Class: RuboCop::Cop::Style::NestedModifier

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

Overview

This cop checks for nested use of if, unless, while and until in their modifier form.

Examples:


# bad
something if a if b

# good
something if b && a

Constant Summary collapse

MSG = 
'Avoid using nested modifiers.'.freeze

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, 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 IfNode

#elsif?, #if_else?, #if_node_parts, #modifier_if?, #ternary?

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

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?, #details, #display_cop_names?, #display_style_guide?, #duplicate_location?, #excluded_file?, #extra_details?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #reference_url, #relevant_file?, #style_guide_url, #target_ruby_version

Methods included from Sexp

#s

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_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

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 56

def autocorrect(node)
  return unless node.if_type?

  ancestor = node.ancestors.first
  return unless ancestor.if_type?

  autocorrect_if_unless(ancestor, node)
end

#autocorrect_if_unless(outer_node, inner_node) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 65

def autocorrect_if_unless(outer_node, inner_node)
  outer_cond, = *outer_node

  range = range_between(inner_node.loc.keyword.begin_pos,
                        outer_cond.source_range.end_pos)

  lambda do |corrector|
    corrector.replace(range, new_expression(outer_node, inner_node))
  end
end

#check(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 33

def check(node)
  return if part_of_ignored_node?(node)
  return unless modifier?(node)

  ancestor = node.ancestors.first
  return unless ancestor &&
                [:if, :while, :until].include?(ancestor.type) &&
                modifier?(ancestor)

  add_offense(node, :keyword)
  ignore_node(node)
end

#left_hand_operand(node, operator) ⇒ Object 



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

def left_hand_operand(node, operator)
  cond, = *node

  expr = cond.source
  expr = "(#{expr})" if cond.or_type? && operator == '&&'.freeze
  expr
end

#modifier?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 46

def modifier?(node)
  modifier_if?(node) || modifier_while_or_until?(node)
end

#modifier_while_or_until?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 50

def modifier_while_or_until?(node)
  node.loc.respond_to?(:keyword) &&
    %w(while until).include?(node.loc.keyword.source) &&
    node.modifier_form?
end

#new_expression(outer_node, inner_node) ⇒ Object 



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

def new_expression(outer_node, inner_node)
  outer_keyword = outer_node.loc.keyword.source
  operator = replacement_operator(outer_keyword)
  lh_operand = left_hand_operand(outer_node, operator)
  rh_operand = right_hand_operand(inner_node, outer_keyword)

  "#{outer_keyword} #{lh_operand} #{operator} #{rh_operand}"
end

#on_if(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 29

def on_if(node)
  check(node)
end

#on_until(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 25

def on_until(node)
  check(node)
end

#on_while(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 21

def on_while(node)
  check(node)
end

#replacement_operator(keyword) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 85

def replacement_operator(keyword)
  keyword == 'if'.freeze ? '&&'.freeze : '||'.freeze
end

#requires_parens?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 107

def requires_parens?(node)
  node.or_type? ||
    !(RuboCop::Node::COMPARISON_OPERATORS & node.children).empty?
end

#right_hand_operand(node, left_hand_keyword) ⇒ Object 



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# File 'lib/rubocop/cop/style/nested_modifier.rb', line 97

def right_hand_operand(node, left_hand_keyword)
  cond, = *node
  keyword = node.loc.keyword.source

  expr = cond.source
  expr = "(#{expr})" if requires_parens?(cond)
  expr = "!#{expr}" unless left_hand_keyword == keyword
  expr
end