higher order functions
higher order functions

kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground