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Date: Mon, 29 Sep 2014 16:02:11 +0200
From: Pierre Chambart <pierre.chambart@laposte.net>
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To: Goswin von Brederlow <goswin-v-b@web.de>, caml-list@inria.fr
References: <CAEQMQo=bZnk2+GRD1RpW_W-2GVrugVPgMCguwAYSYj7dqY3A_g@mail.gmail.com> <CAN=ouMSbJNEWeJ=1XG1nqRSS=c3WMFvHMQF+jDOh9rDyz62dJQ@mail.gmail.com> <20140929120817.GB20628@frosties>
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Subject: Re: [Caml-list] Why List.map does not be implemented
 tail-recursively?

On 29/09/2014 14:08, Goswin von Brederlow wrote:
> And I'll will do the same, reply anyway.
>
> You can't write List.map tail recursive unless:
>
> 1) You use List.rev (List.rev_map fn list).
>
> or
>
> 2) Use hacks to create a mutable list so you can grow it head to tail
> instead of tail to head.
>
> The fastest code seems to be when you do List.map recursively up to
> some limit (say 1000 items) and return the remainder. Repeat and glue
> the lists together into one large list using hacks.
>
> MfG
> 	Mrvn
>
Please, don't do that hack ! The compiler assumes immutable data are not
mutated and optimise knowing that.
-- 
Pierre