正则表达式php，匹配字符串与变量文本（字母，数字，下划线，[]）

Question

I am building a simple template engine (in PHP) and I need regex for my loop code, the loop should look something like this:

{loop var=menu[0]}
<li><a href="{link}">{text}</a></li>
{/loop}

where "menu[0]" can be any string of uppercase or lowercase letters with/without underscores, numbers and box parentheses ([])

the '{loop var=', '}' and '{/loop}' always stay the same

I'll be using php's preg_match to make the comparison.

my regex so far (which is probably wildly off) is:

/[{loop var=][\w\s_0-9\[\]][}]/

my php is something like this:

function loop($template) {
    preg_match($pattern, $template, $matches);
    foreach ($matches as $key => $match) {
        ...
        $var = str_replace(array('{loop var=', '}'), '', $match));
        $data = $this->get($var);
        ...
        $loop_code = str_replace('{' . $var . '}', $data, $loop_code);
        ...
    }
}

the input is my template above, the desired output is below

<ul>
<li><a href="<?php print $menu[0][0]['link']; ?>"><?php print $menu[0][0]['text']; ?></a></li>
<li><a href="<?php print $menu[0][1]['link']; ?>"><?php print $menu[0][1]['text']; ?></a></li>
</ul>

to do this I need preg_match to match any of these strings (in their entirity)

{loop var=menu[0]}

{loop var=menu_main}

{loop var=__menu}

{loop var=MenuMain}

Thank you for any input.

Answer 1

I'm not sure if this is exactly what you're after but the following regular expression will match any of the 4 examples you have provided after the = and before the closing }

$replacement = '/(menu\[\d]|(m|M)enu(_)?(m|M)ain|__menu))/';

I'm just not too sure how you want to use it and what you are going to replace it with.

If you also want to capture the {loop var=xxxxx } You'll need this:

$replacement = '//({loop var=(menu\[\d]|(m|M)enu(_)?(m|M)ain|__menu)})/';

Answer 2

You're misusing square brackets, which indicate only a single character . Try using a resource such as http://regex101.com/ to test things out.

Rather than mucking with str_replace to clean things up afterward, just use the full power of preg_match() :

$template = "{loop var=menu[0]}\n<li><a href=\"{link}\">{text}</a></li>\n{/loop}";
$pattern  = "/\{loop var=([\w\[\]]+)\}(.*?)\{\/loop\}/ism";
preg_match($pattern, $template, $matches);
$var_name = $matches[1];
$template_code = $matches[2];