Formatting original char from trivia. Fixes #632.

src/Fantomas.Tests/SynConstTests.fs

@@ -89,4 +89,15 @@ namespace SomeNamespace
 module SomeModule =
     let backspace = '\b'
     let formFeed = '\f'
+"""
+
+[<Test>]
+let ``escape unicode null, 632`` () =
+    formatSourceString false """let nulchar = '\u0000'
+let nullstr = "\u0000"
+"""  config
+    |> prepend newline
+    |> should equal """
+let nulchar = '\u0000'
+let nullstr = "\u0000"
 """

src/Fantomas.Tests/TokenParserTests.fs

@@ -396,3 +396,23 @@ let ``ident between tickets `` () =
     | [{ Item = IdentBetweenTicks("``/ operator combines paths``") }] ->
         pass()
     | _ -> fail()
+
+[<Test>]
+let ``simple char content`` () =
+    let source = "let someChar = \'s\'"
+    let (tokens,lineCount) = tokenize [] source
+    let trivia = getTriviaFromTokens tokens lineCount
+    match trivia with
+    | [{ Item = CharContent("\'s\'") }] ->
+        pass()
+    | _ -> fail()
+
+[<Test>]
+let ``escaped char content`` () =
+    let source = "let nulchar = \'\\u0000\'"
+    let (tokens,lineCount) = tokenize [] source
+    let trivia = getTriviaFromTokens tokens lineCount
+    match trivia with
+    | [{ Item = CharContent("\'\\u0000\'") }] ->
+        pass()
+    | _ -> fail()

src/Fantomas.Tests/TriviaTests.fs

@@ -42,7 +42,7 @@ let a = 9
         failwith "Expected line comment"
 
 [<Test>]
-let ``Line comment that is alone on the single, preceded by whitespaces`` () =
+let ``line comment that is alone on the single, preceded by whitespaces`` () =
     let source = """    // foo
 let a = 'c'
 """
@@ -52,7 +52,8 @@ let a = 'c'
         |> List.head
 
     match triviaNodes with
-    | [{ ContentBefore = [Comment(LineCommentOnSingleLine(lineComment))];  }] ->
+    | [{ ContentBefore = [Comment(LineCommentOnSingleLine(lineComment))];  }
+       { ContentItself = Some(CharContent("\'c\'")) }] ->
         lineComment == "// foo"
     | _ ->
         failwith "Expected line comment"
@@ -511,4 +512,17 @@ with empty lines"
     | [{ ContentItself = Some(StringContent(sc))
          Type = TriviaNodeType.MainNode("SynExpr.Const") }] ->
         sc == sprintf "\"\"\"%s\"\"\"" multilineString
+    | _ -> fail()
+
+[<Test>]
+let ``char content`` () =
+    let source = "let nulchar = \'\\u0000\'"
+    let trivia =
+        toTrivia source
+        |> List.head
+
+    match trivia with
+    | [{ ContentItself = Some(CharContent("\'\\u0000\'"))
+         Type = TriviaNodeType.MainNode("SynExpr.Const") }] ->
+        pass()
     | _ -> fail()

src/Fantomas/CodePrinter.fs

@@ -2292,8 +2292,15 @@ and genConst (c:SynConst) (r:range) =
                 !- (sprintf "\"%s\"" escaped)
             <| ctx
     | SynConst.Char(c) ->
-        let escapedChar = Char.escape c
-        !- (sprintf "\'%s\'" escapedChar)
+        fun (ctx: Context) ->
+            let charContentFromTrivia = TriviaHelpers.``get CharContent`` r ctx.Trivia
+            let expr =
+                match charContentFromTrivia with
+                | Some content -> !- content
+                | None ->
+                    let escapedChar = Char.escape c
+                    !- (sprintf "\'%s\'" escapedChar)
+            expr ctx
     | SynConst.Bytes(bytes,_) -> genConstBytes bytes r
     | SynConst.Measure(c, m) ->
         let measure =
@@ -2367,4 +2374,3 @@ and infixOperatorFromTrivia range fallback (ctx: Context) =
         | Some iiw -> !- iiw
         | None ->  !- fallback
     <| ctx
-

src/Fantomas/Context.fs

@@ -537,6 +537,7 @@ let internal printTriviaContent (c: TriviaContent) (ctx: Context) =
     | IdentOperatorAsWord _
     | IdentBetweenTicks _
     | NewlineAfter
+    | CharContent _
          -> sepNone // don't print here but somewhere in CodePrinter
     | Directive(s)
     | Comment(LineCommentOnSingleLine s) ->

src/Fantomas/TokenParser.fs

@@ -402,6 +402,13 @@ let rec private getTriviaFromTokensThemSelves (config: FormatConfig) (allTokens:
             |> List.prependItem foundTrivia
         getTriviaFromTokensThemSelves config allTokens rest info
 
