Extract some utilities from http-client branch (#260)

ConsumePlugin/Args.fs

@@ -204,6 +204,30 @@ type FlagsIntoPositionalArgs =
         GrabEverything : string list
     }
 
+[<ArgParser true>]
+type FlagsIntoPositionalArgsChoice =
+    {
+        A : string
+        [<PositionalArgs true>]
+        GrabEverything : Choice<string, string> list
+    }
+
+[<ArgParser true>]
+type FlagsIntoPositionalArgsInt =
+    {
+        A : string
+        [<PositionalArgs true>]
+        GrabEverything : int list
+    }
+
+[<ArgParser true>]
+type FlagsIntoPositionalArgsIntChoice =
+    {
+        A : string
+        [<PositionalArgs true>]
+        GrabEverything : Choice<int, int> list
+    }
+
 [<ArgParser true>]
 type FlagsIntoPositionalArgs' =
     {

ConsumePlugin/GeneratedArgs.fs

@@ -3635,6 +3635,9 @@ module FlagsIntoPositionalArgsArgParse =
                         | Error exc ->
                             if setFlagValue key then
                                 go ParseState_FlagsIntoPositionalArgs.AwaitingKey (arg :: args)
+                            else if true then
+                                key |> (fun x -> x) |> arg_1.Add
+                                go ParseState_FlagsIntoPositionalArgs.AwaitingKey (arg :: args)
                             else
                                 match exc with
                                 | None ->
@@ -3672,6 +3675,498 @@ open System
 open System.IO
 open WoofWare.Myriad.Plugins
 
