Print trivia around SynConst and correct line comment construction. F…

…ixes #1518 (#1519)

src/Fantomas.Tests/SynConstTests.fs

@@ -308,3 +308,109 @@ let controlEscapes = "\a \b \f \v"
         """let hexEscape = "\x00"
 let controlEscapes = "\a \b \f \v"
 """
+
+[<Test>]
+let ``trivia after SynConst.Boolean, 1518`` () =
+    formatSourceString
+        false
+        """
+    match ast with
+    | ParsedInput.SigFile _input ->
+        // There is not much to explore in signature files
+        true
+    | ParsedInput.ImplFile input -> validateImplFileInput input
+
+    match t with
+    | TTuple _ -> not node.IsEmpty
+    | TFun _ -> true // Fun is grouped by brackets inside 'genType astContext true t'
+    | _ -> false
+
+    let condition e =
+        match e with
+        | ElIf _
+        | SynExpr.Lambda _ -> true
+        | _ -> false // "if .. then .. else" have precedence over ","
+
+    let x = 9
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+match ast with
+| ParsedInput.SigFile _input ->
+    // There is not much to explore in signature files
+    true
+| ParsedInput.ImplFile input -> validateImplFileInput input
+
+match t with
+| TTuple _ -> not node.IsEmpty
+| TFun _ -> true // Fun is grouped by brackets inside 'genType astContext true t'
+| _ -> false
+
+let condition e =
+    match e with
+    | ElIf _
+    | SynExpr.Lambda _ -> true
+    | _ -> false // "if .. then .. else" have precedence over ","
+
+let x = 9
+"""
+
+[<Test>]
+let ``trivia after SynConst.Char`` () =
+    formatSourceString
+        false
+        """
+let c = 'r' // meh
+let x = 1
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let c = 'r' // meh
+let x = 1
+"""
+
+[<Test>]
+let ``trivia after SynConst.Bytes`` () =
+    formatSourceString
+        false
+        """
+let bytes = "meh"B // meh
+let x = 1
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let bytes = "meh"B // meh
+let x = 1
+"""
+
+[<Test>]
+let ``trivia after SynConst.String, 1518`` () =
+    formatSourceString
+        false
+        "
+    let source = \"\"\"printfn foo
+
+printfn bar\"\"\" // difference is the 4 spaces on line 188
+
+    let x = 9
+"
+        config
+    |> prepend newline
+    |> should
+        equal
+        "
+let source = \"\"\"printfn foo
+
+printfn bar\"\"\" // difference is the 4 spaces on line 188
+
+let x = 9
+"

src/Fantomas/CodePrinter.fs

@@ -5173,7 +5173,9 @@ and genConst (c: SynConst) (r: Range) =
         +> !- ")"
         +> leaveNodeTokenByName r RPAREN
         |> genTriviaFor SynConst_Unit r
-    | SynConst.Bool (b) -> !-(if b then "true" else "false")
+    | SynConst.Bool (b) ->
+        !-(if b then "true" else "false")
+        |> genTriviaFor SynConst_Bool r
     | SynConst.Byte _
     | SynConst.SByte _
     | SynConst.Int16 _
@@ -5218,18 +5220,29 @@ and genConst (c: SynConst) (r: Range) =
             <| ctx
     | SynConst.Char (c) ->
         fun (ctx: Context) ->
-            let charContentFromTrivia =
-                TriviaHelpers.``get CharContent`` r ctx.TriviaMainNodes
+            let tn =
+                Map.tryFindOrEmptyList SynConst_Char ctx.TriviaMainNodes
+                |> List.tryFind (fun t -> RangeHelpers.rangeEq t.Range r)
 
             let expr =
-                match charContentFromTrivia with
-                | Some content -> !-content
+                match tn with
+                | Some ({ ContentItself = Some (CharContent (content)) } as tn) ->
+                    printContentBefore tn -- content
+                    +> printContentAfter tn
+                | Some tn ->
+                    let escapedChar = Char.escape c
+
+                    printContentBefore tn
+                    -- (sprintf "\'%s\'" escapedChar)
+                    +> printContentAfter tn
                 | None ->
                     let escapedChar = Char.escape c
                     !-(sprintf "\'%s\'" escapedChar)
 
             expr ctx
-    | SynConst.Bytes (bytes, r) -> genConstBytes bytes r
+    | SynConst.Bytes (bytes, r) ->
+        genConstBytes bytes r
+        |> genTriviaFor SynConst_Bytes r
     | SynConst.Measure (c, m) ->
         let measure =
             match m with

src/Fantomas/TokenParser.fs

@@ -41,20 +41,23 @@ let rec private tokenizeLine (tokenizer: FSharpLineTokenizer) sourceCodeLines st
         let extraToken =
             { TokenInfo = extraTokenInfo
               LineNumber = lineNumber
-              Content = getTokenText sourceCodeLines lineNumber extraTokenInfo }
+              Content = getTokenText sourceCodeLines lineNumber extraTokenInfo
+              Index = 0 }
 
         let token =
             { TokenInfo = tok
               LineNumber = lineNumber
-              Content = getTokenText sourceCodeLines lineNumber tok }
+              Content = getTokenText sourceCodeLines lineNumber tok
+              Index = 0 }
 
         tokenizeLine tokenizer sourceCodeLines state lineNumber (token :: extraToken :: tokens)
 
     | (Some tok, state), _ ->
         let token : Token =
             { TokenInfo = tok
               LineNumber = lineNumber
-              Content = getTokenText sourceCodeLines lineNumber tok }
+              Content = getTokenText sourceCodeLines lineNumber tok
+              Index = 0 }
         // Tokenize the rest, in the new state
         tokenizeLine tokenizer sourceCodeLines state lineNumber (token :: tokens)
 
