On Saturday, 23 April 2016 at 20:06:39 UTC, xtreak wrote:
map takes lambda as a template parameter and so does filter and
many other functions. Sometimes they take something other than
lambda as a template parameter. Eg. In case of to!int("5") int
is a type and hence might need it as a template parameter but
why does map and others take it as template parameter.
Adam D Ruppe pointed out in IRC it helps in inlining and
optimization. Is there a thumb rule to decide this so that my
functions too can benefit the performance and hence I could
structure and understand my code better.
Non-template function parameters can not be inlined, since
they're not determinable at compile-time, only at run-time.
You can have two versions if you want, one with the function as a
template parameter, and one with it as a function pointer.
I don't really think there is a rule of thumb to it other than
using templates when you desire performance and also nicer syntax
(in my opinion).
Templates also use up more space in the executable by the way, so
if you're developing on a platform with very limited memory, then
function pointers may be the better alternative.