+/// Methods to parse arguments for the type FlagsIntoPositionalArgsChoice
+[<AutoOpen>]
+module FlagsIntoPositionalArgsChoiceArgParse =
+    type private ParseState_FlagsIntoPositionalArgsChoice =
+        /// Ready to consume a key or positional arg
+        | AwaitingKey
+        /// Waiting to receive a value for the key we've already consumed
+        | AwaitingValue of key : string
+
+    /// Extension methods for argument parsing
+    type FlagsIntoPositionalArgsChoice with
+
+        static member parse'
+            (getEnvironmentVariable : string -> string)
+            (args : string list)
+            : FlagsIntoPositionalArgsChoice
+            =
+            let ArgParser_errors = ResizeArray ()
+
+            let helpText () =
+                [
+                    (sprintf "%s  string%s%s" (sprintf "--%s" "a") "" "")
+                    (sprintf
+                        "%s  string%s%s"
+                        (sprintf "--%s" "grab-everything")
+                        " (positional args) (can be repeated)"
+                        "")
+                ]
+                |> String.concat "\n"
+
+            let arg_1 : Choice<string, string> ResizeArray = ResizeArray ()
+            let mutable arg_0 : string option = None
+
+            /// Processes the key-value pair, returning Error if no key was matched.
+            /// If the key is an arg which can have arity 1, but throws when consuming that arg, we return Error(<the message>).
+            /// This can nevertheless be a successful parse, e.g. when the key may have arity 0.
+            let processKeyValue (key : string) (value : string) : Result<unit, string option> =
+                if System.String.Equals (key, sprintf "--%s" "a", System.StringComparison.OrdinalIgnoreCase) then
+                    match arg_0 with
+                    | Some x ->
+                        sprintf
+                            "Argument '%s' was supplied multiple times: %s and %s"
+                            (sprintf "--%s" "a")
+                            (x.ToString ())
+                            (value.ToString ())
+                        |> ArgParser_errors.Add
+
+                        Ok ()
+                    | None ->
+                        try
+                            arg_0 <- value |> (fun x -> x) |> Some
+                            Ok ()
+                        with _ as exc ->
+                            exc.Message |> Some |> Error
+                else if
+                    System.String.Equals (
+                        key,
+                        sprintf "--%s" "grab-everything",
+                        System.StringComparison.OrdinalIgnoreCase
+                    )
+                then
+                    value |> (fun x -> x) |> Choice1Of2 |> arg_1.Add
+                    () |> Ok
+                else
+                    Error None
+
+            /// Returns false if we didn't set a value.
+            let setFlagValue (key : string) : bool = false
+
+            let rec go (state : ParseState_FlagsIntoPositionalArgsChoice) (args : string list) =
+                match args with
+                | [] ->
+                    match state with
+                    | ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey -> ()
+                    | ParseState_FlagsIntoPositionalArgsChoice.AwaitingValue key ->
+                        if setFlagValue key then
+                            ()
+                        else
+                            sprintf
+                                "Trailing argument %s had no value. Use a double-dash to separate positional args from key-value args."
+                                key
+                            |> ArgParser_errors.Add
+                | "--" :: rest -> arg_1.AddRange (rest |> Seq.map (fun x -> x) |> Seq.map Choice2Of2)
+                | arg :: args ->
+                    match state with
+                    | ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey ->
+                        if arg.StartsWith ("--", System.StringComparison.Ordinal) then
+                            if arg = "--help" then
+                                helpText () |> failwithf "Help text requested.\n%s"
+                            else
+                                let equals = arg.IndexOf (char 61)
+
+                                if equals < 0 then
+                                    args |> go (ParseState_FlagsIntoPositionalArgsChoice.AwaitingValue arg)
+                                else
+                                    let key = arg.[0 .. equals - 1]
+                                    let value = arg.[equals + 1 ..]
+
+                                    match processKeyValue key value with
+                                    | Ok () -> go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey args
+                                    | Error x ->
+                                        if true then
+                                            arg |> (fun x -> x) |> Choice1Of2 |> arg_1.Add
+                                            go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey args
+                                        else
+                                            match x with
+                                            | None ->
+                                                failwithf
+                                                    "Unable to process argument %s as key %s and value %s"
+                                                    arg
+                                                    key
+                                                    value
+                                            | Some msg ->
+                                                sprintf "%s (at arg %s)" msg arg |> ArgParser_errors.Add
+                                                go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey args
+                        else
+                            arg |> (fun x -> x) |> Choice1Of2 |> arg_1.Add
+                            go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey args
+                    | ParseState_FlagsIntoPositionalArgsChoice.AwaitingValue key ->
+                        match processKeyValue key arg with
+                        | Ok () -> go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey args
+                        | Error exc ->
+                            if setFlagValue key then
+                                go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey (arg :: args)
+                            else if true then
+                                key |> (fun x -> x) |> Choice1Of2 |> arg_1.Add
+                                go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey (arg :: args)
+                            else
+                                match exc with
+                                | None ->
+                                    failwithf
+                                        "Unable to process supplied arg %s. Help text follows.\n%s"
+                                        key
+                                        (helpText ())
+                                | Some msg -> msg |> ArgParser_errors.Add
+
+            go ParseState_FlagsIntoPositionalArgsChoice.AwaitingKey args
+            let arg_1 = arg_1 |> Seq.toList
+
+            let arg_0 =
+                match arg_0 with
+                | None ->
+                    sprintf "Required argument '%s' received no value" (sprintf "--%s" "a")
+                    |> ArgParser_errors.Add
+
+                    Unchecked.defaultof<_>
+                | Some x -> x
+
+            if 0 = ArgParser_errors.Count then
+                {
+                    A = arg_0
+                    GrabEverything = arg_1
+                }
+            else
+                ArgParser_errors |> String.concat "\n" |> failwithf "Errors during parse!\n%s"
+
+        static member parse (args : string list) : FlagsIntoPositionalArgsChoice =
+            FlagsIntoPositionalArgsChoice.parse' System.Environment.GetEnvironmentVariable args
+namespace ConsumePlugin
+
+open System
+open System.IO
+open WoofWare.Myriad.Plugins
+
+/// Methods to parse arguments for the type FlagsIntoPositionalArgsInt
+[<AutoOpen>]
+module FlagsIntoPositionalArgsIntArgParse =
+    type private ParseState_FlagsIntoPositionalArgsInt =
+        /// Ready to consume a key or positional arg
+        | AwaitingKey
