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Class: RuboCop::AST::NodePattern

Overview

This class performs a pattern-matching operation on an AST node.

Detailed syntax: /docs/modules/ROOT/pages/node_pattern.adoc

Initialize a new NodePattern with NodePattern.new(pattern_string), then pass an AST node to #match. Alternatively, use one of the class macros in Macros to define your own pattern-matching method.

If the match fails, nil will be returned. If the match succeeds, the return value depends on whether a block was provided to #match, and whether the pattern contained any "captures" (values which are extracted from a matching AST.)

  • With block: #match yields the captures (if any) and passes the return value of the block through.

  • With no block, but one capture: the capture is returned.

  • With no block, but multiple captures: captures are returned as an array.

  • With no block and no captures: #match returns true.

Constant Summary

Class Method Summary

::RuboCop::SimpleForwardable - Extended

def_delegators

Instance Attribute Summary

Instance Method Summary

MethodDefiner - Included

#as_lambda, #compile_as_lambda, #def_node_matcher, #def_node_search, #compile_init, #def_helper, #emit_keyword_list, #emit_lambda_code, #emit_method_code, #emit_node_search, #emit_node_search_body, #emit_param_list, #emit_params, #emit_retval, #emit_yield_capture,
#wrapping_block

This method minimizes the closure for our method.

Constructor Details

.new(str, compiler: Compiler.new) ⇒ NodePattern

[ GitHub ] 

  


# File 'lib/rubocop/ast/node_pattern.rb', line 77



def initialize(str, compiler: Compiler.new)
  @pattern = str
  @ast = compiler.parser.parse(str)
  @compiler = compiler
  @match_code = @compiler.compile_as_node_pattern(@ast, var: VAR)
  @cache = {}
end


  







Class Method Details



  

    .descend(element) {|element| ... } 
  



  

    


Yields its argument and any descendants, depth-first.



  





  
Yields:


    
  
  • 
    (element)
  
    • 





  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 59



def self.descend(element, &block)
  return to_enum(__method__, element) unless block

  yield element

  if element.is_a?(::RuboCop::AST::Node)
    element.children.each do |child|
      descend(child, &block)
    end
  end

  nil
end


  







Instance Attribute Details



  

    #ast   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 73



attr_reader :pattern, :ast, :match_code


  








  

    #match_code   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 73



attr_reader :pattern, :ast, :match_code


  








  

    #pattern   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 73



attr_reader :pattern, :ast, :match_code


  







Instance Method Details



  

    #==(other)  
    Also known as: #eql?
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 90



def ==(other)
  other.is_a?(NodePattern) && other.ast == ast
end


  








  

    #as_json(_options = nil)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 107



def as_json(_options = nil) # :nodoc:
  pattern
end


  








  

    #encode_with(coder)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 111



def encode_with(coder) # :nodoc:
  coder['pattern'] = pattern
end


  








  

    #eql?(other)  
  



  

    


Alias for #==.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 93



alias eql? ==


  








  

    #freeze  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 119



def freeze
  @match_code.freeze
  @compiler.freeze
  super
end


  








  

    #init_with(coder)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 115



def init_with(coder) # :nodoc:
  initialize(coder['pattern'])
end


  








  

    #marshal_dump  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 103



def marshal_dump # :nodoc:
  pattern
end


  








  

    #marshal_load(pattern)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 99



def marshal_load(pattern) # :nodoc:
  initialize pattern
end


  








  

    #match(*args, **rest, &block)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 85



def match(*args, **rest, &block)
  @cache[:lambda] ||= as_lambda
  @cache[:lambda].call(*args, block: block, **rest)
end


  








  

    #to_s  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/ast/node_pattern.rb', line 95



def to_s
  "#<#{self.class} #{pattern}>"
end