[upghost]

I will concede that my tone was not as welcoming or polite as it should be and could rightly be considered combative, so please accept my apologies.

> call_direct_and_indirect(IndirectCallTarget, Input, Result) :- call_direct(Input, Intermediate), % first-class call call(IndirectCallTarget, Intermediate, Result). % second-class call

I see we are at an unfortunate impasse. I assert what you are calling a "second-class call" is usually considered "first-class". I will leave the definition here for readers to decide for themselves. I rest my case and wish you a good day.

https://en.wikipedia.org/wiki/First-class_function

> Higher-order functions: passing functions as arguments

  Further information: Higher-order function
  In languages where functions are first-class citizens, functions can be passed 
  as arguments to other functions in the same way as other values (a function 
  taking another function as argument is called a higher-order function). In the 
  language Haskell:

  map :: (a -> b) -> [a] -> [b]
  map f []     = []
  map f (x:xs) = f x : map f xs