Implement MaxBindingWidth for members

Implements the MaxBindingWidth setting for member values and
member functions and adds test cases.

src/Fantomas.Tests/AttributeTests.fs

@@ -16,7 +16,8 @@ type Funcs =
     |> should equal """[<Extension>]
 type Funcs =
     [<Extension>]
-    static member ToFunc(f: Action<_, _, _>) = Func<_, _, _, _>(fun a b c -> f.Invoke(a, b, c))
+    static member ToFunc(f: Action<_, _, _>) =
+        Func<_, _, _, _>(fun a b c -> f.Invoke(a, b, c))
 """
 
 [<Test>]

src/Fantomas.Tests/Fantomas.Tests.fsproj

@@ -69,6 +69,7 @@
     <Compile Include="MultilineBlockBracketsOnSameColumnArrayOrListTests.fs" />
     <Compile Include="NewlineBetweenTypeDefinitionAndMembersTests.fs" />
     <Compile Include="KeepIfThenInSameLineTests.fs" />
+    <Compile Include="MaxBindingWidthTests.fs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Fantomas\Fantomas.fsproj" />

src/Fantomas.Tests/MaxBindingWidthTests.fs

@@ -0,0 +1,83 @@
+module Fantomas.Tests.MaxBindingWidthTests
+
+open NUnit.Framework
+open FsUnit
+open Fantomas.Tests.TestHelper
+
+let config = { config with MaxBindingWidth = 20 }
+
+[<Test>]
+let ``should apply to value definition``() =
+    formatSourceString false """let a = bbbbbbbbbbbbbbbbbbbbbbbbbb""" config
+    |> should equal """let a =
+    bbbbbbbbbbbbbbbbbbbbbbbbbb
+"""
+
+[<Test>]
+let ``should not apply to short value definition``() =
+    formatSourceString false """let a = b""" config
+    |> should equal """let a = b
+"""
+
+[<Test>]
+let ``should apply to function definition``() =
+    formatSourceString false """let a bbbbbbbbbbbbbbbbbbbbbbbbbb = bbbbbbbbbbbbbbbbbbbbbbbbbb + 1""" config
+    |> should equal """let a bbbbbbbbbbbbbbbbbbbbbbbbbb =
+    bbbbbbbbbbbbbbbbbbbbbbbbbb + 1
+"""
+
+[<Test>]
+let ``should not apply to short function definition``() =
+    formatSourceString false """let a b = b + 1""" config
+    |> should equal """let a b = b + 1
+"""
+
+[<Test>]
+let ``should apply to member value definition``() =
+    formatSourceString false """type T =
+    let aaaaaaaaaaaaaaaaaaaa = bbbbbbbbbbbbbbbbbbb + 1
+    member this.ccccccccccccccccccccccccccccccc = dddddddddddddddddddddddddddd + 2
+    """ config
+    |> should equal """type T =
+    let aaaaaaaaaaaaaaaaaaaa =
+        bbbbbbbbbbbbbbbbbbb + 1
+
+    member this.ccccccccccccccccccccccccccccccc =
+        dddddddddddddddddddddddddddd + 2
+"""
+
+[<Test>]
+let ``should not apply to short member value definition``() =
+    formatSourceString false """type T =
+    let a = b + 1
+    member this.c = d + 2
+    """ config
+    |> should equal """type T =
+    let a = b + 1
+    member this.c = d + 2
+"""
+
+[<Test>]
+let ``should apply to member function definition``() =
+    formatSourceString false """type T =
+    let aaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbb = bbbbbbbbbbbbbbbbbbb + 1
+    member this.cccccccccccccc dddddddddddddd = dddddddddddddd + 2
+    """ config
+    |> should equal """type T =
+    let aaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbb =
+        bbbbbbbbbbbbbbbbbbb + 1
+
+    member this.cccccccccccccc dddddddddddddd =
+        dddddddddddddd + 2
+"""
+
+[<Test>]
+let ``should not apply to short member function definition``() =
+    formatSourceString false """type T =
+    let a b = b + 1
+    member this.c d = d + 2
+    """ config
+    |> should equal """type T =
+    let a b = b + 1
+    member this.c d = d + 2
+"""

src/Fantomas.Tests/TypeDeclarationTests.fs

@@ -896,7 +896,8 @@ type TestExtensions =
     static member SomeExtension(x) = ""
 
     [<Extension>]
-    static member SomeOtherExtension(x) = ""
+    static member SomeOtherExtension(x) =
+        ""
 """
 
