I don't suppose there's an easy general way to get the paramaters of a templated type just from the type itself? Ie, a way to get around this:

class Foo(char[] str) {}
static assert(Foo!("a").stringof != Foo!("b").stringof)
// ^ fails because it evaluates to "Foo" != "Foo"

I can probably work around it in my current case by sticking str into a const member of Foo and using that together with .stringof, but thought I'd see if there was a better way.

On Sat, Dec 5, 2009 at 5:36 PM, Nick Sabalausky <a@a.a> wrote:
> I don't suppose there's an easy general way to get the paramaters of a templated type just from the type itself? Ie, a way to get around this:
>
> class Foo(char[] str) {}
> static assert(Foo!("a").stringof != Foo!("b").stringof)
> // ^ fails because it evaluates to "Foo" != "Foo"
>
> I can probably work around it in my current case by sticking str into a const member of Foo and using that together with .stringof, but thought I'd see if there was a better way.

That should just be considered a bug I think.  I think what stringof does is not detailed in the spec beyond "provides a string representation".  Clearly just returning the base name of the template is not the most useful representation of a template type.  Stringof clearly needs to have more thought put into it (as has been brought up many times in the past).

--bb

On Sun, 06 Dec 2009 02:36:58 +0100, Nick Sabalausky <a@a.a> wrote:

> I don't suppose there's an easy general way to get the paramaters of a
> templated type just from the type itself? Ie, a way to get around this:
>
> class Foo(char[] str) {}
> static assert(Foo!("a").stringof != Foo!("b").stringof)
> // ^ fails because it evaluates to "Foo" != "Foo"
>
> I can probably work around it in my current case by sticking str into a
> const member of Foo and using that together with .stringof, but thought I'd
> see if there was a better way.

Use more parentheses. ( Foo!( "a" ) ).stringof gives the right result. Of
course, this still seems rather weird.

-- 
Simen

"Simen kjaeraas" <simen.kjaras@gmail.com> wrote in message news:op.u4h55pbcvxi10f@biotronic-pc.home...
> On Sun, 06 Dec 2009 02:36:58 +0100, Nick Sabalausky <a@a.a> wrote:
>
>> I don't suppose there's an easy general way to get the paramaters of a templated type just from the type itself? Ie, a way to get around this:
>>
>> class Foo(char[] str) {}
>> static assert(Foo!("a").stringof != Foo!("b").stringof)
>> // ^ fails because it evaluates to "Foo" != "Foo"
>>
>> I can probably work around it in my current case by sticking str into a
>> const member of Foo and using that together with .stringof, but thought
>> I'd
>> see if there was a better way.
>
> Use more parentheses. ( Foo!( "a" ) ).stringof gives the right result. Of
> course, this still seems rather weird.
>

Not in D1 unfortunately (or at least 1.051):

-----------------------------------
class Foo(char[] str) {}

pragma(msg, `Foo!("a").stringof: ` ~ Foo!("a").stringof);
pragma(msg, `Foo!("b").stringof: ` ~ Foo!("b").stringof);
pragma(msg, `(Foo!("a")).stringof: ` ~ (Foo!("a")).stringof);
pragma(msg, `(Foo!("b")).stringof: ` ~ (Foo!("b")).stringof);

template Bar1(T)
{
 const char[] Bar1 = T.stringof;
}
template Bar2(T)
{
 const char[] Bar2 = (T).stringof;
}

pragma(msg, `Bar1!(Foo!("a")): ` ~ Bar1!(Foo!("a")));
pragma(msg, `Bar1!(Foo!("b")): ` ~ Bar1!(Foo!("b")));
pragma(msg, `Bar2!(Foo!("a")): ` ~ Bar2!(Foo!("a")));
pragma(msg, `Bar2!(Foo!("b")): ` ~ Bar2!(Foo!("b")));

void main() {}
-----------------------------------

Compiler output:
-----------------------------------
Foo!("a").stringof: class Foo
Foo!("b").stringof: class Foo
(Foo!("a")).stringof: Foo
(Foo!("b")).stringof: Foo
Bar1!(Foo!("a")): Foo
Bar1!(Foo!("b")): Foo
Bar2!(Foo!("a")): Foo
Bar2!(Foo!("b")): Foo
-----------------------------------

Odder still, notice the "class " prepended to a couple of them.

stringof truly is shit atm.

"Nick Sabalausky" <a@a.a> wrote in message news:hff1qc$1h6e$1@digitalmars.com...
>I don't suppose there's an easy general way to get the paramaters of a templated type just from the type itself? Ie, a way to get around this:
>
> class Foo(char[] str) {}
> static assert(Foo!("a").stringof != Foo!("b").stringof)
> // ^ fails because it evaluates to "Foo" != "Foo"
>
> I can probably work around it in my current case by sticking str into a const member of Foo and using that together with .stringof, but thought I'd see if there was a better way.
>
>

Just for reference for anyone interested, in my own case I've worked around it like this:

class Foo(char[] str)
{
    static const char[] StringOf = "Foo!("~str.stringof~")";
}
static assert(Foo!("a").StringOf == `Foo!("a")`);

Similar workarounds can be done for other template signatures, like a custom-made function for enums, or a "static if(StringOf exists) use StringOf else use stringof" for general T types.