Support individual per-method headers (#268)

* Bump fantomas from 6.3.12 to 6.3.15

Bumps [fantomas](https://github.com/fsprojects/fantomas) from 6.3.12 to 6.3.15.
- [Release notes](https://github.com/fsprojects/fantomas/releases)
- [Changelog](https://github.com/fsprojects/fantomas/blob/main/CHANGELOG.md)
- [Commits](https://github.com/fsprojects/fantomas/compare/v6.3.12...v6.3.15)

---
updated-dependencies:
- dependency-name: fantomas
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* Bump FsUnit from 6.0.0 to 6.0.1

Bumps [FsUnit](https://github.com/fsprojects/FsUnit) from 6.0.0 to 6.0.1.
- [Release notes](https://github.com/fsprojects/FsUnit/releases)
- [Changelog](https://github.com/fsprojects/FsUnit/blob/master/RELEASE_NOTES.md)
- [Commits](https://github.com/fsprojects/FsUnit/compare/6.0.0...6.0.1)

---
updated-dependencies:
- dependency-name: FsUnit
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* Deps

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Smaug123 <3138005+Smaug123@users.noreply.github.com>

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "fantomas": {
-      "version": "6.3.12",
+      "version": "6.3.15",
       "commands": [
         "fantomas"
       ]

.github/workflows/dotnet.yaml

@@ -29,7 +29,7 @@ jobs:
       with:
         fetch-depth: 0 # so that NerdBank.GitVersioning has access to history
     - name: Install Nix
-      uses: cachix/install-nix-action@V27
+      uses: cachix/install-nix-action@V28
       with:
         extra_nix_config: |
           access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -50,7 +50,7 @@ jobs:
         with:
           fetch-depth: 0 # so that NerdBank.GitVersioning has access to history
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -67,7 +67,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -82,7 +82,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -97,7 +97,7 @@ jobs:
         with:
           fetch-depth: 0 # so that NerdBank.GitVersioning has access to history
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -116,7 +116,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -129,7 +129,7 @@ jobs:
     steps:
       - uses: actions/checkout@master
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -142,7 +142,7 @@ jobs:
     steps:
       - uses: actions/checkout@master
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -156,7 +156,7 @@ jobs:
       with:
         fetch-depth: 0 # so that NerdBank.GitVersioning has access to history
     - name: Install Nix
-      uses: cachix/install-nix-action@V27
+      uses: cachix/install-nix-action@V28
       with:
         extra_nix_config: |
           access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -276,7 +276,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
@@ -309,7 +309,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install Nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@V28
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

CHANGELOG.md

@@ -1,5 +1,14 @@
 Notable changes are recorded here.
 
+# WoofWare.Myriad.Plugins 3.0.1
+
+Semantics of `HttpClient`'s URI component composition changed:
+we now implicitly insert `/` characters after `[<BaseAddress>]` and `[<BasePath>]`, so that URI composition doesn't silently drop the last component if you didn't put a slash there.
+
+# WoofWare.Myriad.Plugins 2.3.9
+
+`JsonParse` and `JsonSerialize` now interpret `[<JsonExtensionData>]`, which must be on a `Dictionary<string, _>`; this collects any extra components that were present on the JSON object.
+
 # WoofWare.Myriad.Plugins 2.2.1, WoofWare.Myriad.Plugins.Attributes 3.2.1
 
 New generator: `ArgParser`, a basic reflection-free argument parser.

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

@@ -3636,7 +3636,7 @@ module FlagsIntoPositionalArgsArgParse =
                             if setFlagValue key then
                                 go ParseState_FlagsIntoPositionalArgs.AwaitingKey (arg :: args)
                             else if true then
-                                key |> arg_1.Add
+                                key |> (fun x -> x) |> arg_1.Add
                                 go ParseState_FlagsIntoPositionalArgs.AwaitingKey (arg :: args)
                             else
                                 match exc with
@@ -3675,6 +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 =
@@ -3800,7 +4292,7 @@ module FlagsIntoPositionalArgs'ArgParse =
                             if setFlagValue key then
                                 go ParseState_FlagsIntoPositionalArgs'.AwaitingKey (arg :: args)
                             else if false then
-                                key |> arg_1.Add
+                                key |> (fun x -> x) |> arg_1.Add
                                 go ParseState_FlagsIntoPositionalArgs'.AwaitingKey (arg :: args)
                             else
                                 match exc with

