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Message-ID: <4D7E60BA.4040208@yahoo.com.au>
Date: Tue, 15 Mar 2011 05:38:50 +1100
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To: Martin Scotta <martinscotta@gmail.com>
CC: PHP internals <internals@lists.php.net>
References: <AANLkTimXFUA6egG99Z-0F24TqSFDrDuhVD7Nu=0C2mdW@mail.gmail.com>
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Subject: Re: [PHP-DEV] preg_replace does not replace all occurrences
From: mail_ben_schmidt@yahoo.com.au (Ben Schmidt)

On 15/03/11 2:18 AM, Martin Scotta wrote:
> I chose the simplest example to show the preg_replace behavior,

You've GOT to be kidding. The SIMPLEST?!

How about an example that doesn't require escaping ALL the interesting
characters involved?

Here's a modified version that I think it quite a bit simpler:

<?php
function test($str) {
    static $re = '/(^|[^a])b/';
    static $change = '$1ab';

    echo $str, PHP_EOL; // input
    echo preg_replace($re, $change, $str), PHP_EOL, PHP_EOL; // output
}

test("str bb str"); // bug?
test("str abab str"); // ok
test("b str b"); // ok
test("ab str ab"); // ok
?>

The way I interpret it, it should put an 'a' before every 'b' that is
not already preceded by an 'a'.

But the buggy case gives 'str abb str' rather than the expected
'str abab str'.

It does look like a bug to me.

Ben.



> there are
> better (and safer) ways to scape slash characters.
> Anyways, *is this the expected preg_replace behavior?*
>
>   Martin
>
> <?php
> function test($str) {
>      static $re = '/(^|[^\\\\])\'/';
>      static $change = '$1\\\'';
>
>      echo $str, PHP_EOL,
>          preg_replace($re, $change, $str), PHP_EOL, PHP_EOL;
> }
>
> test("str '' str"); // bug?
> test("str \\'\\' str"); // ok
> test("'str'"); // ok
> test("\'str\'"); // ok
>
> ----
> Expected:
>
> str '' str
> str \'\' str
>
> str \'\' str
> str \'\' str
>
> 'str'
> \'str\'
>
> \'str\'
> \'str\'
>
> ----
> Result:
>
> str '' str
> str \'' str
>
> str \'\' str
> str \'\' str
>
> 'str'
> \'str\'
>
> \'str\'
> \'str\'
>
>
>   Martin Scotta
>