From: Fabrice Le Fessant <fabrice@lefessant.net>
To: Edgar Friendly <thelema314@gmail.com>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] is there a more concise way to write this?
Date: Fri, 20 Jan 2012 14:50:21 +0100 [thread overview]
Message-ID: <CAHvkLrO41_jh8UkKK2gcXk0M10Saa54J49An2eib=591TX83yA@mail.gmail.com> (raw)
In-Reply-To: <4F196C25.7070402@gmail.com>
On Fri, Jan 20, 2012 at 2:29 PM, Edgar Friendly <thelema314@gmail.com> wrote:
>> it potentially eliminates a lot of linear comparisons to
>> find the correct match case (I don't think that the compiler would be
>> able to optimise that to a hash-based or index-based lookup)
>
>
> Isn't the compiler's compilation strategy for match cases able to build an
> optimized tree of comparisons in cases like this? I agree there's no easy
> index or hash strategy for this, but I'd expect it to turn this pattern
> matching into the equivalent of:
>
> if a then if b then [a;b] else [a]
> else if b then [b] else []
Indeed, the four line pattern-matching is turned into two consecutive
tests. In many cases, the pattern-matching compiler only generates the
optimal number of tests, so never be scared of creating big complex
patterns...
Regards,
Fabrice
next prev parent reply other threads:[~2012-01-20 13:50 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-20 6:38 Martin DeMello
2012-01-20 6:46 ` Valentin ROBERT
2012-01-20 6:58 ` Martin DeMello
2012-01-20 8:37 ` David Allsopp
2012-01-20 13:29 ` Edgar Friendly
2012-01-20 13:50 ` Fabrice Le Fessant [this message]
2012-01-20 13:58 ` oliver
2012-01-20 14:05 ` Edgar Friendly
2012-01-20 14:12 ` David Allsopp
2012-01-20 14:23 ` Fabrice Le Fessant
2012-01-20 14:23 ` Edgar Friendly
2012-01-20 8:37 ` Sebastien Ferre
2012-01-20 9:11 ` Jerome Vouillon
2012-01-20 9:34 ` Fabrice Le Fessant
2012-01-20 10:27 ` Arnaud Spiwack
2012-01-20 8:52 ` Lin
2012-01-20 9:08 ` Valentin ROBERT
2012-01-20 9:19 ` Lin
2012-01-20 10:21 ` Martin DeMello
2012-01-20 9:38 ` oliver
2012-01-20 13:59 ` Edgar Friendly
2012-01-20 14:42 ` oliver
2012-01-20 15:31 ` Fabrice Le Fessant
2012-01-20 21:04 ` oliver
2012-01-20 21:09 ` oliver
2012-01-20 20:40 ` oliver
2012-01-20 21:07 ` Martin DeMello
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