle#no_acceptable_style!.

`::RuboCop::Cop::Base` - Inherited

#add_global_offense	Adds an offense that has no particular location.
#add_offense	Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.
#begin_investigation	Called before any investigation.
#callbacks_needed,
#cop_config	Configuration Helpers.
#cop_name, #excluded_file?,
#external_dependency_checksum	This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:
#inspect,
#message	Gets called if no message is specified when calling `add_offense` or `add_global_offense` Cops are discouraged to override this; instead pass your message directly.
#name	Alias for Base#cop_name.
#offenses,
#on_investigation_end	Called after all on_…
#on_new_investigation	Called before all on_…
#on_other_file	Called instead of all on_…
#parse	There should be very limited reasons for a Cop to do it’s own parsing.
#parser_engine,
#ready	Called between investigations.
#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument	Reserved for Cop::Cop.
#complete_investigation	Called to complete an investigation.
#correct, #current_corrector,
#current_offense_locations	Reserved for Commissioner:
#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation	Actually private methods.
#use_corrector

`::RuboCop::Cop::AutocorrectLogic` - Included

#disable_offense, #disable_offense_at_end_of_line, #disable_offense_before_and_after, #disable_offense_with_eol_or_surround_comment, #max_line_length,
#range_by_lines	Expand the given range to include all of any lines it covers.
#range_of_first_line, #range_overlaps_offense?, #string_continuation, #string_continuation?, #surrounding_heredoc, #surrounding_percent_array

`::RuboCop::Cop::IgnoredNode` - Included

#ignore_node, #ignored_node?, #part_of_ignored_node?, #ignored_nodes

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#arguments_with_whitespace(node) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 115


def arguments_with_whitespace(node)
  node.loc.begin.end.join(node.arguments.loc.end)
end

#autocorrect_method_to_literal(corrector, node) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 104


def autocorrect_method_to_literal(corrector, node)
  corrector.replace(node.send_node, '->')

  return unless node.arguments?

  arg_str = "(#{lambda_arg_string(node.arguments)})"

  corrector.insert_after(node.send_node, arg_str)
  corrector.remove(arguments_with_whitespace(node))
end

#lambda_arg_string(args) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 119


def lambda_arg_string(args)
  args.children.map(&:source).join(', ')
end

#message(node, selector) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 89


def message(node, selector)
  message = selector == '->' ? METHOD_MESSAGE : LITERAL_MESSAGE

  format(message, modifier: message_line_modifier(node))
end

#message_line_modifier(node) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 95


def message_line_modifier(node)
  case style
  when :line_count_dependent
    node.multiline? ? 'multiline' : 'single line'
  else
    'all'
  end
end

#offending_selector?(node, selector) ⇒ `Boolean` (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 83


def offending_selector?(node, selector)
  lines = node.multiline? ? :multiline : :single_line

  selector == OFFENDING_SELECTORS[:style][style][lines]
end

#on_block(node) Also known as: #on_numblock

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 64


def on_block(node)
  return unless node.lambda?

  selector = node.send_node.source

  return unless offending_selector?(node, selector)

  add_offense(node.send_node, message: message(node, selector)) do |corrector|
    if node.send_node.lambda_literal?
      LambdaLiteralToMethodCorrector.new(node).call(corrector)
    else
      autocorrect_method_to_literal(corrector, node)
    end
  end
end

#on_numblock(node)

Alias for #on_block.

[ GitHub ]

# File 'lib/rubocop/cop/style/lambda.rb', line 79


alias on_numblock on_block

Class: RuboCop::Cop::Style::Lambda

Overview

Constant Summary

::RuboCop::Cop::Base - Inherited

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

Class Method Summary

::RuboCop::Cop::Base - Inherited

::RuboCop::ExcludeLimit - Extended

Instance Attribute Summary

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

::RuboCop::Cop::Base - Inherited

::RuboCop::Cop::AutocorrectLogic - Included

Instance Method Summary

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

::RuboCop::Cop::Base - Inherited

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

Instance Method Details

#arguments_with_whitespace(node) (private)

#autocorrect_method_to_literal(corrector, node) (private)

#lambda_arg_string(args) (private)

#message(node, selector) (private)

#message_line_modifier(node) (private)

#offending_selector?(node, selector) ⇒ Boolean (private)

#on_block(node) Also known as: #on_numblock

#on_numblock(node)

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::ConfigurableEnforcedStyle` - Included

`::RuboCop::Cop::AutoCorrector` - Extended

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::ExcludeLimit` - Extended

`::RuboCop::Cop::ConfigurableEnforcedStyle` - Included

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::AutocorrectLogic` - Included

`::RuboCop::Cop::ConfigurableEnforcedStyle` - Included

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::AutocorrectLogic` - Included

`::RuboCop::Cop::IgnoredNode` - Included

#offending_selector?(node, selector) ⇒ `Boolean` (private)