Avoid indentation of `fun`.

[dbuenzli]

@drup wants to be able to write:

val f : t1 -> t2 -> t3
let f x y z = ...

at which @chris00 responds you can write:

let f : t1 -> t2 -> t3 =
  fun x y z -> ...

which I'd gladly use (e.g. in blog posts I write things like @drup but then it makes the code not easily copy pastable in bulk). However I'm sad to loose what is going to be likely 4 columns (assuming the function spans more than one line). Would it be possible to avoid the fun indentation ?

let f : t1 -> t2 -> t3 =
fun x y z -> ...

(at which point you realize github's syntax higlighting is indentation aware)

[Drup]

In practice when doing gadt things, you are forced to write it like that, so yes, that would be nice.

[Chris00]

FWIW, Tuareg indents it like:

let f : t1 -> t2 -> t3 =
  fun x y z ->
  xxx

so you do not have a 4 columns indent.

[dbuenzli]

I miss this (non)indentation rule a lot.

[dbuenzli]

Thanks !