RE: [Caml-list] recursive modules redux, & interface files

["Don Syme" <dsyme@microsoft.com>]

> > Isn't it feasible to annotate elements of signatures with 
> something that
> > indicates that an identifier really is bound to a value, 
> rather than a
> > module??  i.e.
> 
> You probably meant "rather than a result of an arbitrary computation".

Yes, sorry.

> Yes, it can be done this way, and I believe such annotations in
> signatures are necessary for a full treatment of recursion between
> modules (the Holy Grail :-).  However, they also pollute signatures
> with "implementation details".

I'm not sure this "pollution" is really at that bad, is it?  Users
always have the option of _not_ revealing the extra detail, though with
the result
that they can't do cross-module recursion (or at least they don't get a
guarantee
that all the runtime dynamic checks that verify that data is initialized
before use 
succeed).  And OCaml already have "external" in interfaces, which only
gives
added performance, not extra expressive power.  Phase distinction
annotations seem
as least as useful in practice, and a whole lot simpler than the other
techniques
mentioned....  It seems a whole lot better than having users roll their
own "unsafe"
phase distinctions by hacking in "ref" indirections....  And if a
different, better
solution was found later, then, to use my suggested notation, you could
just revert 
"value" to mean the same as "expr".

Cheers,
Don
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