Class: RuboCop::Cop::Style::SymbolProc

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/style/symbol_proc.rb

Overview

Use symbols as procs when possible.

Examples:

# bad
something.map { |s| s.upcase }

# good
something.map(&:upcase)

Constant Summary collapse

MSG = 
'Pass `&:%s` as an argument to `%s` instead of a block.'
PROC_NODE = 
s(:send, s(:const, nil, :Proc), :new)

Constants included from Util

Util::ASGN_NODES, Util::EQUALS_ASGN_NODES, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, cop_type, #correct, #debug?, #display_cop_names?, #display_style_guide?, #excluded_file?, inherited, #initialize, #join_force?, lint?, match?, #message, non_rails, qualified_cop_name, rails?, #reference_url, #relevant_file?, #style_guide_url

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, command?, comment_line?, const_name, directions, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, move_pos, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, within_node?

Methods included from PathUtil

hidden?, issue_deprecation_warning, match_path?, relative_path

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 44

def autocorrect(node)
  lambda do |corrector|
    block_send_or_super, _block_args, block_body = *node
    _receiver, method_name, _args = *block_body

    if super?(block_send_or_super)
      args = *block_send_or_super
      autocorrect_method(corrector, node, args, method_name)
    else
      _breceiver, _bmethod_name, *args = *block_send_or_super
      autocorrect_method(corrector, node, args, method_name)
    end
  end
end

#autocorrect_method(corrector, node, args, method_name) ⇒ Object 



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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 59

def autocorrect_method(corrector, node, args, method_name)
  if args.empty?
    autocorrect_no_args(corrector, node, method_name)
  else
    autocorrect_with_args(corrector, node, args, method_name)
  end
end

#autocorrect_no_args(corrector, node, method_name) ⇒ Object 



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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 67

def autocorrect_no_args(corrector, node, method_name)
  corrector.replace(block_range_with_space(node), "(&:#{method_name})")
end

#autocorrect_with_args(corrector, node, args, method_name) ⇒ Object 



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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 71

def autocorrect_with_args(corrector, node, args, method_name)
  corrector.insert_after(args.last.loc.expression, ", &:#{method_name}")
  corrector.remove(block_range_with_space(node))
end

#begin_pos_for_replacement(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 84

def begin_pos_for_replacement(node)
  block_send_or_super, _block_args, _block_body = *node
  expr = block_send_or_super.loc.expression

  if (paren_pos = (expr.source =~ /\(\s*\)$/))
    expr.begin_pos + paren_pos
  else
    node.loc.begin.begin_pos
  end
end

#block_range_with_space(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 76

def block_range_with_space(node)
  block_range =
    Parser::Source::Range.new(node.loc.expression.source_buffer,
                              begin_pos_for_replacement(node),
                              node.loc.end.end_pos)
  range_with_surrounding_space(block_range, :left)
end

#can_shorten?(block_args, block_body) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 103

def can_shorten?(block_args, block_body)
  # something { |x, y| ... }
  return false unless block_args.children.size == 1
  return false unless block_body && block_body.type == :send

  receiver, _method_name, args = *block_body

  # method in block must be invoked on a lvar without args
  return false if args
  return false unless receiver && receiver.type == :lvar

  block_arg_name, = *block_args.children.first
  receiver_name, = *receiver

  block_arg_name == receiver_name
end

#ignored_method?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 99

def ignored_method?(name)
  ignored_methods.include?(name.to_s)
end

#ignored_methods ⇒ Object 



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

def ignored_methods
  cop_config['IgnoredMethods']
end

#on_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 19

def on_block(node)
  block_send_or_super, block_args, block_body = *node

  if super?(block_send_or_super)
    bmethod_name = :super
  else
    _breceiver, bmethod_name, _bargs = *block_send_or_super
  end

  # TODO: Rails-specific handling that we should probably make
  # configurable - https://github.com/bbatsov/rubocop/issues/1485
  # we should ignore lambdas & procs
  return if block_send_or_super == PROC_NODE
  return if [:lambda, :proc].include?(bmethod_name)
  return if ignored_method?(bmethod_name)
  return unless can_shorten?(block_args, block_body)

  _receiver, method_name, _args = *block_body
  add_offense(node,
              :expression,
              format(MSG,
                     method_name,
                     bmethod_name))
end

#super?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/symbol_proc.rb', line 120

def super?(node)
  [:super, :zsuper].include?(node.type)
end