Templated Function pointers

[js.mdnq]

I need to store a templated function in a function pointer, how 
can I do this?



e.g.,

void function(double) myfuncptr;
void myfunc(double d) { }
myfuncptr = myfunc;

Now I would like to use a template parameter instead of double.

In C++ one can do this by using boosts binding's and function 
types.


For example, I want something like this

void function(F)(F) funcptr;

void Bind(T)(void function(T)(T) v)
{
funcptr = v; // F is sort of deduced automatically as being 
T. Obviously problematic but effectively what I want to do.

}

This way I can bind to any function that takes a single type 
parameter and returns a void.



void function(F) myfuncptr;  // F is undefined
void myfunc(T)(T d) { }  //
myfuncptr = myfunc;

To do this using boost I would simply bind the parameter so 
myfuncptr would not depend on an arbitrary type.


I need a rather performant way to do this too.

Re: Templated Function pointers

[js.mdnq]

It seems one can accomplish this using delegates assigned by 
generic functions. The delegate will end hold holding the "state" 
of the function. It sort of acts like a binder. It seems to work 
but more testing needs to be done. I'm not sure how efficient it 
is or if there is a better way but basically it seems rather 
elegant(rather than trying to create some new type to deal with 
it).

Re: Templated Function pointers

[bearophile]

js.mdnq:

It seems one can accomplish this using delegates assigned by 
generic functions.


If you care so much for performance, when you work with D 
delegates it's useful to know the difference between static/scope 
delegates (that are just a fat pointer) and closures (that often 
induce a heap allocation).


Bye,
bearophile