 [<Test>]

src/Fantomas/CodePrinter.fs

@@ -685,15 +685,15 @@ and genMemberBinding astContext b =
                 ifElse
                     prefixIsLong
                     (indent +> sepNln +> sepColon +> genType astContext false t +> sepNln +> !- "=" +> sepNln +> genExpr astContext e +> unindent)
-                    (sepColon +> genType astContext false t +> sepEq +> sepSpaceOrIndentAndNlnIfExpressionExceedsPageWidth (genExpr astContext e)))
+                    (sepColon +> genType astContext false t +> sepEq +> sepSpaceOrIndentAndNlnIfExpressionExceedsMaxBindingWidthIgnoreShort (genExpr astContext e)))
         | e ->
             genAttributesAndXmlDoc
             +> leadingExpressionIsMultiline prefix
                 (fun prefixIsLong ->
                     ifElse
                         prefixIsLong
                         (indent +> sepNln +> !- "=" +> sepNln +> genExpr astContext e +> unindent)
-                        (sepEq +> sepSpaceOrIndentAndNlnIfExpressionExceedsPageWidth (genExpr astContext e)))
+                        (sepEq +> sepSpaceOrIndentAndNlnIfExpressionExceedsMaxBindingWidthIgnoreShort (genExpr astContext e)))
 
     | ExplicitCtor(ats, px, ao, p, e, so) ->
         let prefix =

src/Fantomas/Context.fs

@@ -567,21 +567,21 @@ let internal leadingExpressionIsMultiline leadingExpression continuationExpressi
     let hasWriteLineEventsAfterExpression = contextAfterLeading.WriterEvents |>Seq.skip eventCountBeforeExpression |> Seq.exists (function | WriteLine _ -> true | _ -> false)
     continuationExpression hasWriteLineEventsAfterExpression contextAfterLeading
 
-let private expressionExceedsPageWidth beforeShort afterShort beforeLong afterLong expr (ctx: Context) =
+let private expressionExceedsWidth width ignoreShort beforeShort afterShort beforeLong afterLong expr (ctx: Context) =
     // if the context is already inside a ShortExpression mode, we should try the shortExpression in this case.
     match ctx.WriterModel.Mode with
-    | ShortExpression _ ->
+    | ShortExpression _ when not ignoreShort ->
         // if the context is already inside a ShortExpression mode, we should try the shortExpression in this case.
         (beforeShort +> expr +> afterShort) ctx
     | _ ->
-        let shortExpressionContext = ctx.WithShortExpression(ctx.Config.PageWidth, 0)
+        let shortExpressionContext = ctx.WithShortExpression(width, 0)
         let resultContext = (beforeShort +> expr +> afterShort) shortExpressionContext
         let fallbackExpression = beforeLong +> expr +> afterLong
 
         match resultContext.WriterModel.Mode with
         | ShortExpression info ->
             // verify the expression is not longer than allowed
-            if info.ConfirmedMultiline || info.IsTooLong ctx.Config.PageWidth resultContext.Column
+            if info.ConfirmedMultiline || info.IsTooLong width resultContext.Column
             then fallbackExpression ctx
             else
                 { resultContext with WriterModel = { resultContext.WriterModel with Mode = ctx.WriterModel.Mode } }
@@ -592,19 +592,32 @@ let private expressionExceedsPageWidth beforeShort afterShort beforeLong afterLo
 /// try and write the expression on the remainder of the current line
 /// add an indent and newline if the expression is longer
 let internal autoIndentAndNlnIfExpressionExceedsPageWidth expr (ctx:Context) =
-    expressionExceedsPageWidth
+    expressionExceedsWidth
+        ctx.Config.PageWidth false
         sepNone sepNone // before and after for short expressions
         (indent +> sepNln) unindent // before and after for long expressions
         expr ctx
 
-let internal sepSpaceOrIndentAndNlnIfExpressionExceedsPageWidth expr (ctx:Context) =
-    expressionExceedsPageWidth
+let internal sepSpaceOrIndentAndNlnIfExpressionExceedsWidth width expr (ctx:Context) =
+    expressionExceedsWidth
+        width false
+        sepSpace sepNone // before and after for short expressions
+        (indent +> sepNln) unindent // before and after for long expressions
+        expr ctx
+
+let internal sepSpaceOrIndentAndNlnIfExpressionExceedsMaxBindingWidthIgnoreShort expr (ctx:Context) =
+    expressionExceedsWidth
+        ctx.Config.MaxBindingWidth true
         sepSpace sepNone // before and after for short expressions
         (indent +> sepNln) unindent // before and after for long expressions
         expr ctx
 
+let internal sepSpaceOrIndentAndNlnIfExpressionExceedsPageWidth expr (ctx:Context) =
+    sepSpaceOrIndentAndNlnIfExpressionExceedsWidth ctx.Config.PageWidth expr ctx
+
 let internal autoNlnIfExpressionExceedsPageWidth expr (ctx: Context) =
-    expressionExceedsPageWidth
+    expressionExceedsWidth
+        ctx.Config.PageWidth false
         sepNone sepNone // before and after for short expressions
         sepNln sepNone // before and after for long expressions
         expr ctx
@@ -936,7 +949,8 @@ let internal sepNlnTypeAndMembers (firstMemberRange: range option) ctx =
         ctx
 
 let internal autoNlnConsideringTriviaIfExpressionExceedsPageWidth expr range (ctx: Context) =
-    expressionExceedsPageWidth
+    expressionExceedsWidth
+        ctx.Config.PageWidth false
         sepNone sepNone // before and after for short expressions
         (sepNlnConsideringTriviaContentBefore range) sepNone // before and after for long expressions
         expr ctx