Dear list members,
> Incidentally, it is of course possible for a function to invoke impure
> functions while still being pure itself (ie, it ensures the impurity
> does not "leak out").  One question to those more familiar with current
> language research: any recommended resources out there about this topic?
>
> Cheers,
> Dario Teixeira
>
>
>   
You can easily infer purity (meaning no affectation) of an ocaml 
expression using the same algorithm
than for exception (numerous papers on that subkect) ... just tag ":=" 
and "<-" as being able to raise the fake exception "#Affect" which
can not be catch by any try (because its name starts with a "#") ...

Cheers,
Christophe