Use string interpolation instead of sprintf

src/Bolero.Server/RazorHost.fs

@@ -70,7 +70,7 @@ type RazorHostingExtensions =
     [<Extension>]
     static member RenderBoleroScript(html: IHtmlHelper, config: IBoleroHostConfig) =
         let k = if config.IsServer then "server" else "webassembly"
-        html.Raw(sprintf """<script src="_framework/blazor.%s.js"></script>""" k)
+        html.Raw($"""<script src="_framework/blazor.{k}.js"></script>""")
 
     [<Extension>]
     static member AddBoleroHost(this: IServiceCollection, ?server: bool, ?prerendered: bool, ?devToggle: bool) =

src/Bolero.Server/Remoting.fs

@@ -137,7 +137,7 @@ type internal ServerRemoteProvider(services: seq<RemotingService>) =
                 None
         )
         |> Option.defaultWith (fun () ->
-            failwithf "Remote service not registered: %s" typeof<'T>.FullName)
+            failwith $"Remote service not registered: {typeof<'T>.FullName}")
 
     interface IRemoteProvider with
 

src/Bolero.Templating.Provider/ConvertExpr.fs

@@ -59,7 +59,7 @@ let WrapExpr (innerType: Parsing.HoleType) (outerType: Parsing.HoleType) (expr:
         <@@ Node.Text ((%%expr: obj * Action<ChangeEventArgs>).Item1.ToString()) @@>
     | Parsing.AttributeValue, Parsing.DataBinding _ ->
         <@@ (%%expr: obj * Action<ChangeEventArgs>).Item1.ToString() @@>
-    | a, b -> failwithf "Hole name used multiple times with incompatible types (%A, %A)" a b
+    | a, b -> failwith $"Hole name used multiple times with incompatible types ({a}, {b})"
     |> Some
 
 /// Map an expression's vars from its parent, wrapping the expression in let declarations.
@@ -87,7 +87,7 @@ let rec ConvertAttrTextPart (vars: Map<string, Expr>) (text: Parsing.Expr) : Exp
     | Parsing.WrapVars (subst, text) ->
         WrapAndConvert vars subst ConvertAttrTextPart text
     | Parsing.Fst _ | Parsing.Snd _ | Parsing.Attr _ | Parsing.Elt _ ->
-        failwithf "Invalid text: %A" text
+        failwith $"Invalid text: {text}"
 
 let rec ConvertAttrValue (vars: Map<string, Expr>) (text: Parsing.Expr) : Expr<obj> =
     let box e = Expr.Coerce(e, typeof<obj>) |> Expr.Cast
@@ -106,7 +106,7 @@ let rec ConvertAttrValue (vars: Map<string, Expr>) (text: Parsing.Expr) : Expr<o
     | Parsing.WrapVars (subst, text) ->
         WrapAndConvert vars subst ConvertAttrValue text
     | Parsing.Attr _ | Parsing.Elt _ ->
-        failwithf "Invalid attr value: %A" text
+        failwith $"Invalid attr value: {text}"
 
 let rec ConvertAttr (vars: Map<string, Expr>) (attr: Parsing.Expr) : Expr<Attr> =
     match attr with
@@ -121,7 +121,7 @@ let rec ConvertAttr (vars: Map<string, Expr>) (attr: Parsing.Expr) : Expr<Attr>
     | Parsing.WrapVars (subst, attr) ->
         WrapAndConvert vars subst ConvertAttr attr
     | Parsing.Fst _ | Parsing.Snd _ | Parsing.PlainHtml _ | Parsing.Elt _ ->
-        failwithf "Invalid attribute: %A" attr
+        failwith $"Invalid attribute: {attr}"
 
 let rec ConvertNode (vars: Map<string, Expr>) (node: Parsing.Expr) : Expr<Node> =
     match node with
@@ -139,5 +139,5 @@ let rec ConvertNode (vars: Map<string, Expr>) (node: Parsing.Expr) : Expr<Node>
     | Parsing.WrapVars (subst, node) ->
         WrapAndConvert vars subst ConvertNode node
     | Parsing.Fst _ | Parsing.Snd _ | Parsing.Attr _ ->
-        failwithf "Invalid node: %A" node
+        failwith $"Invalid node: {node}"
 

