Options for trailing commas

[andyli]

I would like to specify whether a trailing comma should be added for the last array element.

e.g.

// no trailing comma
[
    1,
    2,
    3
];

// with trailing comma
[
    1,
    2,
    3,
];

Not sure if it's already possible?

[Gama11]

The formatter does currently not insert or remove tokens.

[andyli]

Do you mean it's not possible to implement (without major changes)?

[Gama11]

Not sure about "major" changes, @AlexHaxe probably has a better idea on that, but definitely not as straightforward as it might seem (ranges of subsequent tokens would have to be updated at the very least).

[AlexHaxe]

Currently formatter only deals with removal or addition of whitespace. It doesn't rearrange, add or delete tokens from your sources. Introducing a new token into or making edits to a parsed tokentree involves at least a) finding the correct spot and b) correcting token list and index values. Otherwise successive formatter stages will run into issues.

I would say it's not impossible to implement, but it might take some time to get it right.

Also I feel like that feature is more checkstyle territory. It would be a separate check which produces a diagnostic in VSCode, and a code action in checkstyle extension could offer a fix. Of course that works only on a file by file basis, where you have to open each file and apply fixes manually. I guess such a check makes sense independant of whether formatter learns that trick or not.

[Simn]

For what it's worth I agree that this is more of a checkstyle thing. I would keep haxe-formatter a whitespace rearrangement tool for the sake of the author's sanity.