[Zope] METAL macros

[John Poltorak]

I'm having difficulty figuring out how to make METAL macros reusable. 

Is it standard practice to put macros into a common folder where they can 
be used by numerous different websites?

I just can't get a handle on how they are supposed to be used.

According to:-

http://www.zope.org/Documentation/Books/ZopeBook/2_6Edition/AppendixC.stx

Macros provide a way to define a chunk of presentation in one template, 
and share it in others, so that changes to the macro are immediately 
reflected in all of the places that share it. Additionally, macros are 
always fully expanded, even in a template's source text, so that the 
template appears very similar to its final rendering.


This does not really tell me how they should be used. Can someone give me 
an example of real world usage?


-- 
John