how to parse page content in a template with tags

Hi,

I have to write several pages composing a catalogue and describing products. For easy of maintenance, my idea is to write a template that can parse the page content, extract predefined components and build the output page.

Assuming an example page like:

article: …
weight: …
image: …

what is the suggested way to parse the page content from the template and generate the final page which presentation details are encoded in the template?

do I have to use/define new/ tags?

Thanks, Sergio