[Templates] Performance cost of 'namespaces'

[Clinton Gormley]

One of the issues that I am finding in my templates as they become more
complex, is the problem of namespace collision, ie just remembering what
variables I have used where, and whether using this variable name is
going to cause problems at a distance.

I use PROCESS rather than INCLUDE to process other blocks, because "I
have read" that there is a significant performance cost to localising
all the variables.

How bad is this?

The alternative would be to use my own namespaces in naming variables,
as in : main.title.xyz

How does this perform in comparison?

I've tended to avoid that, assuming that anything that has to access the
stash (I'm using the XS stash) is going to have an impact as it has to
decide at each level is this a hash, or an array, or a scalar, or a
method etc

How do other people manage this?

thanks

Clint