Le 30/03/2012 14:52, Steven Schveighoffer a écrit :
On Fri, 30 Mar 2012 08:22:12 -0400, deadalnix <[email protected]> wrote:
Le 30/03/2012 14:13, Steven Schveighoffer a écrit :
On Fri, 30 Mar 2012 08:10:14 -0400, deadalnix <[email protected]>
wrote:
I would expect this not to work, because bar isn't defined in module1
and template are supposed to use declaration scope, not instantiation
scope (unless it is mixin template).
Right, I think it's the way it works now. But consider that the template
instantiation *does* pull in some stuff from the instantiation scope
(i.e. the template's module may not import the type being used to
instantiate). I think it would be OK for the compiler to consider UFCS
functions from the type's defining module as well, since you cannot
instantiate the template for that particular type without having
imported that module (i.e. it's guaranteed to instantiate the same no
matter what module does it first).
-Steve
It does pull information from it's own scope and what is passed as
parameter. So it would still fail for the UFCS case.
I don't see a clean solution for that, because of ambiguities. That
something that is not new and not specific to UFCS.
Why would there be ambiguities? Unlike C include files, D modules are
consistently compiled, unaffected by importing other modules. In order
to instantiate a template templ!Foo, either the module that defines
templ, or the module who is instantiating *must* import the module that
defines Foo. Knowing this, the compiler should be able to deduce that it
can consistently compile tmpl!Foo even if it pulls in UFCS functions
from Foo's module or modules that Foo's module imports.
Immagine you want to define your own to!xxx() for your type xxx. (It
is dumb case because you have toString, but an interesting exercise
because for your own stuff, not something that is specified in the
language - like toString - the same could happen with no easy solution.
I don't think this disproves anything. It should be possible without
ambiguity given the rules I stated.
-Steve
You are messing up everything.
First, this have NOTHING to do with UFCS. Second, current D import
system have no ambiguity. But you propose to change that system. That
would introduce ambiguity.
Even if you don't believe me, which is fine, it is safe to assume so
unless you can prove otherwise.
