compose

[Jp Calderone]

On Mon, May 05, 2003 at 04:56:32AM +0000, xam wrote:
> i've been truing to get this 'simple' code to work,
> def compose(*funcs):
> ...  if len(funcs)>1:
> ...    return lambda x:funcs[0](compose(funcs[1:])(x))
> ...  else:  return lambda x:funcs[0](x)
> >>> compose(add_5, mul_3, sub_2)(2)
> Traceback (most recent call last):
>   File "<interactive input>", line 1, in ?
>   File "<interactive input>", line 3, in <lambda>
>   File "<interactive input>", line 4, in <lambda>
> TypeError: 'tuple' object is not callable
> does anyone want to give it a shot?
> 

    compose(add_5, mul_3, sub_2) ->

    lambda x: add_5(compose((mul_3, sub_2))(x) ->

    lambda x: (mul_3, sub_2)(x)

  You're missing the extra, magic *:

    return lambda x: funcs[0](compose(*funcs[1:])(x))

  Jp

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