class RuboCop::Cop::Style::SymbolProc

Use symbols as procs when possible.

@example

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

# good
something.map(&:upcase)

Constants

MSG
PROC_NODE

Public Instance Methods

autocorrect(node) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 50
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
    else
      _breceiver, _bmethod_name, *args = *block_send_or_super
    end
    autocorrect_method(corrector, node, args, method_name)
  end
end
autocorrect_method(corrector, node, args, method_name) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 64
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) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 72
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) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 76
def autocorrect_with_args(corrector, node, args, method_name)
  arg_range = args.last.source_range
  arg_range = range_with_surrounding_comma(arg_range, :right)
  replacement = " &:#{method_name}"
  replacement = ',' + replacement unless arg_range.source.end_with?(',')
  corrector.insert_after(arg_range, replacement)
  corrector.remove(block_range_with_space(node))
end
begin_pos_for_replacement(node) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 93
def begin_pos_for_replacement(node)
  block_send_or_super, _block_args, _block_body = *node
  expr = block_send_or_super.source_range

  if (paren_pos = (expr.source =~ /\(\s*\)$/))
    expr.begin_pos + paren_pos
  else
    node.loc.begin.begin_pos
  end
end
block_range_with_space(node) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 85
def block_range_with_space(node)
  block_range =
    Parser::Source::Range.new(node.source_range.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) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 112
def can_shorten?(block_args, block_body)
  # something { |x, y| ... }
  return false unless block_args.children.size == 1
  return false if non_shortenable_args?(block_args)
  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) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 108
def ignored_method?(name)
  ignored_methods.include?(name.to_s)
end
ignored_methods() click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 104
def ignored_methods
  cop_config['IgnoredMethods']
end
non_shortenable_args?(block_args) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 134
def non_shortenable_args?(block_args)
  # something { |&x| ... }
  # something { |*x| ... }
  [:blockarg, :restarg].include?(block_args.children.first.type)
end
on_block(node) click to toggle source
# 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

  sb = node.source_range.source_buffer
  block_start = node.loc.begin.begin_pos
  block_end = node.loc.end.end_pos
  range = Parser::Source::Range.new(sb, block_start, block_end)

  add_offense(node,
              range,
              format(MSG,
                     method_name,
                     bmethod_name))
end
super?(node) click to toggle source
# File lib/rubocop/cop/style/symbol_proc.rb, line 130
def super?(node)
  [:super, :zsuper].include?(node.type)
end