+    | head::rest when (head.TokenInfo.TokenName = "CHAR") ->
+        let range = getRangeBetween head.TokenInfo.TokenName head head
+        let info =
+            Trivia.Create (CharContent(head.Content)) range
+            |> List.prependItem foundTrivia
+        getTriviaFromTokensThemSelves config allTokens rest info
+
     | (_)::rest -> getTriviaFromTokensThemSelves config allTokens rest foundTrivia
 
     | [] -> foundTrivia

src/Fantomas/Trivia.fs

@@ -310,6 +310,10 @@ let private addTriviaToTriviaNode (triviaNodes: TriviaNode list) trivia =
     | { Item = Number(_) as number; Range = range  } ->
         findNodeOnLineAndColumn triviaNodes range.StartLine range.StartColumn
         |> updateTriviaNode (fun tn -> { tn with ContentItself = Some number }) triviaNodes
+
+    | { Item = CharContent(_) as chNode; Range = range } ->
+        findNodeOnLineAndColumn triviaNodes range.StartLine range.StartColumn
+        |> updateTriviaNode (fun tn -> { tn with ContentItself = Some chNode }) triviaNodes
 
     | { Item = IdentOperatorAsWord(_) as ifw; Range = range } ->
         findBindingThatStartsWith triviaNodes range.StartColumn range.StartLine

src/Fantomas/TriviaHelpers.fs

@@ -4,31 +4,31 @@ open FSharp.Compiler.Range
 open Fantomas.TriviaTypes
 
 [<RequireQualifiedAccess>]
-module TriviaHelpers =
-    let internal findByRange (trivia: TriviaNode list) (range: range) =
+module internal TriviaHelpers =
+    let findByRange (trivia: TriviaNode list) (range: range) =
         trivia
         |> List.tryFind (fun t -> t.Range = range)
 
-    let internal findFirstContentBeforeByRange (trivia: TriviaNode list) (range: range) =
+    let findFirstContentBeforeByRange (trivia: TriviaNode list) (range: range) =
         findByRange trivia range
         |> Option.bind (fun t -> t.ContentBefore |> List.tryHead)
 
-    let internal ``has content after after that matches`` (findTrivia: TriviaNode -> bool) (contentAfter: TriviaContent -> bool) (trivia: TriviaNode list) =
+    let ``has content after after that matches`` (findTrivia: TriviaNode -> bool) (contentAfter: TriviaContent -> bool) (trivia: TriviaNode list) =
         List.tryFind findTrivia trivia
         |> Option.map (fun t -> t.ContentAfter |> List.exists contentAfter)
         |> Option.defaultValue false
 
-    let internal ``has content after that ends with`` (findTrivia: TriviaNode -> bool) (contentAfterEnd: TriviaContent -> bool) (trivia: TriviaNode list) =
+    let ``has content after that ends with`` (findTrivia: TriviaNode -> bool) (contentAfterEnd: TriviaContent -> bool) (trivia: TriviaNode list) =
         List.tryFind findTrivia trivia
         |> Option.bind (fun t -> t.ContentAfter |> List.tryLast |> Option.map contentAfterEnd)
         |> Option.defaultValue false
 
-    let internal ``is token of type`` tokenName (triviaNode: TriviaNode) =
+    let ``is token of type`` tokenName (triviaNode: TriviaNode) =
         match triviaNode.Type with
         | Token({ TokenInfo = ti }) -> ti.TokenName = tokenName
         | _ -> false
 
-    let internal ``keyword tokens inside range`` keywords range (trivia: TriviaNode list) =
+    let ``keyword tokens inside range`` keywords range (trivia: TriviaNode list) =
         trivia
         |> List.choose(fun t ->
             match t.Type with
@@ -38,7 +38,7 @@ module TriviaHelpers =
             | _ -> None
         )
 
-    let internal ``has line comment after`` triviaNode =
+    let ``has line comment after`` triviaNode =
         triviaNode.ContentAfter
         |> List.filter(fun tn ->
             match tn with
@@ -47,13 +47,21 @@ module TriviaHelpers =
         )
         |> (List.isEmpty >> not)
 
-    let internal ``has line comment before`` range triviaNodes =
+    let ``has line comment before`` range triviaNodes =
         triviaNodes
         |> List.tryFind (fun tv -> tv.Range = range)
         |> Option.map (fun tv -> tv.ContentBefore |> List.exists (function | Comment(LineCommentOnSingleLine(_)) -> true | _ -> false))
         |> Option.defaultValue false
 
-    let internal ``has content itself is ident between ticks`` range (triviaNodes: TriviaNode list) =
+    let ``get CharContent`` range triviaNodes =
+        triviaNodes
+        |> List.tryFind (fun tv -> tv.Range = range)
+        |> Option.bind (fun tv ->
+            match tv.ContentItself with
+            | Some(CharContent c) -> Some c
+            | _ -> None)
+
+    let ``has content itself is ident between ticks`` range (triviaNodes: TriviaNode list) =
         triviaNodes
         |> List.choose (fun tn ->
             match tn.Range = range, tn.ContentItself with

src/Fantomas/TriviaTypes.fs

@@ -36,6 +36,7 @@ type TriviaContent =
     | Newline
     | Directive of directive:string
     | NewlineAfter
+    | CharContent of string
 
 type Trivia =
     { Item: TriviaContent