+        /// Waiting to receive a value for the key we've already consumed
+        | AwaitingValue of key : string
+
+    /// Extension methods for argument parsing
+    type FlagsIntoPositionalArgsInt with
+
+        static member parse'
+            (getEnvironmentVariable : string -> string)
+            (args : string list)
+            : FlagsIntoPositionalArgsInt
+            =
+            let ArgParser_errors = ResizeArray ()
+
+            let helpText () =
+                [
+                    (sprintf "%s  string%s%s" (sprintf "--%s" "a") "" "")
+                    (sprintf
+                        "%s  int32%s%s"
+                        (sprintf "--%s" "grab-everything")
+                        " (positional args) (can be repeated)"
+                        "")
+                ]
+                |> String.concat "\n"
+
+            let arg_1 : int ResizeArray = ResizeArray ()
+            let mutable arg_0 : string option = None
+
+            /// Processes the key-value pair, returning Error if no key was matched.
+            /// If the key is an arg which can have arity 1, but throws when consuming that arg, we return Error(<the message>).
+            /// This can nevertheless be a successful parse, e.g. when the key may have arity 0.
+            let processKeyValue (key : string) (value : string) : Result<unit, string option> =
+                if System.String.Equals (key, sprintf "--%s" "a", System.StringComparison.OrdinalIgnoreCase) then
+                    match arg_0 with
+                    | Some x ->
+                        sprintf
+                            "Argument '%s' was supplied multiple times: %s and %s"
+                            (sprintf "--%s" "a")
+                            (x.ToString ())
+                            (value.ToString ())
+                        |> ArgParser_errors.Add
+
+                        Ok ()
+                    | None ->
+                        try
+                            arg_0 <- value |> (fun x -> x) |> Some
+                            Ok ()
+                        with _ as exc ->
+                            exc.Message |> Some |> Error
+                else if
+                    System.String.Equals (
+                        key,
+                        sprintf "--%s" "grab-everything",
+                        System.StringComparison.OrdinalIgnoreCase
+                    )
+                then
+                    value |> (fun x -> System.Int32.Parse x) |> arg_1.Add
+                    () |> Ok
+                else
+                    Error None
+
+            /// Returns false if we didn't set a value.
+            let setFlagValue (key : string) : bool = false
+
+            let rec go (state : ParseState_FlagsIntoPositionalArgsInt) (args : string list) =
+                match args with
+                | [] ->
+                    match state with
+                    | ParseState_FlagsIntoPositionalArgsInt.AwaitingKey -> ()
+                    | ParseState_FlagsIntoPositionalArgsInt.AwaitingValue key ->
+                        if setFlagValue key then
+                            ()
+                        else
+                            sprintf
+                                "Trailing argument %s had no value. Use a double-dash to separate positional args from key-value args."
+                                key
+                            |> ArgParser_errors.Add
+                | "--" :: rest -> arg_1.AddRange (rest |> Seq.map (fun x -> System.Int32.Parse x))
+                | arg :: args ->
+                    match state with
+                    | ParseState_FlagsIntoPositionalArgsInt.AwaitingKey ->
+                        if arg.StartsWith ("--", System.StringComparison.Ordinal) then
+                            if arg = "--help" then
+                                helpText () |> failwithf "Help text requested.\n%s"
+                            else
+                                let equals = arg.IndexOf (char 61)
+
+                                if equals < 0 then
+                                    args |> go (ParseState_FlagsIntoPositionalArgsInt.AwaitingValue arg)
+                                else
+                                    let key = arg.[0 .. equals - 1]
+                                    let value = arg.[equals + 1 ..]
+
+                                    match processKeyValue key value with
+                                    | Ok () -> go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey args
+                                    | Error x ->
+                                        if true then
+                                            arg |> (fun x -> System.Int32.Parse x) |> arg_1.Add
+                                            go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey args
+                                        else
+                                            match x with
+                                            | None ->
+                                                failwithf
+                                                    "Unable to process argument %s as key %s and value %s"
+                                                    arg
+                                                    key
+                                                    value
+                                            | Some msg ->
+                                                sprintf "%s (at arg %s)" msg arg |> ArgParser_errors.Add
+                                                go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey args
+                        else
+                            arg |> (fun x -> System.Int32.Parse x) |> arg_1.Add
+                            go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey args
+                    | ParseState_FlagsIntoPositionalArgsInt.AwaitingValue key ->
+                        match processKeyValue key arg with
+                        | Ok () -> go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey args
+                        | Error exc ->
+                            if setFlagValue key then
+                                go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey (arg :: args)
+                            else if true then
+                                key |> (fun x -> System.Int32.Parse x) |> arg_1.Add
+                                go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey (arg :: args)
+                            else
+                                match exc with
+                                | None ->
+                                    failwithf
+                                        "Unable to process supplied arg %s. Help text follows.\n%s"
+                                        key
+                                        (helpText ())
+                                | Some msg -> msg |> ArgParser_errors.Add
+
+            go ParseState_FlagsIntoPositionalArgsInt.AwaitingKey args
+            let arg_1 = arg_1 |> Seq.toList
+
+            let arg_0 =
+                match arg_0 with
+                | None ->
+                    sprintf "Required argument '%s' received no value" (sprintf "--%s" "a")
+                    |> ArgParser_errors.Add
+
+                    Unchecked.defaultof<_>
+                | Some x -> x
+
+            if 0 = ArgParser_errors.Count then
+                {
+                    A = arg_0
+                    GrabEverything = arg_1
+                }
+            else
+                ArgParser_errors |> String.concat "\n" |> failwithf "Errors during parse!\n%s"
+
+        static member parse (args : string list) : FlagsIntoPositionalArgsInt =
+            FlagsIntoPositionalArgsInt.parse' System.Environment.GetEnvironmentVariable args
+namespace ConsumePlugin
+
+open System
+open System.IO
+open WoofWare.Myriad.Plugins
+
+/// Methods to parse arguments for the type FlagsIntoPositionalArgsIntChoice
+[<AutoOpen>]
+module FlagsIntoPositionalArgsIntChoiceArgParse =
+    type private ParseState_FlagsIntoPositionalArgsIntChoice =
+        /// Ready to consume a key or positional arg
+        | AwaitingKey
+        /// Waiting to receive a value for the key we've already consumed
+        | AwaitingValue of key : string
+
+    /// Extension methods for argument parsing
+    type FlagsIntoPositionalArgsIntChoice with
+
+        static member parse'
+            (getEnvironmentVariable : string -> string)
