Please not TCL. It is intrinsicly inefficient and, to my eyes, quite
inelegant.
(My preference is Scheme, but I somehow suspect that this isn't
necessarily going to be popular with People who have been brought
up on shell programming and C.)
Whatever, the language, the important issues are a secure/safe
abstract machine in which it is to execute.
On viewers, I suspect execution efficency isn't particularly important
when talking about display generation or forms. But once the door is
opened a little, some folk are going to want to do more general
computations.
If we talk about execution on the servers or in caches, then I think
we need to be concerned about efficiency.
The larger issue when one starts talking about pushing executable
candy-grams around the network is controlling those that have more
than an extremely short life span.
--karl--