Templating webpages is a tricky business with a lot of issues and options, and the vast majority of people do it totally and completely wrong. A template, in terms of documents, is any document fragment with blank spaces designed for you to ‘fill’ in. It is something that establishes a pattern. In terms of web pages, a template is the design and interface aspect of a site, it should be entirely separate from the logical portions of the site.

Let me restate that “it needs to be entirely separate from the logical portions of the site”. The primary reason for this is maintainability. The reason we use templates in the first place is to organize our development and have two distinct layers, the logic and the design. Remixing logic into design (as smarty and others do) is counter to the primary reason we chose to use templates in the first place. With a proper template system if there is a database or looping issue we know where to look right away and we don’t have to sift through the 20 templates that make up a page in order to find which one has the bug.
So, I will introduce the templatling system I wrote that forces this issue. (it will appear below) The first thing we need to do in creating a perfect template system is balance out ease of use, speed, and determine how it will function and where it will store it’s template files. It also will need ‘complete’ separation of logic and design.

A few things:

If I request index.php in the root directory of a site, the template engine will look in TPL_BASEDIR + “/index.php/” (yes, a directory of the name of the file) for the individual parts of that template. We will also have a global directory for headers, footers and the engine will look backwards up to three directories to try and find a template.
Template files will have a .tpl extension and will NOT be eval’d so that no code can be run in them and there will be no temptation for the “quick fix” of adding code to them. There will be one exception to allowing eval’d code and that will be code that is in html styled <php> tags for outputting dates or other small single variables. (this was an addition to help in transition from systems like smarty).

We want to be able to set some scheme defaults for our template, things we don’t want to bother with in the logic portion, mostly these will be color codes for css files and pages. (this helps to keep design out of the programmers hands)
We need to be able to have multiple sites using the same template engine.

We need to be able to sling sql statements and query result sets to the engine and have it use those if possible. This is a very DRY approach, similar to how rails does some things.

It needs to be able to process css and javascript files as well as html fragments.

We want a set of functions that also are design related for doing things inside the templates if we need, things similar to the “cycle()” ruby function which are automatically called, but are set and forget. This is useful when dealing with row colors so the programmer does not need to worry about colors or stye classes.

We want the template system to be fast so we build in a mechanism so that the pre-processed templates are not loaded more than once.

What we end up with is a fast and proven system, see:

The template system( txt )

To use this you would include the file and set up a template name replace.tpl which has the contents of:

“Here is the {MYVARIABLE} for sale”

in PHP you do :

$replacements[’template’] = ‘replace.tpl’;

$replacements[’myvariable’] = “house”;

template($replacements);

and you will get “Here is the house for sale”

If you want, you can also use your templates from javascript as well. I have some big plans and loads of ideas for ways to use JSON and prototype.

A very similar system was in use at my old work (this is an improvement and revamped version I wrote for another job a while back), we managed 20+ programmers of various skill levels with this template engine and it worked perfectly. Sites managing tens of millions of hits per day use this system and it works well.

We also never had to poke around in HTML to look for a programming bug.

Try it, you might like it. You can even easily turn it into a class, if you are running PHP5 turning it into a class will not have any slowing effects as it did in prior versions..
p.s. Later I will post some old code for doing in-memory content caching using shared memory (schmop) it is easily fitted into the above template system to speed it up even more.

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