Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:82470
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain zend.com designates 209.85.220.170 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <54DB0BC0.20304@gmail.com>
References: <CA+9eiLuNjTa8JzBgnZE5iuv5BZ4Kw4Ehk1ivxPUetNSmZ43JMw@mail.gmail.com>
	<CAL=_i_m78Zo5euReKsvFfrLknFq7KEzoNnrrBefC987u+=+yHQ@mail.gmail.com>
	<CA+9eiLuUFiKwOR-BqQEmkQirpAMxgb0GE70Zz7h4WDsd1Me8FQ@mail.gmail.com>
	<CAGa2bXYDvdvRLiOpDk8EnvE00JE4x47SXB9fET4uO2Er_F6s_w@mail.gmail.com>
	<CAL=_i_=mGc_0u0YDCQ7Jiqn_ggyJmQSd_mk_snf7ArDpDXO53A@mail.gmail.com>
	<CA+9eiLur0DVGBNkzFkiTj3POL5B9H0D8=5wE-wuwN2O-FQZNyg@mail.gmail.com>
	<CAL=_i_m=XDKtc2iCSjoquaHkmX862gyMweKS5Xw4AS--oLj19w@mail.gmail.com>
	<CA+9eiLsX=mOOgXmNBKD1L6WKx2=Vy81mThaKa1XCjjAw6R=2vA@mail.gmail.com>
	<CAGa2bXYYp0WQmnTnbsHXzc8XGG0PxOVHu7XvwiMCSJiUWoKeCg@mail.gmail.com>
	<CAGa2bXbKs8cGRTQ1sfeRonnmVXtp7ftVDkz_ALmqr8OnczQxCg@mail.gmail.com>
	<CAGa2bXZ8Wy7bUYgtbajr+GkpQtQEjQLMbFT2mSB5OEnLO2mgfg@mail.gmail.com>
	<CAL=_i_kypYpa3t06peRKwtww=cbh+KhM+iAOtotDGNaFfJBuVA@mail.gmail.com>
	<54DAFD32.3000005@gmail.com>
	<CA+9eiLtswwOqku57nHLu8fmHOwzvVcqkHTehBQOPUqQb5P2BUw@mail.gmail.com>
	<54DB0BC0.20304@gmail.com>
Date: Wed, 11 Feb 2015 15:25:35 +0400
Message-ID: <CA+9eiLsK1JJbyGu5Fxf+MNz63wb8K0661rkMm-h+vTVUZo+0SQ@mail.gmail.com>
To: Stanislav Malyshev <smalyshev@gmail.com>
Cc: Joe Watkins <pthreads@pthreads.org>, Yasuo Ohgaki <yohgaki@ohgaki.net>, 
	=?UTF-8?Q?Fran=C3=A7ois_Laupretre?= <francois@tekwire.net>, 
	PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=089e0115fd0226de90050ece433d
Subject: Re: [PHP-DEV] Design by Contract
From: dmitry@zend.com (Dmitry Stogov)

--089e0115fd0226de90050ece433d
Content-Type: text/plain; charset=UTF-8

On Wed, Feb 11, 2015 at 10:58 AM, Stanislav Malyshev <smalyshev@gmail.com>
wrote:

> Hi!
>
> > 1) contracts in doc-commetns https://wiki.php.net/rfc/dbc
> >
> > /**
> >  * @requires ($a >= 0)
> >  */
> > function foo($a) {
> > }
>
> We've spent several years rejecting annotations because no information
> can be in comments, not even a little bit, not even a tiny. Now we'd
> have full-blown running code in comments? How would this code be
> debugged/profiled/interpreted by tools? Writing PHP parser is not easy
> right now, but this would turn it into nightmare (what if you have a
> comment inside @requires? etc.)
>

I don't see how this can be implemented in PHP core as well.
This approach is for external tools.


>
> > 2) contracts as part of the language https://wiki.php.net/rfc/dbc2
> >
> > function foo($a)
> >     require($a >= 0)
> > {
> > }
>
> This is a step better but still we have the similar issues with
> readability, to which reuse of 'require' is added.
>
> > 3) contracts in annotations
> >
> > <<requires($a >= 0)>>
> > function foo($a) {
> > }
>
> That one actually looks better to me, but: I'm not sure how annotation
> syntax is supposed to support expressions or closures,


keep AST.


> yet more - how it
> is supposed to share the scope with the function. I.e., if you define
> annotation class/method/function/data structure/whatever it is, what it
> is supposed to receive?


We may have AST transformation pass that would convert these annotations
into assert() and insert them into AST of the function.


> Is it some special form of annotation for this
> purpose only (meh)?
>

yes. some special attributes. requires/ensures/invariant


> Oh, and <<>> syntax is *ugly* ;)
>

It's from HHVM. I don't like it as well, please, propose the better one.

Thanks. Dmitry.


>
> --
> Stas Malyshev
> smalyshev@gmail.com
>

--089e0115fd0226de90050ece433d--