class RuboCop::Cop::Style::MethodDefParentheses
Checks for parentheses around the arguments in method definitions. Both instance and class/singleton methods are checked.
Regardless of style, parentheses are necessary for:
-
Endless methods
-
Argument lists containing a ‘forward-arg` (`…`)
-
Argument lists containing an anonymous rest arguments forwarding (‘*`)
-
Argument lists containing an anonymous keyword rest arguments forwarding (‘**`)
-
Argument lists containing an anonymous block forwarding (‘&`)
Removing the parens would be a syntax error here.
@example EnforcedStyle: require_parentheses (default)
# The `require_parentheses` style requires method definitions # to always use parentheses # bad def bar num1, num2 num1 + num2 end def foo descriptive_var_name, another_descriptive_var_name, last_descriptive_var_name do_something end # good def bar(num1, num2) num1 + num2 end def foo(descriptive_var_name, another_descriptive_var_name, last_descriptive_var_name) do_something end
@example EnforcedStyle: require_no_parentheses
# The `require_no_parentheses` style requires method definitions # to never use parentheses # bad def bar(num1, num2) num1 + num2 end def foo(descriptive_var_name, another_descriptive_var_name, last_descriptive_var_name) do_something end # good def bar num1, num2 num1 + num2 end def foo descriptive_var_name, another_descriptive_var_name, last_descriptive_var_name do_something end
@example EnforcedStyle: require_no_parentheses_except_multiline
# The `require_no_parentheses_except_multiline` style prefers no # parentheses when method definition arguments fit on single line, # but prefers parentheses when arguments span multiple lines. # bad def bar(num1, num2) num1 + num2 end def foo descriptive_var_name, another_descriptive_var_name, last_descriptive_var_name do_something end # good def bar num1, num2 num1 + num2 end def foo(descriptive_var_name, another_descriptive_var_name, last_descriptive_var_name) do_something end
Constants
- MSG_MISSING
- MSG_PRESENT
Public Instance Methods
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 105 def on_def(node) return if forced_parentheses?(node) args = node.arguments if require_parentheses?(args) if arguments_without_parentheses?(node) missing_parentheses(node) else correct_style_detected end elsif parentheses?(args) unwanted_parentheses(args) else correct_style_detected end end
Also aliased as: on_defs
Private Instance Methods
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 169 def anonymous_arguments?(node) return true if node.arguments.any? do |arg| arg.type?(:forward_arg, :restarg, :kwrestarg) end return false unless (last_argument = node.last_argument) last_argument.blockarg_type? && last_argument.name.nil? end
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 147 def arguments_without_parentheses?(node) node.arguments? && !parentheses?(node.arguments) end
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 126 def correct_arguments(arg_node, corrector) corrector.replace(arg_node.loc.begin, ' ') corrector.remove(arg_node.loc.end) end
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 131 def forced_parentheses?(node) # Regardless of style, parentheses are necessary for: # 1. Endless methods # 2. Argument lists containing a `forward-arg` (`...`) # 3. Argument lists containing an anonymous rest arguments forwarding (`*`) # 4. Argument lists containing an anonymous keyword rest arguments forwarding (`**`) # 5. Argument lists containing an anonymous block forwarding (`&`) # Removing the parens would be a syntax error here. node.endless? || anonymous_arguments?(node) end
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 151 def missing_parentheses(node) location = node.arguments.source_range add_offense(location, message: MSG_MISSING) do |corrector| add_parentheses(node.arguments, corrector) unexpected_style_detected 'require_no_parentheses' end end
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 142 def require_parentheses?(args) style == :require_parentheses || (style == :require_no_parentheses_except_multiline && args.multiline?) end
Source
# File lib/rubocop/cop/style/method_def_parentheses.rb, line 161 def unwanted_parentheses(args) add_offense(args, message: MSG_PRESENT) do |corrector| # offense is registered on args node when parentheses are unwanted correct_arguments(args, corrector) unexpected_style_detected 'require_parentheses' end end