class Crispr::Mutations::Arithmetic

Mutates arithmetic operations such as +, -, *, /, etc.

def mutations_for(node)

Returns:
  • (Array) - mutated nodes

Parameters:
  • node (Parser::AST::Node) -- the AST node to inspect 
def mutations_for(node)
  return [] unless node.is_a?(Parser::AST::Node)
  return [] unless node.type == :send
  receiver, method_name, *args = node.children
  return [] unless args.size == 1
  return [] unless (COMMUTATIVE.keys + NON_COMMUTATIVE.keys).include?(method_name)
  replacements = COMMUTATIVE[method_name] || NON_COMMUTATIVE[method_name]
  mutations = replacements.map do |op|
    Parser::AST::Node.new(:send, [receiver, op, args.first])
  end
  # Additional mutations
  mutations << receiver
  mutations << args.first
  # For commutative operators, swap operands
  mutations << Parser::AST::Node.new(:send, [args.first, method_name, receiver]) if COMMUTATIVE.key?(method_name)
  mutations
end