How to deal with multiline expressions in parens

[avh4]

How should the following be formatted?

foo x =
    ( case x of
        Just a ->
            a
        _ ->
            7
    )
        |> toString

[Apanatshka]

I'm pretty sure the offside rule allows you to write this without the round brackets... Something like:

foo x =
    case x of
        Just a ->
            a
        _ ->
            7
    |> toString

I prefer my pipelines aligned, rather than indented anyway.

[avh4]

This isn't exactly it, but I think there must be cases where the parens are required:

foo x =
    CtorWithTwoParams
        ( case x of
            Just a ->
                a
            _ ->
                7
        )
        "second param"

[Apanatshka]

Yes, a case as a parameter will need to be wrapped in parentheses I guess. I'm ok this the style from your example. You simply shouldn't use case expressions there, so the formatter punishes you by giving an ugly piece of code (that's still very readable).

[rtfeldman]

Following this proposed rule, all I'd change would be removing the space after the open paren:

foo x =
    (case x of
        Just a ->
            a
        _ ->
            7
    )
        |> toString

Neither of them looks great, but this has the benefit of the rule being simpler to explain. 😉

[avh4]

Using no space leads to:

multilineParenthesizedExpressions =
    (if range == 0 then
        0.1
      else
        toFloat range
    )

where the if and else are not aligned!

[rtfeldman]

Following this idea would solve this too:

foo x =
    (
        case x of
            Just a ->
                a

            _ ->
                7
    )
        |> toString

[avh4]

We'll go with #20 for now. The it ended up working, the following case will actually keep if and else aligned:

multilineParenthesizedExpressions =
    (if range == 0 then
        0.1
     else
        toFloat range
    )