Newline inconsistency in object expression

[MangelMaxime]

Issue created from fantomas-online

Code

let helpers =
    { new IDecoderHelpers<JToken> with
        member _.isString jsonValue =
            not (isNull jsonValue) && jsonValue.Type = JTokenType.String
        member _.asFloat jsonValue = jsonValue.Value<float>()
        member _.asInt jsonValue = jsonValue.Value<int>()
        member _.getObjectKeys jsonValue =
            jsonValue.Value<JObject>().Properties()
            |> Seq.map (fun prop -> prop.Name)
        member _.getField(fieldName: string, jsonValue: JToken) = jsonValue[fieldName]

    }

let helpers2 =
    { new IDecoderHelpers<JToken> with
        member _.anyToString jsonValue =
            if isNull jsonValue then
                "null"
            else
                use stream = new StringWriter(NewLine = "\n")

                stream.ToString()
    }

Result

let helpers =
    { new IDecoderHelpers<JToken> with
        member _.isString jsonValue =
            not (isNull jsonValue) && jsonValue.Type = JTokenType.String

        member _.asFloat jsonValue = jsonValue.Value<float>()
        member _.asInt jsonValue = jsonValue.Value<int>()

        member _.getObjectKeys jsonValue =
            jsonValue.Value<JObject>().Properties() |> Seq.map (fun prop -> prop.Name)

        member _.getField(fieldName: string, jsonValue: JToken) = jsonValue[fieldName]

    }

let helpers2 =
    { new IDecoderHelpers<JToken> with
        member _.anyToString jsonValue =
            if isNull jsonValue then
                "null"
            else
                use stream = new StringWriter(NewLine = "\n")

                stream.ToString() }

Problem description

I believe it would be better if there was a new line between each member, this would make the code more consistent. I think that if all the member are single line then not having a new line is fine.

Also, the placement of the trailing } is not always placed on a new line. I don't know what triggers that because in my project, I have a similar code as the member _.anyToString jsonValue = method and the } is placed on a new line and indented under the leading {.

Extra information

• [ ] The formatted result breaks my code.
• [ ] The formatted result gives compiler warnings.
• [ ] I or my company would be willing to help fix this.
• [ ] I would like a release if this problem is solved.

Options

Fantomas main branch at 1/1/1990

    { config with
                AlternativeLongMemberDefinitions = true
                MultiLineLambdaClosingNewline = true }

_{Did you know that you can ignore files when formatting by using a .fantomasignore file? PS: It's unlikely that someone else will solve your specific issue, as it's something that you have a personal stake in.}

[nojaf]

Hi there,

I believe it would be better if there was a new line between each member, this would make the code more consistent. I think that if all the member are single line then not having a new line is fine.

This is a topic for the style guide.

Also, the placement of the trailing } is not always placed on a new line.

In helpers, } is placed on a new line because it had a blank line before it. That was preserved from the original code. This works as expected.

[MangelMaxime]

In helpers, } is placed on a new line because it had a blank line before it. That was preserved from the original code. This works as expected.

You say that } is placed on a new line because there is blank line before however the following snippet results in the same formatting:

let helpers =
    { new IEncoderHelpers<JToken> with
        member _.encodeUInt32 value = JValue(box value) }

let helpers2 =
    { new IEncoderHelpers<JToken> with
        member _.encodeUInt32 value = JValue(box value) 
    }

Result

let helpers =
    { new IEncoderHelpers<JToken> with
        member _.encodeUInt32 value = JValue (box value)
    }

let helpers2 =
    { new IEncoderHelpers<JToken> with
        member _.encodeUInt32 value = JValue (box value)
    }

In both cases the } is pushed to a new line under the leading {.

Options

[*.{fs,fsx}]
max_line_length = 80
fsharp_space_before_uppercase_invocation = true
fsharp_alternative_long_member_definitions = true
fsharp_multi_line_lambda_closing_newline = true
fsharp_bar_before_discriminated_union_declaration = true
fsharp_multiline_bracket_style = stroustrup
fsharp_keep_max_number_of_blank_lines = 2

[nojaf]

Oh, I see. Your original report did not mention fsharp_multiline_bracket_style = stroustrup.

Stroustrup cannot be applied in absolutely every situation. I was convinced that

let x = { new System.IDisposable with
  member _.Dispose () = ()
}

was invalid code. (Producing an offset error). In certain situations it can lead to invalid code.

This does not seem the case. I am pretty sure we decided against this for object expressions. @josh-degraw does this ring a bell?

So, we could double-check whether is indeed possible for object expressions. If so, someone adds support for it. If not, we document that stroustrup cannot be used absolutely everywhere.

[josh-degraw]

Yeah that's sounds correct to me as far as what we did. However, wouldn't something like this be valid if we wanted to more strictly apply Stroustrup here?

let x = { 
    new System.IDisposable with
        member _.Dispose () = ()
}

This would be how I would expect Stroustrup style to be applied here.

[nojaf]

If it always leads to valid code, I'd be ok with this. It really rings a bell that this wasn't the case. Can't immediately find any prior art though.

[nojaf]

It is mentioned in the style guide. Guess this is possible.

[MangelMaxime]

Oh, I see. Your original report did not mention fsharp_multiline_bracket_style = stroustrup.

Ah yes sorry, I have a hard time finding which settings I have setup locally and not in the online tool.