pipeline vs composition

foo.hs

-- pipelining
let x = 1
    doubled = x * 2
    squared = doubled * doubled
    decremented = squared - 1
  in decremented
  
-- composition

let x = 1
    double = (*) 2
    square x = x * x
    decrement x = x - 1
  in (decrement . square . double) x

Yes, and the vital difference between them is that the composition version creates a new first-class that can be named, passed as a value, &tc., while the pipelined version does not. Furthermore, the composition version can be dynamically composed, while most languages have difficulty dynamically pipelining things.

Both do the exact same thing in the small, but the compositional version can be much better if there is some wonderful thing enabled by making something first-class. And it can be worse if that is a distraction to the primary responsibility fo the code.

@raganwald, Thanks for responding!

I'm not sure I understand the distinction. In this case, both let statements could just be the body of a first-class function, which could be named, passed around, composed, etc.

Maybe this example is just too small.