src/Bolero.Templating.Provider/Parsing.fs

@@ -59,7 +59,7 @@ module HoleType =
         | Event _, Event _ -> Event typeof<EventArgs>
         | DataBinding valType, (String | Html | AttributeValue)
         | (String | Html | AttributeValue), DataBinding valType -> DataBinding valType
-        | _ -> failwithf "Hole name used multiple times with incompatible types: %s" holeName
+        | _ -> failwith $"Hole name used multiple times with incompatible types: {holeName}"
 
     /// Get the .NET type of the event handler argument for the given event name.
     let EventArg (name: string) : Type =
@@ -359,7 +359,7 @@ let ParseDoc (filename: option<string>) (doc: HtmlDocument) : ParsedTemplates =
         |> Seq.map (fun n ->
             match n.GetAttributeValue("id", null) with
             | null ->
-                failwithf "Nested template must have an id" // at %i:%i" n.Line n.LinePosition
+                failwith "Nested template must have an id" // at {n.Line}:{n.LinePosition}"
             | id ->
                 let parsed = ParseOneTemplate n.ChildNodes
                 n.Remove()

src/Bolero.Templating.Provider/Path.fs

@@ -35,7 +35,7 @@ let GetRelativePath (baseDir: string) (fullPath: string) =
         if thisDir = baseDir then
             fullPath.[thisDir.Length + 1..]
         elif thisDir.Length <= baseDir.Length then
-            invalidArg "fullPath" (sprintf "'%s' is not a subdirectory of '%s'" fullPath baseDir)
+            invalidArg "fullPath" $"'{fullPath}' is not a subdirectory of '{baseDir}'"
         else
             go (Path.GetDirectoryName thisDir)
     go fullPath

src/Bolero.Templating.Provider/Provider.fs

@@ -48,7 +48,7 @@ type Template (cfg: TypeProviderConfig) as this =
                 CodeGen.Populate ty pathOrHtml cfg.ResolutionFolder
                 asm.AddTypes([ty])
                 ty
-            | x -> failwithf "Unexpected parameter values: %A" x
+            | x -> failwith $"Unexpected parameter values: {x}"
         )
         templateTy.AddXmlDoc("\
             Provide content from a template HTML file.\n\
@@ -57,4 +57,4 @@ type Template (cfg: TypeProviderConfig) as this =
         with exn ->
             // Put the full error, including stack, in the message
             // so that it shows up in the compiler output.
-            failwithf "%A" exn
+            failwith $"{exn}"

src/Bolero/Remoting.fs

@@ -74,7 +74,7 @@ type RemotingExtensions =
     /// [omit]
     static member ExtractRemoteMethods(ty: Type) : Result<RemoteMethodDefinition[], list<string>> =
         if not (FSharpType.IsRecord ty) then
-            Error [sprintf "Remote type must be a record: %s" ty.FullName]
+            Error [$"Remote type must be a record: {ty.FullName}"]
         else
         let fields = FSharpType.GetRecordFields(ty, true)
         (fields, Ok [])

src/Bolero/Render.fs

@@ -38,35 +38,31 @@ type ElementReference = Microsoft.AspNetCore.Components.ElementReference
 type RenderTreeBuilder(b: BlazorTreeBuilder, indent: int, out: TextWriter) =
     let mutable indent = indent
 
