module RuboCop::NodePattern::Macros

Helpers for defining methods based on a pattern string

Public Instance Methods

def_node_matcher(method_name, pattern_str) click to toggle source

Define a method which applies a pattern to an AST node

The new method will return nil if the node does not match If the node matches, and a block is provided, the new method will yield to the block (passing any captures as block arguments). If the node matches, and no block is provided, the new method will return the captures, or `true` if there were none.

# File lib/rubocop/node_pattern.rb, line 422
def def_node_matcher(method_name, pattern_str)
  compiler = RuboCop::NodePattern::Compiler.new(pattern_str, 'node')
  src = "def #{method_name}(node"                "#{compiler.emit_trailing_params});"                "#{compiler.emit_method_code};end"

  file, lineno = *caller.first.split(':')
  class_eval(src, file, lineno.to_i)
end
node_search_body(method_name, trailing_params, prelude, match_code, on_match) click to toggle source
# File lib/rubocop/node_pattern.rb, line 457
def node_search_body(method_name, trailing_params, prelude, match_code,
                     on_match)
  <<-END
    def #{method_name}(node0#{trailing_params})
      #{prelude}
      node0.each_node do |node|
        if #{match_code}
          #{on_match}
        end
      end
      nil
    end
  END
end