class Opal::Rewriters::ForRewriter

def assign_loop_variable(loop_variable, tmp_loop_variable)
  case loop_variable.type
  when :mlhs # multiple left-hand statement like in "for i,j in [[1, 2], [3, 4]]"
    loop_variable.updated(:masgn, [loop_variable, tmp_loop_variable])
  else # single argument like "for i in (0..3)"
    loop_variable << tmp_loop_variable
  end
end