pipeline and callback are web application terminology, not template terminology

[metaperl]

What I was trying to get at when I chose the terms callback and pipeline was the difference in how web requests are typically processed.

Yes, what you wrote was a system architect's document. And you also wrote the document in the context of processing web requests. This is definitely fair game for an article on a mod_perl website, but in my eyes, pipeline and callback apply more accurately to web application systems.

CGI::Application is pure pipeline... and regardless of what templating system you choose (even the ones you label callback), it will be used in the manner that you describe for pipeline systems.

Now on the other hand, HTML::Embperl and HTML::Mason (the system, not the template language) are pure callback systems.

Templating could be discussed without bring the web into it and then we could truly see how the execution model of template systems varies... hmm, sounds like a new node to me.

[metaperl]

For example, in this section you say:

The pipeline style does all the work up front in a standard CGI or mod_perl handler, then decides which template to run and passes some data to it. The template has no control flow logic in it, just presentation logic, e.g. show this graphic if this item is on sale.

now, by 'control flow logic' you certainly mean application control flow. because tt (a pipeline system) certainly has control flow constructs within it. but you will never see tt controllling application flow.