Breaking method chain in the middle of an if statement causes offside error

[Smaug123]

Issue created from fantomas-online

Code

module Foo =
    let bar =
        if Regex("long long long long long long long long long").Match(s).Success then
            None
        else Some "hi"

Result

module Foo =
    let bar =
        if Regex(
            "long long long long long long long long long"
        )
            .Match(
            s
        )
            .Success then
            None
        else
            Some "hi"

Problem description

Not really sure what the best format here would be. Maybe:

if Regex("long long long…")
    .Match(s)
    .Success then
    None
else
    Some "hi"

assuming that actually compiles.

Extra information

• The formatted result breaks by code.
• The formatted result gives compiler warnings.
• I or my company would be willing to help fix this.

Options

Fantomas Master at 05/09/2021 13:45:10 - f10b822

Default Fantomas configuration

_{Did you know that you can ignore files when formatting from fantomas-tool or the FAKE targets by using a .fantomasignore file?}

[nojaf]

Maybe be can go with

module Foo =
    let bar =
        if
            Regex(
                "long long long long long long long long long"
            )
                .Match(
                s
            )
                .Success
        then
            None
        else
            Some "hi"

as suggested in the MS style guide here.

What do you think? It would be easy to get around those offset errors that way.

[Smaug123]

Oof, I find that extremely ugly, I'm afraid! @TobyShaw I don't suppose you have any cunning ideas here?

[nojaf]

Well I feel like there are two parts to this:

1. How Fantomas deals with the expression
2. What Fantomas should do in case the if expression is long or funky.

As for 1:

Regex(
    "long long long long long long long long long"
)
    .Match(s)
    .Success

might be an option.

When it comes to 2, I do like the

if
    longExpression
then
    // ...

style, it nicely highlights that you may wanted to go with a intermediate let binding instead.
And it also has a bit of rhyme with try/with or match/with, though indeed quite far fetched.
Any chance that helps? I'm open for feedback here, life is easier with my proposal for 2 as it plays better with the offset rules.

[Smaug123]

I guess in real life an expression that is long and complex enough to format this way is going to get changed at review time.

I think I agree with both your suggestions 1 and 2; it's just the implied combination that makes me sad :P perhaps it's fine, though, and we'll just have an informal rule saying "you should never write code that falls into this case".