what is the point of functor ?

[Steven Schveighoffer]

On 6/22/18 10:06 AM, Flaze07 wrote:
> recently, I visited the glossary and saw that functor exist in D...I 
> know that functor exist C++ as a way to easily allow higher order 
> function, but since D already has function and delegates, is there a 
> point to functor ?

D covers a lot of programming paradigms. It has Java-like classes and 
interfaces, and C++-like functors, along with pure functions, (good) 
templates, immutable data, concurrency, etc.

It's meant to make it easy to transition to D from the language you are 
used to.

There's no specific reason to use functors, but if you want to, you can, 
as most of std.algorithm supports them (see 
https://dlang.org/phobos/std_traits.html#isCallable).

-Steve