i wanted to know how Y-combinator works, so i wrote one with c++ metafunctions.

Y-combinator

Y-combinator is a method of performing recursion without self-reference.

Z-combinator

the standard definition however doesn't work for applicative order languages. so an alternative form needs to be used that is usually called a Z-combinator.

c++ meta-function

a meta-function is a type that contains a template alias. this type can be then passed as a type parameter to templates like other meta-functions. using meta-function is much more flexible and powerful that what can be achieved by using template template parameters.