-    let write fmt =
-            Printf.kprintf (fun s ->
-                out.Write(Array.create (indent * 2) ' ')
-                out.Write(s)
-                out.Flush()
-            ) fmt
-
-    let writen fmt =
-            Printf.kprintf (fun s ->
-                out.Write(Array.create (indent * 2) ' ')
-                out.WriteLine(s)
-                out.Flush()
-            ) fmt
+    let write (s: string) =
+        out.Write(Array.create (indent * 2) ' ')
+        out.Write(s)
+        out.Flush()
+
+    let writen (s: string) =
+        out.Write(Array.create (indent * 2) ' ')
+        out.WriteLine(s)
+        out.Flush()
 
     member this.AddContent(sequence: int, text: string) =
         if not (isNull b) then b.AddContent(sequence, text)
-        writen "Text %i %s" sequence text
+        writen $"Text {sequence} {text}"
 
     member this.AddContent(sequence: int, frag: RenderFragment) =
         if not (isNull b) then b.AddContent(sequence, frag.Frag)
-        write "Frag %i\n%s" sequence (frag.Show(indent + 1))
+        write $"Frag {sequence}\n{frag.Show(indent + 1)}"
 
     member this.AddMarkupContent(sequence: int, markup: string) =
         if not (isNull b) then b.AddMarkupContent(sequence, markup)
-        writen "Markup %i %s" sequence markup
+        writen $"Markup {sequence} {markup}"
 
     member this.OpenElement(sequence: int, name: string) =
         if not (isNull b) then b.OpenElement(sequence, name)
-        writen "OpenElt %i %s" sequence name
+        writen $"OpenElt {sequence} {name}"
         indent <- indent + 1
 
     member this.CloseElement() =
@@ -76,7 +72,7 @@ type RenderTreeBuilder(b: BlazorTreeBuilder, indent: int, out: TextWriter) =
 
     member this.OpenComponent(sequence: int, ty: Type) =
         if not (isNull b) then b.OpenComponent(sequence, ty)
-        writen "OpenComp %i %s" sequence ty.FullName
+        writen $"OpenComp {sequence} {ty.FullName}"
         indent <- indent + 1
 
     member this.CloseComponent() =
@@ -88,14 +84,14 @@ type RenderTreeBuilder(b: BlazorTreeBuilder, indent: int, out: TextWriter) =
         match value with
         | :? RenderFragment as f ->
             if not (isNull b) then b.AddAttribute(sequence, name, f.Frag)
-            writen "Attr %i %s\n%s" sequence name (f.Show(indent + 1))
+            writen $"Attr {sequence} {name}\n{f.Show(indent + 1)}"
         | value ->
             if not (isNull b) then b.AddAttribute(sequence, name, value)
-            writen "Attr %i %s %A" sequence name value
+            writen $"Attr {sequence} {name} {value}"
 
     member this.AddElementReferenceCapture(sequence: int, r: Action<ElementReference>) =
         b.AddElementReferenceCapture(sequence, r)
-        writen "ElementReference %i" sequence
+        writen $"ElementReference {sequence}"
 
 and RenderFragment(f: RenderTreeBuilder -> unit) =
     member this.Frag : BlazorFragment =

