Function Pointers with Type T

[Adam D. Ruppe via Digitalmars-d-learn]

You can get the code to compile with two changes:

bool function(T)(T val1,T val2) ptr=∁

should be:

bool function(T val1,T val2) ptr=&comp!T;



The function pointer itself isn't a template, so it doesn't need 
the (T) parameter. Instead, since it is inside a template, you 
can just use the T from the outside directly.

Moreover, comp has compile time arguments, so you can't take the 
address of it without forwarding the arguments. So instead of 
&comp, you use &comp!T - passing the T from the outside to the 
comparison function too.

and also

int partition(T)(T[]list,bool function(T)(T val1,T val2)ptr,int

should be:

int partition(T)(T[]list,bool function(T val1,T val2)ptr,int


Again because the pointer isn't a new template, it should just 
use the type T from the outer argument list.