+            (args : string list)
+            : FlagsIntoPositionalArgsIntChoice
+            =
+            let ArgParser_errors = ResizeArray ()
+
+            let helpText () =
+                [
+                    (sprintf "%s  string%s%s" (sprintf "--%s" "a") "" "")
+                    (sprintf
+                        "%s  int32%s%s"
+                        (sprintf "--%s" "grab-everything")
+                        " (positional args) (can be repeated)"
+                        "")
+                ]
+                |> String.concat "\n"
+
+            let arg_1 : Choice<int, int> ResizeArray = ResizeArray ()
+            let mutable arg_0 : string option = None
+
+            /// Processes the key-value pair, returning Error if no key was matched.
+            /// If the key is an arg which can have arity 1, but throws when consuming that arg, we return Error(<the message>).
+            /// This can nevertheless be a successful parse, e.g. when the key may have arity 0.
+            let processKeyValue (key : string) (value : string) : Result<unit, string option> =
+                if System.String.Equals (key, sprintf "--%s" "a", System.StringComparison.OrdinalIgnoreCase) then
+                    match arg_0 with
+                    | Some x ->
+                        sprintf
+                            "Argument '%s' was supplied multiple times: %s and %s"
+                            (sprintf "--%s" "a")
+                            (x.ToString ())
+                            (value.ToString ())
+                        |> ArgParser_errors.Add
+
+                        Ok ()
+                    | None ->
+                        try
+                            arg_0 <- value |> (fun x -> x) |> Some
+                            Ok ()
+                        with _ as exc ->
+                            exc.Message |> Some |> Error
+                else if
+                    System.String.Equals (
+                        key,
+                        sprintf "--%s" "grab-everything",
+                        System.StringComparison.OrdinalIgnoreCase
+                    )
+                then
+                    value |> (fun x -> System.Int32.Parse x) |> Choice1Of2 |> arg_1.Add
+                    () |> Ok
+                else
+                    Error None
+
+            /// Returns false if we didn't set a value.
+            let setFlagValue (key : string) : bool = false
+
+            let rec go (state : ParseState_FlagsIntoPositionalArgsIntChoice) (args : string list) =
+                match args with
+                | [] ->
+                    match state with
+                    | ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey -> ()
+                    | ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingValue key ->
+                        if setFlagValue key then
+                            ()
+                        else
+                            sprintf
+                                "Trailing argument %s had no value. Use a double-dash to separate positional args from key-value args."
+                                key
+                            |> ArgParser_errors.Add
+                | "--" :: rest -> arg_1.AddRange (rest |> Seq.map (fun x -> System.Int32.Parse x) |> Seq.map Choice2Of2)
+                | arg :: args ->
+                    match state with
+                    | ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey ->
+                        if arg.StartsWith ("--", System.StringComparison.Ordinal) then
+                            if arg = "--help" then
+                                helpText () |> failwithf "Help text requested.\n%s"
+                            else
+                                let equals = arg.IndexOf (char 61)
+
+                                if equals < 0 then
+                                    args |> go (ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingValue arg)
+                                else
+                                    let key = arg.[0 .. equals - 1]
+                                    let value = arg.[equals + 1 ..]
+
+                                    match processKeyValue key value with
+                                    | Ok () -> go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey args
+                                    | Error x ->
+                                        if true then
+                                            arg |> (fun x -> System.Int32.Parse x) |> Choice1Of2 |> arg_1.Add
+                                            go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey args
+                                        else
+                                            match x with
+                                            | None ->
+                                                failwithf
+                                                    "Unable to process argument %s as key %s and value %s"
+                                                    arg
+                                                    key
+                                                    value
+                                            | Some msg ->
+                                                sprintf "%s (at arg %s)" msg arg |> ArgParser_errors.Add
+                                                go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey args
+                        else
+                            arg |> (fun x -> System.Int32.Parse x) |> Choice1Of2 |> arg_1.Add
+                            go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey args
+                    | ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingValue key ->
+                        match processKeyValue key arg with
+                        | Ok () -> go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey args
+                        | Error exc ->
+                            if setFlagValue key then
+                                go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey (arg :: args)
+                            else if true then
+                                key |> (fun x -> System.Int32.Parse x) |> Choice1Of2 |> arg_1.Add
+                                go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey (arg :: args)
+                            else
+                                match exc with
+                                | None ->
+                                    failwithf
+                                        "Unable to process supplied arg %s. Help text follows.\n%s"
+                                        key
+                                        (helpText ())
+                                | Some msg -> msg |> ArgParser_errors.Add
+
+            go ParseState_FlagsIntoPositionalArgsIntChoice.AwaitingKey args
+            let arg_1 = arg_1 |> Seq.toList
+
+            let arg_0 =
+                match arg_0 with
+                | None ->
+                    sprintf "Required argument '%s' received no value" (sprintf "--%s" "a")
+                    |> ArgParser_errors.Add
+
+                    Unchecked.defaultof<_>
+                | Some x -> x
+
+            if 0 = ArgParser_errors.Count then
+                {
+                    A = arg_0
+                    GrabEverything = arg_1
+                }
+            else
+                ArgParser_errors |> String.concat "\n" |> failwithf "Errors during parse!\n%s"
+
+        static member parse (args : string list) : FlagsIntoPositionalArgsIntChoice =
+            FlagsIntoPositionalArgsIntChoice.parse' System.Environment.GetEnvironmentVariable args
+namespace ConsumePlugin
+
+open System
+open System.IO
+open WoofWare.Myriad.Plugins
+
 /// Methods to parse arguments for the type FlagsIntoPositionalArgs'
 [<AutoOpen>]
 module FlagsIntoPositionalArgs'ArgParse =
@@ -3796,6 +4291,9 @@ module FlagsIntoPositionalArgs'ArgParse =
                         | Error exc ->
                             if setFlagValue key then
                                 go ParseState_FlagsIntoPositionalArgs'.AwaitingKey (arg :: args)
+                            else if false then
+                                key |> (fun x -> x) |> arg_1.Add
+                                go ParseState_FlagsIntoPositionalArgs'.AwaitingKey (arg :: args)
                             else
                                 match exc with
                                 | None ->