src/Bolero/Router.fs

@@ -109,28 +109,25 @@ type InvalidRouterKind =
 /// [category: Routing]
 exception InvalidRouter of kind: InvalidRouterKind with
     override this.Message =
-        let withCase (case: UnionCaseInfo) =
-            sprintf "Invalid router defined for union case %s.%s: %s"
-                case.DeclaringType.FullName case.Name
+        let withCase (case: UnionCaseInfo) s =
+            $"Invalid router defined for union case {case.DeclaringType.FullName}.{case.Name}: %s{s}"
         match this.kind with
         | InvalidRouterKind.UnsupportedType ty ->
             "Unsupported route type: " + ty.FullName
         | InvalidRouterKind.ParameterSyntax(case, field) ->
-            withCase case ("Invalid parameter syntax: " + field)
+            withCase case $"Invalid parameter syntax: {field}"
         | InvalidRouterKind.DuplicateField(case, field) ->
-            withCase case ("Field duplicated in the path: " + field)
+            withCase case $"Field duplicated in the path: {field}"
         | InvalidRouterKind.UnknownField(case, field) ->
-            withCase case ("Unknown field in the path: " + field)
+            withCase case $"Unknown field in the path: {field}"
         | InvalidRouterKind.MissingField(case, field) ->
-            withCase case ("Missing field in the path: " + field)
+            withCase case $"Missing field in the path: {field}"
         | InvalidRouterKind.ParameterTypeMismatch(case, field, otherCase, otherField) ->
-            withCase case (sprintf "Parameter %s at the same path position as %s's %s but has a different type"
-                field otherCase.Name otherField)
+            withCase case $"Parameter {field} at the same path position as {otherCase.Name}'s {otherField} but has a different type"
         | InvalidRouterKind.ModifierMismatch(case, field, otherCase, otherField) ->
-            withCase case (sprintf "Parameter %s at the same path position as %s's %s but has a different modifier"
-                field otherCase.Name otherField)
+            withCase case $"Parameter {field} at the same path position as {otherCase.Name}'s {otherField} but has a different modifier"
         | InvalidRouterKind.IdenticalPath(case, otherCase) ->
-            withCase case ("Matches the exact same path as " + otherCase.Name)
+            withCase case $"Matches the exact same path as {otherCase.Name}"
         | InvalidRouterKind.RestNotLast case ->
             withCase case "{*rest} parameter must be the last fragment"
         | InvalidRouterKind.InvalidRestType case ->

tests/Client/Main.fs

@@ -111,7 +111,7 @@ let update message model =
     | Submit -> { model with submitted = Some model.input }, []
     | RemoveItem k -> { model with items = Map.filter (fun k' _ -> k' <> k) model.items }, []
     | SetAddKey i -> { model with addKey = i }, []
-    | AddKey -> { model with items = Map.add model.addKey (sprintf "it's %i" model.addKey) model.items }, []
+    | AddKey -> { model with items = Map.add model.addKey $"it's {model.addKey}" model.items }, []
     | SetKeyOf k ->
         match Map.tryFind k model.items with
         | None -> model, []
@@ -151,7 +151,7 @@ let viewForm (js: IJSRuntime) model dispatch =
             )
             attr.style (if model.input = "" then "color:gray;" else null)
         ]
-        div [] [textf "selected radio item: %A" model.radioItem]
+        div [] [text $"selected radio item: {model.radioItem}"]
         forEach {1..10} <| fun ix ->
             input [
                 attr.``type`` "radio"
@@ -181,7 +181,7 @@ let viewForm (js: IJSRuntime) model dispatch =
                         SecretPw()
                             .Kind(b [] [text "secret"])
                             .Clear(fun _ -> dispatch (SetInput ""))
-                            .DblClick(fun e -> dispatch (SetInput (sprintf "(%f, %f)" e.ClientX e.ClientY)))
+                            .DblClick(fun e -> dispatch (SetInput $"({e.ClientX}, {e.ClientY})"))
                             .Input(model.input, fun s -> dispatch (SetInput s))
                             .Value(model.addKey, fun k -> dispatch (SetAddKey k))
                             .Elt()
@@ -236,22 +236,22 @@ type ViewItemPage() =
             p [] [
                 text "Model: "
                 button [on.click (fun _ -> dispatch (SetPage (Item (k, { Model = m - 1 }))))] [text "-"]
-                textf "%i" m
+                text $"{m}"
                 button [on.click (fun _ -> dispatch (SetPage (Item (k, { Model = m + 1 }))))] [text "+"]
             ]
         ]
 
