std.traits and std.string incompatible ?

[Jonathan M Davis]

On Tuesday, March 08, 2011 16:11:09 Jonathan M Davis wrote:
> On Tuesday, March 08, 2011 13:24:44 Nick Sabalausky wrote:
> > "Ali Çehreli" <acehreli at yahoo.com> wrote in message
> > news:il5pge$nrr$1 at digitalmars.com...
> > 
> > > On 03/08/2011 08:24 AM, Wilfried Kirschenmann wrote:
> > > > Hi,
> > > > 
> > > > When running the following file:
> > > > 
> > > > #!../dmd2/linux/bin/rdmd -unittest
> > > > import std.string, std.traits;
> > > > void main(string[] args){
> > > > bool test = isNumeric(args[0]);
> > > > }
> > > > 
> > > > I get the error :
> > > > dmd2/linux/bin/../../src/phobos/std/traits.d(2576): Error: template
> > > > std.traits.isNumeric(T) is not a function template
> > > > 
> > > > Is this a bug or is there something deprecated ?
> > > > 
> > > > Wilfried
> > > 
> > > isNumeric is a template. You are supposed to give it a type:
> > >   if (isNumeric!SomeType)
> > > 
> > > or at compile time:
> > >   static if (isNumeric!SomeType)
> > > 
> > > It doesn't work with string values. Although unnecessary, you could do
> > > 
> > > this:
> > >     bool test = isNumeric!(typeof(args[0]));
> > 
> > No, there's an isNumeric in *both* std.traits and std.string. The one in
> > std.traits is a template that takes a type. But the one in std.string is
> > a function that takes a string and checks if the value of the string is
> > numeric.
> > 
> > I'm on the latest D2 (2.052) and I just tried the example and got the
> > same result. But if I *only* import std.string then it works. So it
> > sounds like a bug: I forget the exact details of the rules involving
> > overloading across modules, but one of two things should happen with the
> > original example:
> > 
> > A. It should know that you meant std.string.isNumeric because of how
> > you're calling it.
> > 
> > or:
> > 
> > B. It should complain that there's an ambiguity between
> > std.string.isNumeric and std.traits.isNumeric and require you to
> > disambiguate with either "std.traits." or "std.string."
> > 
> > I'm not sure which of those it's supposed to do, but it's clearly not
> > doing either, so I'd file it as a bug: http://d.puremagic.com/issues/
> 
> isNumeric in std.string is a function. In std.traits, it's an eponymous
> template. The eponymous template should require the !. There's no function
> to feed the argument to. There shouldn't be any ambiguity of any kind.
> Overload set rules and whatnot should have nothing to do with this. This
> is definitely a bug.

Reported: http://d.puremagic.com/issues/show_bug.cgi?id=5721

- Jonathan M Davis