WoofWare.Myriad.Plugins.Test/TestArgParser/TestArgParser.fs

@@ -623,30 +623,71 @@ Required argument '--exact' received no value"""
     let ``Can collect *all* non-help args into positional args with includeFlagLike`` () =
         let getEnvVar (_ : string) = failwith "do not call"
 
-        FlagsIntoPositionalArgs.parse' getEnvVar [ "--a" ; "foo" ; "--b=false" ; "--c=hi" ; "--" ; "--help" ]
+        FlagsIntoPositionalArgs.parse' getEnvVar [ "--a" ; "foo" ; "--b=false" ; "--c" ; "hi" ; "--" ; "--help" ]
         |> shouldEqual
             {
                 A = "foo"
-                GrabEverything = [ "--b=false" ; "--c=hi" ; "--help" ]
+                GrabEverything = [ "--b=false" ; "--c" ; "hi" ; "--help" ]
             }
 
         // Users might consider this eccentric!
         // But we're only a simple arg parser; we don't look around to see whether this is "almost"
         // a valid parse.
-        FlagsIntoPositionalArgs.parse' getEnvVar [ "--a" ; "--b=false" ; "--c=hi" ; "--" ; "--help" ]
+        FlagsIntoPositionalArgs.parse' getEnvVar [ "--a" ; "--b=false" ; "--c" ; "hi" ; "--" ; "--help" ]
         |> shouldEqual
             {
                 A = "--b=false"
-                GrabEverything = [ "--c=hi" ; "--help" ]
+                GrabEverything = [ "--c" ; "hi" ; "--help" ]
             }
 
     [<Test>]
-    let ``Can refuse to collect non-help args`` () =
+    let ``Can collect non-help args into positional args with Choice`` () =
+        let getEnvVar (_ : string) = failwith "do not call"
+
+        FlagsIntoPositionalArgsChoice.parse' getEnvVar [ "--a" ; "foo" ; "--b=false" ; "--c" ; "hi" ; "--" ; "--help" ]
+        |> shouldEqual
+            {
+                A = "foo"
+                GrabEverything =
+                    [
+                        Choice1Of2 "--b=false"
+                        Choice1Of2 "--c"
+                        Choice1Of2 "hi"
+                        Choice2Of2 "--help"
+                    ]
+            }
+
+    [<Test>]
+    let ``Can collect non-help args into positional args, and we parse on the way`` () =
+        let getEnvVar (_ : string) = failwith "do not call"
+
+        FlagsIntoPositionalArgsInt.parse' getEnvVar [ "3" ; "--a" ; "foo" ; "5" ; "--" ; "98" ]
+        |> shouldEqual
+            {
+                A = "foo"
+                GrabEverything = [ 3 ; 5 ; 98 ]
+            }
+
+    [<Test>]
+    let ``Can collect non-help args into positional args with Choice, and we parse on the way`` () =
+        let getEnvVar (_ : string) = failwith "do not call"
+
+        FlagsIntoPositionalArgsIntChoice.parse' getEnvVar [ "3" ; "--a" ; "foo" ; "5" ; "--" ; "98" ]
+        |> shouldEqual
+            {
+                A = "foo"
+                GrabEverything = [ Choice1Of2 3 ; Choice1Of2 5 ; Choice2Of2 98 ]
+            }
+
+    [<Test>]
+    let ``Can refuse to collect non-help args with PositionalArgs false`` () =
         let getEnvVar (_ : string) = failwith "do not call"
 
         let exc =
             Assert.Throws<exn> (fun () ->
-                FlagsIntoPositionalArgs'.parse' getEnvVar [ "--a" ; "foo" ; "--b=false" ; "--c=hi" ; "--" ; "--help" ]
+                FlagsIntoPositionalArgs'.parse'
+                    getEnvVar
+                    [ "--a" ; "foo" ; "--b=false" ; "--c" ; "hi" ; "--" ; "--help" ]
                 |> ignore<FlagsIntoPositionalArgs'>
             )
 

WoofWare.Myriad.Plugins/ArgParserGenerator.fs

@@ -1019,12 +1019,12 @@ module internal ArgParserGenerator =
                     recurseKey
                 ]
 
-        let notMatched =
-            let posAttr =
-                match leftoverArgAcc with
-                | ChoicePositional.Choice a
-                | ChoicePositional.Normal a -> a
+        let posAttr =
+            match leftoverArgAcc with
+            | ChoicePositional.Choice a
+            | ChoicePositional.Normal a -> a
 
