Re: Passing anonymous templated functions as template parameters

[Basile B. via Digitalmars-d-learn]

On Wednesday, 15 June 2016 at 23:52:56 UTC, Basile B. wrote:

On Wednesday, 15 June 2016 at 22:27:38 UTC, pineapple wrote:
Here's a simple code example to illustrate what I expected to 
work and didn't - is this a mistake in my syntax or a 
limitation of the language?


template SomeTemplate(alias func){
auto templatefunc(T)(int x){
return func!T(x);
}
}

// Valid
auto somefunc(T)(int x){
return cast(T) x;
}
alias fn1 = SomeTemplate!somefunc;

// Not valid
alias fn2 = SomeTemplate!(
(T)(int x){return cast(T) x;}
);


This syntax passes:

alias fn2(T) = SomeTemplate!((int x){return cast(T) x;});


I didn't try to instanciate previously. It works a bit with a 
lambda to the

extent that the alias has the template parameter list.

import std.stdio;

template A(alias func)
{
auto a(T)(int x)
{
return func!T(x);
}
}

alias spec(T) = A!(x => (cast(T) x));

void main(string[] args)
{
writeln((spec!byte).a!int(257)); // 1
}

Re: Passing anonymous templated functions as template parameters

[Steven Schveighoffer via Digitalmars-d-learn]

On 6/15/16 7:52 PM, Basile B. wrote:

On Wednesday, 15 June 2016 at 22:27:38 UTC, pineapple wrote:

Here's a simple code example to illustrate what I expected to work and
didn't - is this a mistake in my syntax or a limitation of the language?

template SomeTemplate(alias func){
auto templatefunc(T)(int x){
return func!T(x);
}
}

// Valid
auto somefunc(T)(int x){
return cast(T) x;
}
alias fn1 = SomeTemplate!somefunc;

// Not valid
alias fn2 = SomeTemplate!(
(T)(int x){return cast(T) x;}


This isn't valid syntax.

I don't think you can create anonymous templates. I could be wrong.

-Steve

Re: Passing anonymous templated functions as template parameters

[Basile B. via Digitalmars-d-learn]

On Wednesday, 15 June 2016 at 22:27:38 UTC, pineapple wrote:
Here's a simple code example to illustrate what I expected to 
work and didn't - is this a mistake in my syntax or a 
limitation of the language?


template SomeTemplate(alias func){
auto templatefunc(T)(int x){
return func!T(x);
}
}

// Valid
auto somefunc(T)(int x){
return cast(T) x;
}
alias fn1 = SomeTemplate!somefunc;

// Not valid
alias fn2 = SomeTemplate!(
(T)(int x){return cast(T) x;}
);


This syntax passes:

alias fn2(T) = SomeTemplate!((int x){return cast(T) x;});

Passing anonymous templated functions as template parameters

[pineapple via Digitalmars-d-learn]

Here's a simple code example to illustrate what I expected to 
work and didn't - is this a mistake in my syntax or a limitation 
of the language?


template SomeTemplate(alias func){
auto templatefunc(T)(int x){
return func!T(x);
}
}

// Valid
auto somefunc(T)(int x){
return cast(T) x;
}
alias fn1 = SomeTemplate!somefunc;

// Not valid
alias fn2 = SomeTemplate!(
(T)(int x){return cast(T) x;}
);