Question

Edit: Maybe I should make this part clear. A user is writing the template. So I want the syntax to be simple, and I can’t trust them with powerful template engines.

So, I need a template engine that will be used to write emails, using tokens (easy) with conditional logic (less easy).

Example: Hello{if first_name} dear {first_name}{endif}, blah blah blah.

If first_name is not available, it should read: Hello, blah blah blah.

I was able to get it working using eval… but we all know eval is evil.

$body = preg_replace('/{if ([^{\|}]+)}/i', '<?php if(isset(\$tokens[\'$1\'])):?>', $body);
$body = preg_replace('/{endif}/i', '<?php endif;?>', $body);

Can anyone point me towards a tutorial on this one? I can’t seem to find anything beyond simple token replacement.

Answer 1

Using the comments from everyone, I was able to figure out how to quickly make my own secure template engine with custom syntax.

Let’s say I want to make {first_name|buddy} be the first_name variable if it’s set, but if it’s not set use the string “buddy” as default.

Use a powerful template engine, like Smarty. Smarty has support for this, but I don’t like the syntax {$first_name|default:"buddy"}

Replace all occurrences of your custom syntax with the correct syntax

preg_replace('/{([\w\s]+)\|([\w\s]+)}/', '{\$$1|default:"$2"}', $content);

Then just run it through Smarty. This is essentially the same as using eval, but secure. Thanks guys.