ConsumePlugin/GeneratedRestClient.fs

@@ -29,7 +29,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri (("v1/gyms/"), System.UriKind.Relative)
                         )
@@ -59,7 +59,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri (
                                 "v1/gyms/{gym_id}/attendance"
@@ -93,7 +93,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri (
                                 "v1/gyms/{gym_id}/attendance"
@@ -127,7 +127,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("v1/member", System.UriKind.Relative)
                         )
@@ -157,7 +157,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri (
                                 "v1/gyms/{gym}"
@@ -191,7 +191,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("v1/member/activity", System.UriKind.Relative)
                         )
@@ -221,7 +221,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("some/url", System.UriKind.Relative)
                         )
@@ -251,7 +251,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("some/url", System.UriKind.Relative)
                         )
@@ -317,7 +317,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri (
                                 ("/v2/gymSessions/member"
@@ -358,7 +358,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri (
                                 ("/v2/gymSessions/member?foo=1"
@@ -399,7 +399,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -426,7 +426,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -453,7 +453,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -480,7 +480,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -507,7 +507,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -534,7 +534,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -567,7 +567,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -600,7 +600,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -633,7 +633,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("users/new", System.UriKind.Relative)
                         )
@@ -659,7 +659,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri (
                                 "endpoint/{param}"
@@ -688,7 +688,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -713,7 +713,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -738,7 +738,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -763,7 +763,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -787,7 +787,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -811,7 +811,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -835,7 +835,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -859,7 +859,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -895,7 +895,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -931,7 +931,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -967,7 +967,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -1003,7 +1003,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -1026,7 +1026,7 @@ module PureGymApi =
                     let uri =
                         System.Uri (
                             (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
+                             | null -> System.Uri "https://whatnot.com/"
                              | v -> v),
                             System.Uri ("endpoint", System.UriKind.Relative)
                         )
@@ -1116,15 +1116,18 @@ module ApiWithBasePath =
 
                     let uri =
                         System.Uri (
-                            (match client.BaseAddress with
-                             | null ->
-                                 raise (
-                                     System.ArgumentNullException (
-                                         nameof (client.BaseAddress),
-                                         "No base address was supplied on the type, and no BaseAddress was on the HttpClient."
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null ->
+                                     raise (
+                                         System.ArgumentNullException (
+                                             nameof (client.BaseAddress),
+                                             "No base address was supplied on the type, and no BaseAddress was on the HttpClient."
+                                         )
                                      )
-                                 )
-                             | v -> v),
+                                 | v -> v),
+                                System.Uri ("foo/", System.UriKind.Relative)
+                            ),
                             System.Uri (
                                 "endpoint/{param}"
                                     .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
@@ -1167,9 +1170,12 @@ module ApiWithBasePathAndAddress =
 
                     let uri =
                         System.Uri (
-                            (match client.BaseAddress with
-                             | null -> System.Uri "https://whatnot.com"
-                             | v -> v),
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null -> System.Uri "https://whatnot.com/thing/"
+                                 | v -> v),
+                                System.Uri ("foo/", System.UriKind.Relative)
+                            ),
                             System.Uri (
                                 "endpoint/{param}"
                                     .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
@@ -1200,6 +1206,312 @@ open System.Net
 open System.Net.Http
 open RestEase
 
