I just got it! (invariant/const)
lionello at lunesu.remove.com
Wed Apr 9 19:30:49 PDT 2008
"Jason House" <jason.james.house at gmail.com> wrote in message
news:ftislk$3m0$1 at digitalmars.com...
> Janice Caron Wrote:
>> On 09/04/2008, Georg Wrede <georg at nospam.org> wrote:
>> > This is even stronger than (1) above, it is clearer,
>> > and it's *right*.
>> Sure, but you don't need to outlaw code that does nothing. :-)
> D already outlaws having code that isn't run. I would prefer for code
> that does nothing to be considered an error. Of course, with most
> functions being impure, that's tough to enforce. With pure functions, it
> should be easy.
Why? If pure-ness (uh, purity?) can be checked, it can also be deducted (*),
so the compiler could optimize/complain in either case.
Tagging a function explicitely as "pure" would only enable a constraint as
to what other functions can be called, which is something I'd rather see
solved using more generalized tagging abilities (See Scott Meyers'
presentation on red-code, green-code ).
Maybe identifiers between the parameter list and the function body could
work as ad-hoc constraints. This would work for pure and nothrow, and the
user can add whatever identifier/constraint s/he wants.
(*) Is this conclusion correct? It feels correct, but I don't think I can
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