class Proc def ===(*args) call(*args) end def yield(*args) call(*args) end def to_proc self end def curry(arity=self.arity) type = :proc abs = lambda {|a| a < 0 ? -a - 1 : a} arity = abs[arity] if lambda? type = :lambda self_arity = self.arity if (self_arity >= 0 && arity != self_arity) || (self_arity < 0 && abs[self_arity] > arity) raise ArgumentError, "wrong number of arguments (#{arity} for #{abs[self_arity]})" end end pproc = self make_curry = proc do |given_args=[]| __send__(type) do |*args| new_args = given_args + args if new_args.size >= arity pproc[*new_args] else make_curry[new_args] end end end make_curry.call end def <<(other) ->(*args, &block) { call(other.call(*args, &block)) } end def >>(other) ->(*args, &block) { other.call(call(*args, &block)) } end end