+        let notMatched =
             let handleFailure =
                 [
                     SynMatchClause.create (SynPat.named "None") fail
@@ -1113,6 +1113,8 @@ module internal ArgParserGenerator =
         let processValue =
             // During failure, we've received an optional exception message that happened when we tried to parse
             // the value; it's in the variable `exc`.
+            // `fail` is for the case where we're genuinely emitting an error.
+            // If we're in `PositionalArgs true` mode, though, we won't call `fail`.
             let fail =
                 [
                     SynExpr.createIdent "failwithf"
@@ -1132,6 +1134,27 @@ module internal ArgParserGenerator =
                 ]
                 |> SynExpr.createMatch (SynExpr.createIdent "exc")
 
+            let onFailure =
+                match posAttr with
+                | None -> fail
+                | Some includeFlagLike ->
+                    [
+                        SynExpr.createIdent "key"
+                        |> SynExpr.pipeThroughFunction leftoverArgParser
+                        |> fun i ->
+                            match leftoverArgAcc with
+                            | ChoicePositional.Choice _ ->
+                                i |> SynExpr.pipeThroughFunction (SynExpr.createIdent "Choice1Of2")
+                            | ChoicePositional.Normal _ -> i
+                        |> SynExpr.pipeThroughFunction (SynExpr.createLongIdent' [ leftoverArgs ; Ident.create "Add" ])
+
+                        SynExpr.createIdent "go"
+                        |> SynExpr.applyTo (SynExpr.createLongIdent' [ parseState ; Ident.create "AwaitingKey" ])
+                        |> SynExpr.applyTo (SynExpr.listCons (SynExpr.createIdent "arg") (SynExpr.createIdent "args"))
+                    ]
+                    |> SynExpr.sequential
+                    |> SynExpr.ifThenElse includeFlagLike fail
+
             [
                 SynMatchClause.create
                     (SynPat.nameWithArgs "Ok" [ SynPat.unit ])
@@ -1144,7 +1167,7 @@ module internal ArgParserGenerator =
                     (SynPat.nameWithArgs "Error" [ SynPat.named "exc" ])
                     (SynExpr.ifThenElse
                         (SynExpr.applyFunction (SynExpr.createIdent "setFlagValue") (SynExpr.createIdent "key"))
-                        fail
+                        onFailure
                         (SynExpr.createIdent "go"
                          |> SynExpr.applyTo (SynExpr.createLongIdent' [ parseState ; Ident.create "AwaitingKey" ])
                          |> SynExpr.applyTo (SynExpr.listCons (SynExpr.createIdent "arg") (SynExpr.createIdent "args"))))

WoofWare.Myriad.Plugins/CataGenerator.fs

@@ -564,11 +564,12 @@ module internal CataGenerator =
                     let domain =
                         field.FieldName
                         |> Option.map Ident.lowerFirstLetter
-                        |> SynType.signatureParamOfType place
+                        |> SynType.signatureParamOfType [] place false
 
                     acc |> SynType.funFromDomain domain
                 )
                 |> SynMemberDefn.abstractMember
+                    []
                     case.CataMethodIdent
                     None
                     arity

WoofWare.Myriad.Plugins/InterfaceMockGenerator.fs

@@ -228,14 +228,11 @@ module internal InterfaceMockGenerator =
             x.Type
 
     let private constructMemberSinglePlace (tuple : TupledArg) : SynType =
-        match tuple.Args |> List.rev |> List.map buildType with
-        | [] -> failwith "no-arg functions not supported yet"
-        | [ x ] -> x
-        | last :: rest ->
-            ([ SynTupleTypeSegment.Type last ], rest)
-            ||> List.fold (fun ty nextArg -> SynTupleTypeSegment.Type nextArg :: SynTupleTypeSegment.Star range0 :: ty)
-            |> fun segs -> SynType.Tuple (false, segs, range0)
-        |> fun ty -> if tuple.HasParen then SynType.Paren (ty, range0) else ty
+        tuple.Args
+        |> List.map buildType
+        |> SynType.tupleNoParen
+        |> Option.defaultWith (fun () -> failwith "no-arg functions not supported yet")
+        |> if tuple.HasParen then SynType.paren else id
 
     let constructMember (mem : MemberInfo) : SynField =
         let inputType = mem.Args |> List.map constructMemberSinglePlace

WoofWare.Myriad.Plugins/SynExpr/Ident.fs

@@ -2,6 +2,7 @@ namespace WoofWare.Myriad.Plugins
 
 open System
 open System.Text
+open System.Text.RegularExpressions
 open Fantomas.FCS.Syntax
 open Fantomas.FCS.Text.Range
 
@@ -9,6 +10,53 @@ open Fantomas.FCS.Text.Range
 module internal Ident =
     let inline create (s : string) = Ident (s, range0)
 