 let viewLazy model dispatch =
-    let lazyViewFunction = (fun m -> text (sprintf "Lazy values: (%i,%s), re-render random number check: %i" m.value m.nonEqVal (System.Random().Next())))
+    let lazyViewFunction = (fun m -> text $"Lazy values: ({m.value},{m.nonEqVal}), re-render random number check: {System.Random().Next()}")
     div [] [
         pre [] [
             text """
 let viewLazy model dispatch =
     div [] [
         p [] [button [on.click (fun _ -> dispatch IncNonLazyVal)] [text "Increase non-lazy value"]]
         p [] [button [on.click (fun _ -> dispatch IncLazyVal)] [text "Increase lazy value"]]
-        p [] [text (sprintf "Non-lazy value: %i, re-render random number check: %i" model.nonLazyValue (System.Random().Next()))]
-        p [] [lazyComp (fun m -> text (sprintf "Lazy value: %i, re-render random number check: %i" m.value (System.Random().Next()))) model.lazyModel]
+        p [] [text $"Non-lazy value: {model.nonLazyValue}, re-render random number check: {System.Random().Next()}"]
+        p [] [lazyComp (fun m -> text $"Lazy values: ({m.value},{m.nonEqVal}), re-render random number check: {System.Random().Next()}") model.lazyModel]
     ]
             """
         ]
@@ -263,7 +263,7 @@ let viewLazy model dispatch =
                 on.change (fun e -> e.Value |> string |> SetLazyNonEqVal |> dispatch)
             ]
         ]
-        p [] [text (sprintf "Non-lazy value: %i, re-render random number check: %i" model.nonLazyValue (System.Random().Next()))]
+        p [] [text $"Non-lazy value: {model.nonLazyValue}, re-render random number check: {System.Random().Next()}"]
         p [] [lazyComp lazyViewFunction model.lazyModel]
         p [] [lazyCompWith (fun m1 m2 -> m1.value = m2.value) lazyViewFunction model.lazyModel]
         p [] [lazyCompBy (fun m -> (m.value, m.value2)) lazyViewFunction model.lazyModel]
@@ -295,5 +295,5 @@ type MyApp() =
     override this.Program =
         Program.mkProgram (fun _ -> initModel(), []) update (view this.JSRuntime)
         //|> Program.withConsoleTrace
-        |> Program.withErrorHandler (fun (msg, exn) -> printfn "%s: %A" msg exn)
+        |> Program.withErrorHandler (fun (msg, exn) -> printfn $"{msg}: {exn}")
         |> Program.withRouter router

tests/Remoting.Client/Main.fs

@@ -141,7 +141,7 @@ let router : Router<Page, Model, Message> =
         getEndPoint = fun m -> m.page
         getRoute = function
             | Home -> "/"
-            | Custom i -> sprintf "/custom/%i" i
+            | Custom i -> $"/custom/{i}"
         setRoute = fun s ->
             match s.Trim('/').Split('/') with
             | [|""|] -> Some (SetPage Home)
@@ -189,7 +189,7 @@ let Display model dispatch =
             ]
         | Some login ->
             concat [
-                textf "Logged in as %s" login
+                text "Logged in as {login}"
                 button [on.click (fun _ -> dispatch Logout)] [text "Log out"]
             ]
         hr []
@@ -210,7 +210,7 @@ let Display model dispatch =
             comp<AuthorizeView> [
                 attr.fragmentWith "Authorized" <| fun (context: AuthenticationState) ->
                     printfn "Rendering Authorized"
-                    div [] [textf "You're authorized! Welcome %s" context.User.Identity.Name]
+                    div [] [text $"You're authorized! Welcome {context.User.Identity.Name}"]
                 attr.fragmentWith "NotAuthorized" <| fun (_: AuthenticationState) ->
                     printfn "Rendering NotAuthorized"
                     div [] [text "You're not authorized :("]

tests/Server/Properties/launchSettings.json

@@ -3,8 +3,8 @@
     "windowsAuthentication": false,
     "anonymousAuthentication": true,
     "iisExpress": {
-      "applicationUrl": "http://localhost:52982/",
-      "sslPort": 0
+      "applicationUrl": "http://localhost:54002/",
+      "sslPort": 44338
     }
   },
   "profiles": {

tests/Unit.Client/Elmish.fs

@@ -61,7 +61,7 @@ type IntInput() =
                 attr.value model
                 on.input (fun e -> dispatch (int (e.Value :?> string)))
             ]
-            span [attr.classes ["intValue-repeat"]] [textf "%i" model]
+            span [attr.classes ["intValue-repeat"]] [text $"{model}"]
         ]
 
 let view model dispatch =