module Hamster::List
def find_index
def find_index return nil unless block_given? i = 0 list = self loop do return nil if list.empty? return i if yield(list.head) i += 1 list = list.tail end end
def find_index return nil unless block_given? i = 0 list = self loop do return nil if list.empty? return i if yield(list.head) i += 1 list = list.tail end end