Method: Fast.expression_from

Defined in:
lib/fast.rb

.expression_from(node) ⇒ String

Extracts a node pattern expression from a given node supressing identifiers and primitive types. Useful to index abstract patterns or similar code structure.

Examples:

Fast.expression_from(Fast.ast('1')) # => '(int _)'
Fast.expression_from(Fast.ast('a = 1')) # => '(lvasgn _ (int _))'
Fast.expression_from(Fast.ast('def name; person.name end')) # => '(def _ (args) (send (send nil _) _))'

Parameters:

Returns:

  • (String) —

    with an pattern to search from it.

See Also:



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# File 'lib/fast.rb', line 342

def expression_from(node)
  case node
  when Parser::AST::Node
    children_expression = node.children.map(&method(:expression_from)).join(' ')
    "(#{node.type}#{" #{children_expression}" if node.children.any?})"
  when nil, 'nil'
    'nil'
  when Symbol, String, Numeric
    '_'
  end
end