module RuboCop::NodePattern::Macros
Helpers for defining methods based on a pattern string
Public Instance Methods
def_node_matcher(method_name, pattern_str)
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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
def_node_search(method_name, pattern_str)
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Define a method which recurses over the descendants of an AST node, checking whether any of them match the provided pattern
If the method name ends with '?', the new method will return `true` as soon as it finds a descendant which matches. Otherwise, it will yield all descendants which match.
# File lib/rubocop/node_pattern.rb, line 438 def def_node_search(method_name, pattern_str) compiler = RuboCop::NodePattern::Compiler.new(pattern_str, 'node') if method_name.to_s.end_with?('?') on_match = 'return true' prelude = '' else yieldval = compiler.emit_capture_list yieldval = 'node' if yieldval.empty? on_match = "yield(#{yieldval})" prelude = "return enum_for(:#{method_name}, node0" "#{compiler.emit_trailing_params}) unless block_given?" end src = node_search_body(method_name, compiler.emit_trailing_params, prelude, compiler.match_code, on_match) filename, lineno = *caller.first.split(':') class_eval(src, filename, lineno.to_i) end
node_search_body(method_name, trailing_params, prelude, match_code, on_match)
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# 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