+    /// Fantomas bug, perhaps? "type" is not rendered as ``type``, although the ASTs are identical
+    /// apart from the ranges?
+    /// Awful hack: here is a function that does this sort of thing.
+    let createSanitisedParamName (s : string) =
+        match s with
+        | "type" -> create "type'"
+        | _ ->
+
+        let result = StringBuilder ()
+
+        for i = 0 to s.Length - 1 do
+            if Char.IsLetter s.[i] then
+                result.Append s.[i] |> ignore<StringBuilder>
+            elif Char.IsNumber s.[i] then
+                if result.Length > 0 then
+                    result.Append s.[i] |> ignore<StringBuilder>
+            elif s.[i] = '_' || s.[i] = '-' then
+                result.Append '_' |> ignore<StringBuilder>
+            else
+                failwith $"could not convert to ident: %s{s}"
+
+        create (result.ToString ())
+
+    let private alnum = Regex @"^[a-zA-Z][a-zA-Z0-9]*$"
+
+    let createSanitisedTypeName (s : string) =
+        let result = StringBuilder ()
+        let mutable capitalize = true
+
+        for i = 0 to s.Length - 1 do
+            if Char.IsLetter s.[i] then
+                if capitalize then
+                    result.Append (Char.ToUpperInvariant s.[i]) |> ignore<StringBuilder>
+                    capitalize <- false
+                else
+                    result.Append s.[i] |> ignore<StringBuilder>
+            elif Char.IsNumber s.[i] then
+                if result.Length > 0 then
+                    result.Append s.[i] |> ignore<StringBuilder>
+            elif s.[i] = '_' then
+                capitalize <- true
+
+        if result.Length = 0 then
+            failwith $"String %s{s} was not suitable as a type identifier"
+
+        Ident (result.ToString (), range0)
+
     let lowerFirstLetter (x : Ident) : Ident =
         let result = StringBuilder x.idText.Length
         result.Append (Char.ToLowerInvariant x.idText.[0]) |> ignore

WoofWare.Myriad.Plugins/SynExpr/PreXmlDoc.fs

@@ -6,7 +6,12 @@ open Fantomas.FCS.Text.Range
 [<RequireQualifiedAccess>]
 module internal PreXmlDoc =
     let create (s : string) : PreXmlDoc =
-        PreXmlDoc.Create ([| " " + s |], range0)
+        let s = s.Split "\n"
+
+        for i = 0 to s.Length - 1 do
+            s.[i] <- " " + s.[i]
+
+        PreXmlDoc.Create (s, range0)
 
     let create' (s : string seq) : PreXmlDoc =
         PreXmlDoc.Create (Array.ofSeq s, range0)

WoofWare.Myriad.Plugins/SynExpr/SynArgPats.fs

@@ -9,12 +9,12 @@ module internal SynArgPats =
         match caseNames.Length with
         | 0 -> SynArgPats.Pats []
         | 1 ->
-            SynPat.Named (SynIdent.SynIdent (Ident.create caseNames.[0], None), false, None, range0)
+            SynPat.Named (SynIdent.createS caseNames.[0], false, None, range0)
             |> List.singleton
             |> SynArgPats.Pats
         | len ->
             caseNames
-            |> List.map (fun name -> SynPat.Named (SynIdent.SynIdent (Ident.create name, None), false, None, range0))
+            |> List.map (fun name -> SynPat.Named (SynIdent.createS name, false, None, range0))
             |> fun t -> SynPat.Tuple (false, t, List.replicate (len - 1) range0, range0)
             |> fun t -> SynPat.Paren (t, range0)
             |> List.singleton

WoofWare.Myriad.Plugins/SynExpr/SynAttribute.fs

@@ -5,32 +5,23 @@ open Fantomas.FCS.Text.Range
 
 [<RequireQualifiedAccess>]
 module internal SynAttribute =
-    let internal compilationRepresentation : SynAttribute =
+    let inline create (typeName : SynLongIdent) (arg : SynExpr) : SynAttribute =
         {
-            TypeName = SynLongIdent.createS "CompilationRepresentation"
-            ArgExpr =
-                [ "CompilationRepresentationFlags" ; "ModuleSuffix" ]
-                |> SynExpr.createLongIdent
-                |> SynExpr.paren
+            TypeName = typeName
+            ArgExpr = arg
             Target = None
             AppliesToGetterAndSetter = false
             Range = range0
         }
 
+    let internal compilationRepresentation : SynAttribute =
+        [ "CompilationRepresentationFlags" ; "ModuleSuffix" ]
+        |> SynExpr.createLongIdent
+        |> SynExpr.paren
+        |> create (SynLongIdent.createS "CompilationRepresentation")
+
     let internal requireQualifiedAccess : SynAttribute =
-        {
-            TypeName = SynLongIdent.createS "RequireQualifiedAccess"
-            ArgExpr = SynExpr.CreateConst ()
-            Target = None
-            AppliesToGetterAndSetter = false
-            Range = range0
-        }
+        create (SynLongIdent.createS "RequireQualifiedAccess") (SynExpr.CreateConst ())
 
     let internal autoOpen : SynAttribute =
-        {
-            TypeName = SynLongIdent.createS "AutoOpen"
-            ArgExpr = SynExpr.CreateConst ()
-            Target = None
-            AppliesToGetterAndSetter = false
-            Range = range0
-        }
+        create (SynLongIdent.createS "AutoOpen") (SynExpr.CreateConst ())

WoofWare.Myriad.Plugins/SynExpr/SynIdent.fs

@@ -0,0 +1,10 @@
+namespace WoofWare.Myriad.Plugins
+
+open Fantomas.FCS.Syntax
+
+[<RequireQualifiedAccess>]
+module internal SynIdent =
+    let inline createI (i : Ident) : SynIdent = SynIdent.SynIdent (i, None)
+
+    let inline createS (i : string) : SynIdent =
+        SynIdent.SynIdent (Ident.create i, None)

