what is the reason for allowing this

template test(char[] bla)
{
...
}


but not

template test(int[] bla)
{
...
}

or other bultin(own) types?

ciao dennis

dennis luehring wrote:
> what is the reason for allowing this
> 
> template test(char[] bla)
> {
> ....
> }
> 
> 
> but not
> 
> template test(int[] bla)
> {
> ....
> }
> 
> or other bultin(own) types?
> 
> ciao dennis


I'm with you on this.

see this:
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=53939

dennis luehring wrote:
> what is the reason for allowing this
> 
> template test(char[] bla)
> {
> ...
> }
> 
> 
> but not
> 
> template test(int[] bla)
> {
> ...
> }
> 
> or other bultin(own) types?
> 
> ciao dennis

I agree that it doesn't make sense, but you can do this hack:

template test(T...)
{
    static assert(is(typeof(T[0]) == int[]));
    const int[] bla = T[0];
}


   -- Reiner

dennis luehring wrote:
> what is the reason for allowing this
> 
> template test(char[] bla)
> {
> ....
> }
> 
> 
> but not
> 
> template test(int[] bla)
> {
> ....
> }
> 
> or other bultin(own) types?
> 
> ciao dennis

I think it's because arguments to a template become part of its mangled name.  Integers and floats are easy, as are actual strings, but to support arbitrary types, Walter would either need some kind of generic serialisation setup, or find a new way of mangling templates.

At least, that's how I understand it :)

	-- Daniel

-- 
int getRandomNumber()
{
    return 4; // chosen by fair dice roll.
              // guaranteed to be random.
}

http://xkcd.com/

v2sw5+8Yhw5ln4+5pr6OFPma8u6+7Lw4Tm6+7l6+7D i28a2Xs3MSr2e4/6+7t4TNSMb6HTOp5en5g6RAHCP  http://hackerkey.com/

Daniel Keep wrote:
> 
> dennis luehring wrote:
>> what is the reason for allowing this
>>
>> template test(char[] bla)
>> {
>> ....
>> }
>>
>>
>> but not
>>
>> template test(int[] bla)
>> {
>> ....
>> }
>>
>> or other bultin(own) types?
>>
>> ciao dennis
> 
> I think it's because arguments to a template become part of its mangled
> name.
Yes.
>  Integers and floats are easy, as are actual strings, but to
> support arbitrary types, Walter would either need some kind of generic
> serialisation setup, or find a new way of mangling templates.

That's not much of an issue. In fact, if you look at the ABI page, you'll see that the mangling scheme almost supports arbitrary types already.

TemplateArg:
    T Type
    V Type Value
    S LName
Any type which can be a type template parameter, and which has literals, could also be a value parameter.

The problem is that the mangled names become too long, which makes bad things happen (eg, the obj file format imposes a maximum identifier length of ~ 3kB).
There a few types (int[], short[] ubyte[]) which are essentially identical to the permitted dchar[], wchar[], char[], and could trivially be permitted.

CTFE has drastically reduced the number of cases where it would be useful, though.