How do forums like this format source code?

johncook

I posted a similar thread on this a few days ago and have been beating my head on this issue since then but have made some little progress. I'm trying to do a simple thing - mimic forums like this that display formatted source code. I indicate source code by using tags:

[ code ] ... [ /code ]

I tried a little test on how to format it using this example:

$textstring = "Here is some code:
[ code ]
<?php
echo 'stuff';
?>
[ /code ]
And here's more:
[ code ]
<?php
echo 'more stuff';
?>
[ /code ]
And that wraps it up!";

// I replace the line breaks otherwise the preg_replace doesn't seem to work
$textstring = str_replace("\n","<br>",$textstring);

// preg replace should put anything between [ code ][ /code ] in a HTML table
echo preg_replace("/\[code\](.*)\[\/code\]/", "<table class='code'><tr><td>"."$1"."</td></tr></table>", $textstring);

If you run the code, you'll see even though there are two instances of my code tags, it just starts at the first code tag, skips over the ones in the middle, ending at the closing code tag at the end to find one pattern match. Is there a way to configure my regex so it identifies each individual piece of source code? Or if I'm completely on the wrong track in tackling this issue, any pointers in the right direction would be appreciated :-)

mrhappiness

try /[code](.*)[/code]/U

johncook

Very cool, thanx! I've done a basic tutorial on regex so wasn't aware of using U at the end (will have to look into how that works).

The other problem is I want to display the PHP code formatted but using highlight_string seems to have no effect inside a preg_replace function. Eg:

echo preg_replace("/[code](.*)[\/code]/U", "<table class='code'><tr><td>".highlight_string("$1",TRUE)."</td></tr></table>", $textstring);

mrhappiness

you perhaps want to have a look at http://de.php.net/manual/en/pcre.pattern.modifiers.php first

you will for sure need the "e" modifier or you do it like this

$highlighted = '<table class="code"><tr><td>'.
highlight_string(
  preg_replace("/(\\[code\\])(.*)(\\[\\/code\\])/siU",
    "$2", 
    $textstring),
  true);

johncook

Sound of angel choirs singing *

It turns out using the e pattern modifier is what got it going - I finally got the result I was after using this code:

$newstring = preg_replace("/[code](.*)[\/code]/sieU", "'<table class=code><tr><td>'.highlight_string('$1',TRUE).'</td></tr></table>'", $textstring);

The s, i and U modifiers also helped big time - thanx for that link to the PHP manual (had never visited that particular page before). Mr Happiness, you've brought me much happiness :-)