Hello, I'm not sure if the correct term is "parser" but what I want to do is to create a pseudo-language using PHP for HTML-based pages. For example:

<?php

function calendar() {
print "hello world";
}

?>

<html... blah blah...

Below is the calendar
:calendar:

</body>
</html>

I'm building a site for my Dad's business and he doesn't know any programming. So I need to provide him with simple code like :calendar: for him to simply punch in. All he's going to do is sign into the web-based admin interface. If he wants to change some text/design/add new page/etc., all he'll have to do is click, type, and voila. However, the admin script will change the original file. None of his changes will be saved into a database.

Could someone suggest some methods of approach, please? I'm not well-skilled in programming or all the technical terms but I'm willing to learn. If someone could help, I would appreciate some explanations/suggestions on how to do this using the approach above. If in your opinion, using a database is easier/better then I will get one. Thanks for any help!