Bulletin Board Code (BBC)

text2bbc.php

<?php

function text2bbc($text)
{
    $find    = array(
        '~\[b\](.*?)\[/b\]~s',
        '~\[i\](.*?)\[/i\]~s',
        '~\[u\](.*?)\[/u\]~s',
        '~\[size=(.*?)\](.*?)\[/size\]~s',
        '~\[color=(.*?)\](.*?)\[/color\]~s'
    );
    $replace = array(
        '<b>$1</b>',
        '<i>$1</i>',
        '<span style="text-decoration:underline;">$1</span>',
        '<span style="font-size:$1px;">$2</span>',
        '<span style="color:$1;">$2</span>'
    );
    return preg_replace($find, $replace, $text);
}

echo text2bbc('this is some [b]bold text[/b] and this is [color=#FF0000]Red text[/color]');
echo '<br>';
echo text2bbc('this text is [i]italic[/i] and this is not');
echo '<br>';
echo text2bbc('here we have [u]underlined[/u] text');
echo '<br>';
echo text2bbc('this is [size=24]24px[/size] font');