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Date: Thu, 01 Apr 2021 13:21:14 +0100
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To: internals@lists.php.net,Arnold Daniels <arnold.adaniels.nl@gmail.com>
Message-ID: <7A382E20-5CB5-4802-BAB0-49AECF32C4F2@gmail.com>
Subject: Re: [PHP-DEV] Why is assert limited to a debugging feature only?
From: rowan.collins@gmail.com (Rowan Tommins)

Hi,

On 1 April 2021 09:24:54 BST, Arnold Daniels <arnold=2Eadaniels=2Enl@gmail=
=2Ecom> wrote:
>The documentation of `assert`
>([https://php=2Enet/assert)](https://www=2Ephp=2Enet/manual/en/function=
=2Eassert=2Ephp))
>states that's debugging only=2E This is further enforced by php=2Eini fla=
gs
>to disable assertions in production=2E

This is, in a sense, looking at things the wrong way around: the main feat=
ure of the built-in assert() statement is that it can be disabled in produc=
tion, and the assertion code will not run at all=2E That feature is useful =
if you want to write assertions that run in development but have zero perfo=
rmance cost in production=2E

If you leave them switched on permanently, the advantage of using the buil=
t-in assert() over writing your own becomes very small - the definition wou=
ld be two simple lines of code=2E There's nothing to stop you doing that, t=
hough; the documentation is just giving advice=2E

The two libraries you linked to concentrate on a very different feature: c=
oncisely writing certain common conditions, such as type and range checks=
=2E It might seem reasonable to include common features like this in the la=
nguage, but the fact that you linked two different libraries demonstrates w=
hy that might not be a good idea: the API and feature set are hard to get r=
ight=2E Once a feature is added to the language it is very difficult to cha=
nge=2E

Regards,

--=20
Rowan Tommins
[IMSoP]