Ensure parenthesis around multiline expression before dot - fix #246

src/Fantomas.Tests/ClassTests.fs

@@ -323,4 +323,43 @@ let ``class inherit and augmentation``() =
     with
         let hello = "Hello"
         member this.X = "Member"
+"""
+
+[<Test>]
+let ``property long line``() =
+    formatSourceString false """type T() =
+    member __.Property = "hello"
+let longNamedFunlongNamedFunlongNamedFunlongNamedFunlongNamedFun (x:T) = x
+let longNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClass = T()
+
+System.String.Concat("a", "b" + 
+                            longNamedFunlongNamedFunlongNamedFunlongNamedFunlongNamedFun(longNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClass).Property)
+"""  config
+    |> should equal """type T() =
+    member __.Property = "hello"
+
+let longNamedFunlongNamedFunlongNamedFunlongNamedFunlongNamedFun (x : T) = x
+let longNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClass =
+    T()
+
+System.String.Concat
+    ("a", 
+     "b" 
+     + (longNamedFunlongNamedFunlongNamedFunlongNamedFunlongNamedFun
+            (longNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClasslongNamedClass)).Property)
+"""
+
+[<Test>]
+let ``indexed get long line``() =
+    formatSourceString false """open System
+type Exception with
+    member inline __.FirstLine = 
+        __.Message.Split([|Environment.NewLine|], StringSplitOptions.RemoveEmptyEntries).[0]
+"""  config
+    |> should equal """open System
+
+type Exception with
+    member inline __.FirstLine =
+        (__.Message.Split
+             ([| Environment.NewLine |], StringSplitOptions.RemoveEmptyEntries)).[0]
 """

src/Fantomas/CodePrinter.fs

@@ -643,11 +643,12 @@ and genExpr astContext = function
     // At this stage, all symbolic operators have been handled.
     | OptVar(s, isOpt) -> ifElse isOpt (!- "?") sepNone -- s
     | LongIdentSet(s, e) -> !- (sprintf "%s <- " s) +> genExpr astContext e
-    | DotIndexedGet(e, es) -> genExpr astContext e -- "." +> sepOpenLFixed +> genIndexers astContext es +> sepCloseLFixed
-    | DotIndexedSet(e1, es, e2) -> genExpr astContext e1 -- ".[" +> genIndexers astContext es -- "] <- " +> genExpr astContext e2
+    | DotIndexedGet(e, es) -> addParenIfAutoNln e (genExpr astContext) -- "." +> sepOpenLFixed +> genIndexers astContext es +> sepCloseLFixed
+    | DotIndexedSet(e1, es, e2) -> addParenIfAutoNln e1 (genExpr astContext) -- ".[" +> genIndexers astContext es -- "] <- " +> genExpr astContext e2
     | DotGet(e, s) -> 
-        genExpr { astContext with IsInsideDotGet = true } e -- sprintf ".%s" s
-    | DotSet(e1, s, e2) -> genExpr astContext e1 -- sprintf ".%s <- " s +> genExpr astContext e2
+        let exprF = genExpr { astContext with IsInsideDotGet = true }
+        addParenIfAutoNln e exprF -- (sprintf ".%s" s)
+    | DotSet(e1, s, e2) -> addParenIfAutoNln e1 (genExpr astContext) -- sprintf ".%s <- " s +> genExpr astContext e2
     | LetOrUseBang(isUse, p, e1, e2) ->
         atCurrentColumn (ifElse isUse (!- "use! ") (!- "let! ") 
             +> genPat astContext p -- " = " +> genExpr astContext e1 +> sepNln +> genExpr astContext e2)

src/Fantomas/FormatConfig.fs

@@ -348,16 +348,19 @@ let internal sepOpenT = !- "("
 /// closing token of tuple
 let internal sepCloseT = !- ")"
 
-
-/// Set a checkpoint to break at an appropriate column
-let internal autoNlnOrAddSep f sep (ctx : Context) =
-    if not ctx.BreakLines then f (sep ctx) else
+let internal autoNlnCheck f sep (ctx : Context) =
+    if not ctx.BreakLines then false else
     // Create a dummy context to evaluate length of current operation
     use colWriter = new ColumnIndentedTextWriter(new StringWriter())
     let dummyCtx = ctx.With(colWriter)
     let col = (dummyCtx |> sep |> f).Writer.Column
     // This isn't accurate if we go to new lines
-    if col > ctx.Config.PageWidth then
+    col > ctx.Config.PageWidth
+
+/// Set a checkpoint to break at an appropriate column
+let internal autoNlnOrAddSep f sep (ctx : Context) =
+    let isNln = autoNlnCheck f sep ctx
+    if isNln then
        f (sepNln ctx)
     else
        f (sep ctx)

src/Fantomas/SourceTransformer.fs

@@ -307,4 +307,8 @@ let rec (|OneLinerLetOrUseL|_|) = function
 let rec (|MultilineLetOrUseL|_|) = function
     | (prefix, MultilineBinding x)::MultilineLetOrUseL(xs, ys) -> Some((prefix, x)::xs, ys)
     | (prefix, MultilineBinding x)::ys -> Some([prefix, x], ys)
-    | _ -> None
+    | _ -> None
+
+let addParenIfAutoNln synExpr f ctx =
+    let expr = f synExpr
+    ifElse (autoNlnCheck expr sepNone ctx && not (hasParenthesis synExpr)) (sepOpenT +> expr +> sepCloseT) expr ctx