Flattening Combinators: Surviving Without Parentheses [pdf]

Oh cool! This immediately made me think of Joy.

My complaint with |> is that it makes code with nesting look quite different based on argument position. Argument position is not a very interesting property, so it doesn't seem right for it to be influencing the shape of code in that way.

My preference is to use parens and introduce single-shot variables if nesting gets too deep. This works the same way for all code.

Ocaml has had the @@ operator for a while, which is |> with it's arguements inversed, so you could write "print_int(2+3)" or "print_int @@ 2+3". Haskell is in a similar place, with the $ operator (equivalent to @@), but no |> in the standard library [0]. The main issue is that for a lot of people, there just isn't that much of a benefit to composing function left to right, as apposed to right to left; especially since the "simple" way of just using parentheses gives us right to left composition.

[0] If you want this, check out the flow package https://hackage.haskell.org/package/flow-1.0.8/docs/Flow.htm...

I believe the |> operator has been around for a while -- I've seen it used in some older Standard ML code, but just as a user-defined operator and not part of the basis library. F# included it in the core library for the language and it was fairly popular there for structuring heavily-nested expressions into a more-human-readable "pipeline". OCaml added it to the Core library fairly recently, as has (I believe) Elixir.