On Tue, Nov 16, 2010 at 3:26 PM, Michael Ekstrand <michael@elehack.net> wrote:
Batteries provides operators for things like this. It defines the '**>'
operator for function application; it's an odd name, but it has the
right associativity. As Dmitry mentioned, some override (&). Batteries
also provides composition operators |- and -|, and a pipeline operator
|> (opposite of **>). With that operator, you can write:
f x y |> ignore
thereby putting the emphasis on "f x y" and relegating "ignore" to a
cleanup at the end.
- Michael
(<|) as inverse of (|>) is also available. It doesn't have the "right" associativity, but you can easily use (f -| g -| h <| x) instead of (f **> g **> h **> x).
Though I find the application-as-pipeline style quite readable in some cases, I think that in general it is more often superfluous than not. Besides, as mentioned recently on this list, overuse of the function composition operators (|-) and (-|) are also call for troubles with the value restriction.
All in all, I think it's reasonable to stay conservative and not advertise funky binary operators too loudly.
That said, domain-specific binary operators are certainly useful for readability in some contexts --- that's what an infix operator is anyway : an unreadable-by-design symbol that only get meaning by domain-specific conventions. Local open in, available by standard since OCaml 3.12, allow us to neatly encapsulate such domain-specific notations into OCaml modules.