WoofWare.Myriad.Plugins/SynExpr/SynMemberDefn.fs

@@ -17,8 +17,8 @@ module internal SynMemberDefn =
             SynMemberFlags.MemberKind = SynMemberKind.Member
         }
 
-
     let abstractMember
+        (attrs : SynAttribute list)
         (ident : SynIdent)
         (typars : SynTyparDecls option)
         (arity : SynValInfo)
@@ -28,7 +28,13 @@ module internal SynMemberDefn =
         =
         let slot =
             SynValSig.SynValSig (
-                [],
+                attrs
+                |> List.map (fun attr ->
+                    {
+                        Attributes = [ attr ]
+                        Range = range0
+                    }
+                ),
                 ident,
                 SynValTyparDecls.SynValTyparDecls (typars, true),
                 returnType,

WoofWare.Myriad.Plugins/SynExpr/SynType.fs

@@ -267,6 +267,8 @@ module internal SynType =
         | SynType.Paren (ty, _) -> stripOptionalParen ty
         | ty -> ty
 
+    let inline paren (ty : SynType) : SynType = SynType.Paren (ty, range0)
+
     let inline createLongIdent (ident : LongIdent) : SynType =
         SynType.LongIdent (SynLongIdent.create ident)
 
@@ -283,6 +285,17 @@ module internal SynType =
 
     let inline app (name : string) (args : SynType list) : SynType = app' (named name) args
 
+    /// Returns None if the input list was empty.
+    let inline tupleNoParen (ty : SynType list) : SynType option =
+        match List.rev ty with
+        | [] -> None
+        | [ t ] -> Some t
+        | t :: rest ->
+            ([ SynTupleTypeSegment.Type t ], rest)
+            ||> List.fold (fun ty nextArg -> SynTupleTypeSegment.Type nextArg :: SynTupleTypeSegment.Star range0 :: ty)
+            |> fun segs -> SynType.Tuple (false, segs, range0)
+            |> Some
+
     let inline appPostfix (name : string) (arg : SynType) : SynType =
         SynType.App (named name, None, [ arg ], [], None, true, range0)
 
@@ -299,16 +312,54 @@ module internal SynType =
             }
         )
 
-    let inline signatureParamOfType (ty : SynType) (name : Ident option) : SynType =
-        SynType.SignatureParameter ([], false, name, ty, range0)
+    let inline signatureParamOfType
+        (attrs : SynAttribute list)
+        (ty : SynType)
+        (optional : bool)
+        (name : Ident option)
+        : SynType
+        =
+        SynType.SignatureParameter (
+            attrs
+            |> List.map (fun attr ->
+                {
+                    Attributes = [ attr ]
+                    Range = range0
+                }
+            ),
+            optional,
+            name,
+            ty,
+            range0
+        )
 
     let inline var (ty : SynTypar) : SynType = SynType.Var (ty, range0)
 
     let unit : SynType = named "unit"
+    let obj : SynType = named "obj"
+    let bool : SynType = named "bool"
     let int : SynType = named "int"
+    let array (elt : SynType) : SynType = SynType.Array (1, elt, range0)
+
+    let list (elt : SynType) : SynType =
+        SynType.App (named "list", None, [ elt ], [], None, true, range0)
+
+    let option (elt : SynType) : SynType =
+        SynType.App (named "option", None, [ elt ], [], None, true, range0)
 
     let anon : SynType = SynType.Anon range0
 
+    let task (elt : SynType) : SynType =
+        SynType.App (
+            createLongIdent' [ "System" ; "Threading" ; "Tasks" ; "Task" ],
+            None,
+            [ elt ],
+            [],
+            None,
+            true,
+            range0
+        )
+
     let string : SynType = named "string"
 
     /// Given ['a1, 'a2] and 'ret, returns 'a1 -> 'a2 -> 'ret.

WoofWare.Myriad.Plugins/SynExpr/SynUnionCase.fs

@@ -44,7 +44,7 @@ module internal SynUnionCase =
 
         SynUnionCase.SynUnionCase (
             SynAttributes.ofAttrs case.Attributes,
-            SynIdent.SynIdent (case.Name, None),
+            SynIdent.createI case.Name,
             SynUnionCaseKind.Fields fields,
             case.XmlDoc |> Option.defaultValue PreXmlDoc.Empty,
             case.Access,

WoofWare.Myriad.Plugins/WoofWare.Myriad.Plugins.fsproj

@@ -30,6 +30,7 @@
     <Compile Include="SynExpr\SynAttributes.fs" />
     <Compile Include="SynExpr\PreXmlDoc.fs" />
     <Compile Include="SynExpr\Ident.fs" />
+    <Compile Include="SynExpr\SynIdent.fs" />
     <Compile Include="SynExpr\SynLongIdent.fs" />
     <Compile Include="SynExpr\SynExprLetOrUseTrivia.fs" />
     <Compile Include="SynExpr\SynArgPats.fs" />