pipe operator · beginners · Zulip Chat Archive

@Richard Feldman I meant to ask the other day about why you chose to go with |> instead of . as the pipe operator? Especially considering I've seen Koka mentioned in the GitHub repo at least once or twice.

Folkert de Vries (Oct 18 2021 at 18:06):

|> indicates direction, and we already use . for record fields are two reasons

Folkert de Vries (Oct 18 2021 at 18:07):

we use reference counting tricks implemented in koka, and later found out they also do what we call "backpassing" but I have to admit I never actually ran any koka code

Lucas Rosa (Oct 18 2021 at 18:10):

|> being the pipe operator is fairly common for FP languages. Elixir and Elm are two off the top of my head

Folkert de Vries (Oct 18 2021 at 18:15):

purescript too I believe, at least you can use it there, f# is another example

Lucas Rosa (Oct 18 2021 at 18:43):

yea it's an extensive list :p

Lucas Rosa (Oct 18 2021 at 18:43):

. in haskell is function composition if I remember correctly

Folkert de Vries (Oct 18 2021 at 18:44):

yes

Folkert de Vries (Oct 18 2021 at 18:44):

interestingly, Clean uses the letter o for that purpose

Folkert de Vries (Oct 18 2021 at 18:44):

one of its many quirks

Wolfgang Schuster (Oct 18 2021 at 19:37):

I kinda guessed these were the reasons, but figured it was worth asking in case there was something else. Can likely add JS to the list of languages that use |> too once the proposal gets fully accepted

Richard Feldman (Oct 18 2021 at 20:17):

yeah, I think that one seems to be well on the road to standardization...except when it comes to argument order :sweat_smile:

Richard Feldman (Oct 18 2021 at 20:18):

|> in Elixir and Roc makes the preceding value be the first argument, whereas in Elm and F# it's the last argument. Last I heard, JS was debating between "first argument" and "explicit placeholder symbol for where you want it to go"