function-local template specialization error

[canalpay]

void main()
{
T input(T)()
{}
 
T input(T : string)()
{}
}

Error message :

isimsiz.d(6): found 'input' when expecting ';' following statement
isimsiz.d(6): found ':' when expecting ')'
isimsiz.d(6): found 'string' when expecting ';' following statement
isimsiz.d(6): found ')' instead of statement
isimsiz.d(8): unrecognized declaration
 
Shouldn't that work?

And

void main()
{
void input(T)()
{}
 
void input(T : string)()
{}
}

Again, Shouldn't that work?

Error message:
isimsiz.d(6): Error: declaration input(T : string) is already defined

there is no problem when the templates are in the global namespace.

Re: function-local template specialization error

[bearophile]

canalpay:
 void main()
 {
 T input(T)()
 {}
  
 T input(T : string)()
 {}
 }

In D2 you can't define templates inside functions.

Bye,
bearophile

Re: function-local template specialization error

[bearophile]

canalpay:
 Thanks, But this example works:
 void main()
 {
 T input(T)()
 {}
 
 }
 
  Why ?

You are right. Beside allowing nested functions (this is well known), it seems 
D2 also accepts the definition (with template constraint too) and instantiation 
of simple templates inside functions, I didn't know this.

But currently nested functions can't be overloaded. Probably for similar 
reasons inside a function you can't define more than one template with the same 
name. I presume this limit can be removed, so if you really need this you can 
ask for an enhancement request and if you can add a patch too to increase a bit 
the probability to see it fulfilled someday.

Bye,
bearophile

Re: function-local template specialization error

[Don]

bearophile wrote:

canalpay:

Thanks, But this example works:
void main()
{
T input(T)()
{}

}

 Why ?


You are right. Beside allowing nested functions (this is well known), it seems 
D2 also accepts the definition (with template constraint too) and instantiation 
of simple templates inside functions, I didn't know this.

But currently nested functions can't be overloaded. Probably for similar 
reasons inside a function you can't define more than one template with the same 
name. I presume this limit can be removed, so if you really need this you can 
ask for an enhancement request and if you can add a patch too to increase a bit 
the probability to see it fulfilled someday.

Bye,
bearophile


The spec explicitly says:
Unlike module level declarations, declarations within function scope 
are processed in order. This means that two nested functions cannot 
mutually call each other:


[snip]

Future directions: This restriction may be removed.

My guess is that it will become possible eventually.