Class: RuboCop::Cop::Performance::CaseWhenSplat
- Includes:
- AutocorrectAlignment
- Defined in:
- lib/rubocop/cop/performance/case_when_splat.rb
Overview
Place ‘when` conditions that use splat at the end of the list of `when` branches.
Ruby has to allocate memory for the splat expansion every time that the ‘case` `when` statement is run. Since Ruby does not support fall through inside of `case` `when`, like some other languages do, the order of the `when` branches does not matter. By placing any splat expansions at the end of the list of `when` branches we will reduce the number of times that memory has to be allocated for the expansion.
This is not a guaranteed performance improvement. If the data being processed by the ‘case` condition is normalized in a manner that favors hitting a condition in the splat expansion, it is possible that moving the splat condition to the end will use more memory, and run slightly slower.
Constant Summary collapse
- MSG =
'Place `when` conditions with a splat ' \ 'at the end of the `when` branches.'.freeze
- ARRAY_MSG =
'Do not expand array literals in `when` conditions.'.freeze
- PERCENT_W =
'%w'.freeze
- PERCENT_CAPITAL_W =
'%W'.freeze
- PERCENT_I =
'%i'.freeze
- PERCENT_CAPITAL_I =
'%I'.freeze
Constants included from AutocorrectAlignment
Constants included from Util
Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES
Instance Attribute Summary
Attributes inherited from Cop
#config, #corrections, #offenses, #processed_source
Instance Method Summary collapse
Methods included from AutocorrectAlignment
#check_alignment, #configured_indentation_width, #display_column, #indentation, #offset
Methods inherited from Cop
#add_offense, all, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_ruby_version
Methods included from AST::Sexp
Methods included from NodePattern::Macros
#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first
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, comment_line?, compatible_external_encoding_for?, directions, double_quotes_acceptable?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, hard_to_type?, interpret_string_escapes, line_distance, line_range, move_pos, needs_escaping?, numeric_range_size, on_node, operator?, parentheses?, parenthesized_call?, preceed?, range_between, range_with_surrounding_comma, range_with_surrounding_space, same_line?, source_range, strip_quotes, stripped_source_upto, to_string_literal, to_supported_styles, to_symbol_literal, within_node?
Methods included from PathUtil
absolute?, match_path?, relative_path
Constructor Details
This class inherits a constructor from RuboCop::Cop::Cop
Instance Method Details
#on_case(case_node) ⇒ Object
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# File 'lib/rubocop/cop/performance/case_when_splat.rb', line 64 def on_case(case_node) when_conditions = case_node.when_branches.flat_map(&:conditions) splat_offenses(when_conditions).reverse_each do |condition| range = condition.parent.loc.keyword.join(condition.source_range) variable, = *condition = variable.array_type? ? ARRAY_MSG : MSG add_offense(condition.parent, range, ) end end |