Use Fun.id in the documentation of StdLabels

[favonia]

No description provided.

[nojb]

Hello, thanks for the suggestion. This is kind of subjective, but I find this change gratuitous: there is nothing wrong with the existing code, and the new code does not provide any real improvement either (and it introduces a "dependency" between StdLabels and Fun). All in all, it doesn't seem worth it. Thanks anyway!

[gasche]

My personal rule of the thumb is that Fun.id makes sense in terms that are formed of several combinators to describe transformations, for example Either.map ~left:f ~right:Fun.id, which goes from f : ('a -> 'b) to ('a, 'c) Either.t -> ('b, 'c) Either.t. (We already have a specialized map_left for this, but you get the point of the example.) On the other hand, I avoid it "at the toplevel", when the function I want to describe is the identity (I just write the more readable (fun i -> i); by the way, not sure why (function i -> i) is used here in the documentation, it sounds like a minor style mistake). I think that List.init is in a grey area where one could see it either ways, and in this case I tend to agree that avoiding functions that have to be known from the reader is the best choice.

[favonia]

Thanks! Should we change it to fun i -> i, then? I should explain that this PR was inspired by the new documentation on TMC, which uses Fun.id with List.init twice without explanation. I thus got the impression that the documentation of StdLabels could use an update. I don't have a strong opinion, and since I have brought this issue to your (the core developers') attention, I believe I have done my part and should leave further discussions to you.

[gasche]

Ouch! I wrote the TMC chapter, but I blame @dra27 on this one ( #10740 (comment) ).

In the present case I think that fun i -> i would certainly be an improvement over function i -> i. I only use function when there is a real pattern-matching at play.

[dra27]

Blame taken - but FWIW I prefer Fun.id 🙂 I wholeheartedly agree with only using function for pattern matching.