Class: RuboCop::Cop::Style::ComparableClamp

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector, TargetRubyVersion
Includes:
Alignment
Defined in:
lib/rubocop/cop/style/comparable_clamp.rb

Overview

Enforces the use of ‘Comparable#clamp` instead of comparison by minimum and maximum.

This cop supports autocorrection for ‘if/elsif/else` bad style only. Because `ArgumentError` occurs if the minimum and maximum of `clamp` arguments are reversed. When these are variables, it is not possible to determine which is the minimum and maximum:

source,ruby

[1, [2, 3].max].min # => 1 1.clamp(3, 1) # => min argument must be smaller than max argument (ArgumentError)

Examples:


# bad
[[x, low].max, high].min

# bad
if x < low
  low
elsif high < x
  high
else
  x
end

# good
x.clamp(low, high)

Constant Summary collapse

MSG = 
'Use `%<prefer>s` instead of `if/elsif/else`.'
MSG_MIN_MAX = 
'Use `Comparable#clamp` instead.'
RESTRICT_ON_SEND = 
%i[min max].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods included from TargetRubyVersion

maximum_target_ruby_version, minimum_target_ruby_version, required_maximum_ruby_version, required_minimum_ruby_version, support_target_ruby_version?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#array_min_max?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 61

def_node_matcher :array_min_max?, <<~PATTERN
  {
    (send
      (array
        (send (array _ _) :max) _) :min)
    (send
      (array
        _ (send (array _ _) :max)) :min)
    (send
      (array
        (send (array _ _) :min) _) :max)
    (send
      (array
        _ (send (array _ _) :min)) :max)
  }
PATTERN

#if_elsif_else_condition?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 47

def_node_matcher :if_elsif_else_condition?, <<~PATTERN
  {
    (if (send _x :< _min) _min (if (send _max :< _x) _max _x))
    (if (send _min :> _x) _min (if (send _max :< _x) _max _x))
    (if (send _x :< _min) _min (if (send _x :> _max) _max _x))
    (if (send _min :> _x) _min (if (send _x :> _max) _max _x))
    (if (send _max :< _x) _max (if (send _x :< _min) _min _x))
    (if (send _x :> _max) _max (if (send _x :< _min) _min _x))
    (if (send _max :< _x) _max (if (send _min :> _x) _min _x))
    (if (send _x :> _max) _max (if (send _min :> _x) _min _x))
  }
PATTERN

#on_if(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 78

def on_if(node)
  return unless if_elsif_else_condition?(node)

  if_body, elsif_body, else_body = *node.branches

  else_body_source = else_body.source

  if min_condition?(node.condition, else_body_source)
    min = if_body.source
    max = elsif_body.source
  else
    min = elsif_body.source
    max = if_body.source
  end

  prefer = "#{else_body_source}.clamp(#{min}, #{max})"

  add_offense(node, message: format(MSG, prefer: prefer)) do |corrector|
    autocorrect(corrector, node, prefer)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 100

def on_send(node)
  return unless array_min_max?(node)

  add_offense(node, message: MSG_MIN_MAX)
end