@@ -83,6 +86,7 @@ let private createHashToken lineNumber content offset =
 
     { LineNumber = lineNumber
       Content = content
+      Index = 0
       TokenInfo =
           { TokenName = "HASH_IF"
             LeftColumn = left
@@ -337,6 +341,7 @@ and tokenize defines (hashTokens: Token list) (content: string) : Token list =
             tokens
 
     combined
+    |> List.mapi (fun idx t -> { t with Index = idx })
 
 let getDefinesWords (tokens: Token list) =
     tokens
@@ -672,54 +677,26 @@ let rec private getTriviaFromTokensThemSelves
     foundTrivia
     =
     match tokens with
-    | (NoCommentToken nct) :: WhiteSpaceToken _ :: (LineComments (commentTokens, nextTokens)) ->
-        let comment =
-            let commentText = collectComment commentTokens
-            let firstCommentToken = List.head commentTokens
-
-            (if nct.LineNumber < firstCommentToken.LineNumber then
-                 LineCommentOnSingleLine commentText
-             else
-                 LineCommentAfterSourceCode commentText)
-            |> Comment
-
-        let range =
-            let headToken = List.head commentTokens
-            let lastToken = List.tryLast commentTokens
-            getRangeBetween mkRange headToken (Option.defaultValue headToken lastToken)
-
-        let info =
-            Trivia.Create comment range
-            |> List.appendItem foundTrivia
-
-        getTriviaFromTokensThemSelves mkRange allTokens (nct :: nextTokens) info
-    | (NoCommentToken nct) :: (LineComments (commentTokens, nextTokens)) ->
-        let comment =
-            let commentText = collectComment commentTokens
-            let firstCommentToken = List.head commentTokens
-
-            (if nct.LineNumber < firstCommentToken.LineNumber
-                || (nct.TokenInfo.Tag = whiteSpaceTag
-                    && firstCommentToken.LineNumber = nct.LineNumber) then
-                 LineCommentOnSingleLine commentText
-             else
-                 LineCommentAfterSourceCode commentText)
-            |> Comment
-
-        let range =
-            let headToken = List.head commentTokens
-            let lastToken = List.tryLast commentTokens
-            getRangeBetween mkRange headToken (Option.defaultValue headToken lastToken)
-
-        let info =
-            Trivia.Create comment range
-            |> List.appendItem foundTrivia
+    | LineComments (({ Index = headIndex
+                       LineNumber = headLineNumber } :: _ as commentTokens),
+                    nextTokens) ->
+        let prevToken = List.tryItem (headIndex - 1) allTokens
+        let prevButOneToken = List.tryItem (headIndex - 2) allTokens
+
+        let commentType =
+            match prevButOneToken, prevToken with
+            | Some ({ LineNumber = ncln }), Some (WhiteSpaceToken _) ->
+                if ncln = headLineNumber then
+                    LineCommentAfterSourceCode
+                else
+                    LineCommentOnSingleLine
+            | Some ({ LineNumber = l1 }), Some ({ LineNumber = l2 }) when (headLineNumber = l1 && headLineNumber = l2) ->
+                LineCommentAfterSourceCode
+            | _ -> LineCommentOnSingleLine
 
-        getTriviaFromTokensThemSelves mkRange allTokens (nct :: nextTokens) info
-    | LineComments (commentTokens, nextTokens) ->
         let comment =
             collectComment commentTokens
-            |> LineCommentOnSingleLine
+            |> commentType
             |> Comment
 
         let range =

src/Fantomas/TriviaHelpers.fs

@@ -125,15 +125,5 @@ module internal TriviaHelpers =
                     | Some (StringContent sc) -> String.isMultiline sc
                     | _ -> false
 
-
                 RangeHelpers.rangeEq tn.Range range
                 && contentItSelfIsMultilineString ())
-
-    let ``get CharContent`` range (nodes: Map<FsAstType, TriviaNode list>) =
-        Map.tryFindOrEmptyList SynConst_Char nodes
-        |> List.tryFind (fun t -> RangeHelpers.rangeEq t.Range range)
-        |> Option.bind
-            (fun tv ->
-                match tv.ContentItself with
-                | Some (CharContent c) -> Some c
-                | _ -> None)

src/Fantomas/TriviaTypes.fs

@@ -56,7 +56,8 @@ type FsTokenType =
 type Token =
     { TokenInfo: FSharpTokenInfo
       LineNumber: int
-      Content: string }
+      Content: string
+      Index: int }
 
 type Comment =
     | LineCommentAfterSourceCode of comment: string