Unclear docs about Lists, "(x :: xs)"

[henrik]

Hi!

Noticed that

core/src/List.elm

Line 509 in 6656248

**Note:** It is usually preferable to use a `case` to test this so you do not

and some other places in the List docs are unclear to me and a co-worker.

Note: It is usually preferable to use a case to test this so you do not forget to handle the (x :: xs) case as well!

We understand that x :: xs has to do with seeing a list as head and tail, but don't get how that applies in this case.

[miniBill]

The docs are suggesting that you are probably better off writing

case list of
    [] -> ...
    (x::xs) -> ...

instead of

if List.isEmpty list then
    ...
else
    ....

[henrik]

Ah! So with x::xs as a way of matching a non-empty list. Think I get it, then. If I can think of a way to clarify this in the docs I’ll make a PR. Thank you!

[henrik]

I'll still try to make that PR, but before that, I thought I'd check something:

Is the naming x :: xs a convention in Elm – if my PR changed those docs (and maybe the code as well?) to say head :: tail, how would that be received? To me, that'd be clearer and likely easier to Google if needed.