Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:99450
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain mindplay.dk from 209.85.192.176 cause and error)
MIME-Version: 1.0
In-Reply-To: <CAF+90c-9Fci5XMYWwB6meryg+mUb=vxiwo+EjN7X1iGHXNPi1g@mail.gmail.com>
References: <CADqTB_gFoRB1pFS6L6s9OfsWAtnGbMTDz-nNV-+ysX-x5H=NRg@mail.gmail.com>
 <CAF+90c-9Fci5XMYWwB6meryg+mUb=vxiwo+EjN7X1iGHXNPi1g@mail.gmail.com>
Date: Thu, 8 Jun 2017 09:10:33 +0200
Message-ID: <CADqTB_h5Cib1v4vnkvPM+mdmTSQd0dOneGXqaLaGqOMU6z8qcA@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="94eb2c1b592e76d2e305516d8ca6"
Subject: Re: [PHP-DEV] preg_match() option for anchored offset?
From: rasmus@mindplay.dk (Rasmus Schultz)

--94eb2c1b592e76d2e305516d8ca6
Content-Type: text/plain; charset="UTF-8"

> You are looking for the \G anchor or the A modifier.

Both of these options work great!

I've submitted a patch to the manual page with a note explaining these
options.

Thanks :-)


On Wed, Jun 7, 2017 at 10:13 PM, Nikita Popov <nikita.ppv@gmail.com> wrote:

> On Wed, Jun 7, 2017 at 10:03 PM, Rasmus Schultz <rasmus@mindplay.dk>
> wrote:
>
>> What do you think about adding another option to preg_match() to allow the
>> $offset parameter to be treated as the start anchor?
>>
>> The manual proposes to do this:
>>
>>     $subject = "abcdef";
>>     $pattern = '/^def/';
>>     $offset = 3;
>>     preg_match($pattern, substr($subject, $offset), $matches);
>>
>> In other words, use substr() to copy the entire remainder of the string.
>>
>> I just wrote a simple SQL parser tonight, and had to use this approach,
>> which (I imagine) must be pretty inefficient?
>>
>> I'd like to be able to do the following:
>>
>>     $subject = "abcdef";
>>     $pattern = '/^def/';
>>     $offset = 3;
>>     preg_match($pattern, $subject, $matches, PREG_ANCHOR_OFFSET, $offset);
>>
>> This new option would make the ^ anchor work from the given $offset, which
>> allows me to parse the entire $subject without copying anything.
>>
>> Thoughts?
>>
>
> You are looking for the \G anchor or the A modifier.
>
> Nikita
>
>

--94eb2c1b592e76d2e305516d8ca6--