Delayed evaluation of expressions

[Lorenzo Donati <lorenzodonatibz@...>]

Hi All!

This is an attempt to both satisfy a curiosity of mine and
start a discussion on a topic that seems recurring lately and (IIRC) 
pops up from time to time.

More specifically, I happened to notice in various threads that there 
could be a need for a way in Lua to delay the evaluation of expressions.

Lately, in particular, it has been mentioned in the context of error 
management to avoid building a complex error message when the error 
actually doesn't occur.

What I wonder now is whether the possibility of delaying the evaluation 
of an expression would be useful also in other contexts.

If it would, then maybe it is worth considering what should be done to 
add to Lua such a feature (or a more general one that could comprise it) 
and what could be the consequences (pros and cons) and if the feature 
could be general enough to be in "Lua spirit".

Thanks for any contribution.

Cheers.
-- Lorenzo