+/// Module for constructing a REST client.
+[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix) ; RequireQualifiedAccess>]
+module ApiWithAbsoluteBasePath =
+    /// Create a REST client.
+    let make (client : System.Net.Http.HttpClient) : IApiWithAbsoluteBasePath =
+        { new IApiWithAbsoluteBasePath with
+            member _.GetPathParam (parameter : string, cancellationToken : CancellationToken option) =
+                async {
+                    let! ct = Async.CancellationToken
+
+                    let uri =
+                        System.Uri (
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null ->
+                                     raise (
+                                         System.ArgumentNullException (
+                                             nameof (client.BaseAddress),
+                                             "No base address was supplied on the type, and no BaseAddress was on the HttpClient."
+                                         )
+                                     )
+                                 | v -> v),
+                                System.Uri ("/foo/", System.UriKind.Relative)
+                            ),
+                            System.Uri (
+                                "endpoint/{param}"
+                                    .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
+                                System.UriKind.Relative
+                            )
+                        )
+
+                    let httpMessage =
+                        new System.Net.Http.HttpRequestMessage (
+                            Method = System.Net.Http.HttpMethod.Get,
+                            RequestUri = uri
+                        )
+
+                    let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
+                    let response = response.EnsureSuccessStatusCode ()
+                    let! responseString = response.Content.ReadAsStringAsync ct |> Async.AwaitTask
+                    return responseString
+                }
+                |> (fun a -> Async.StartAsTask (a, ?cancellationToken = cancellationToken))
+        }
+namespace PureGym
+
+open System
+open System.Threading
+open System.Threading.Tasks
+open System.IO
+open System.Net
+open System.Net.Http
+open RestEase
+
+/// Module for constructing a REST client.
+[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix) ; RequireQualifiedAccess>]
+module ApiWithAbsoluteBasePathAndAddress =
+    /// Create a REST client.
+    let make (client : System.Net.Http.HttpClient) : IApiWithAbsoluteBasePathAndAddress =
+        { new IApiWithAbsoluteBasePathAndAddress with
+            member _.GetPathParam (parameter : string, ct : CancellationToken option) =
+                async {
+                    let! ct = Async.CancellationToken
+
+                    let uri =
+                        System.Uri (
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null -> System.Uri "https://whatnot.com/thing/"
+                                 | v -> v),
+                                System.Uri ("/foo/", System.UriKind.Relative)
+                            ),
+                            System.Uri (
+                                "endpoint/{param}"
+                                    .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
+                                System.UriKind.Relative
+                            )
+                        )
+
+                    let httpMessage =
+                        new System.Net.Http.HttpRequestMessage (
+                            Method = System.Net.Http.HttpMethod.Get,
+                            RequestUri = uri
+                        )
+
+                    let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
+                    let response = response.EnsureSuccessStatusCode ()
+                    let! responseString = response.Content.ReadAsStringAsync ct |> Async.AwaitTask
+                    return responseString
+                }
+                |> (fun a -> Async.StartAsTask (a, ?cancellationToken = ct))
+        }
+namespace PureGym
+
+open System
+open System.Threading
+open System.Threading.Tasks
+open System.IO
+open System.Net
+open System.Net.Http
+open RestEase
+
+/// Module for constructing a REST client.
+[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix) ; RequireQualifiedAccess>]
+module ApiWithBasePathAndAbsoluteEndpoint =
+    /// Create a REST client.
+    let make (client : System.Net.Http.HttpClient) : IApiWithBasePathAndAbsoluteEndpoint =
+        { new IApiWithBasePathAndAbsoluteEndpoint with
+            member _.GetPathParam (parameter : string, cancellationToken : CancellationToken option) =
+                async {
+                    let! ct = Async.CancellationToken
+
+                    let uri =
+                        System.Uri (
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null ->
+                                     raise (
+                                         System.ArgumentNullException (
+                                             nameof (client.BaseAddress),
+                                             "No base address was supplied on the type, and no BaseAddress was on the HttpClient."
+                                         )
+                                     )
+                                 | v -> v),
+                                System.Uri ("foo/", System.UriKind.Relative)
+                            ),
+                            System.Uri (
+                                "/endpoint/{param}"
+                                    .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
+                                System.UriKind.Relative
+                            )
+                        )
+
+                    let httpMessage =
+                        new System.Net.Http.HttpRequestMessage (
+                            Method = System.Net.Http.HttpMethod.Get,
+                            RequestUri = uri
+                        )
+
+                    let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
+                    let response = response.EnsureSuccessStatusCode ()
+                    let! responseString = response.Content.ReadAsStringAsync ct |> Async.AwaitTask
+                    return responseString
+                }
+                |> (fun a -> Async.StartAsTask (a, ?cancellationToken = cancellationToken))
+        }
+namespace PureGym
+
+open System
+open System.Threading
+open System.Threading.Tasks
+open System.IO
+open System.Net
+open System.Net.Http
+open RestEase
+
+/// Module for constructing a REST client.
+[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix) ; RequireQualifiedAccess>]
+module ApiWithBasePathAndAddressAndAbsoluteEndpoint =
+    /// Create a REST client.
+    let make (client : System.Net.Http.HttpClient) : IApiWithBasePathAndAddressAndAbsoluteEndpoint =
+        { new IApiWithBasePathAndAddressAndAbsoluteEndpoint with
+            member _.GetPathParam (parameter : string, ct : CancellationToken option) =
+                async {
+                    let! ct = Async.CancellationToken
+
+                    let uri =
+                        System.Uri (
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null -> System.Uri "https://whatnot.com/thing/"
+                                 | v -> v),
+                                System.Uri ("foo/", System.UriKind.Relative)
+                            ),
+                            System.Uri (
+                                "/endpoint/{param}"
+                                    .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
+                                System.UriKind.Relative
+                            )
+                        )
+
+                    let httpMessage =
+                        new System.Net.Http.HttpRequestMessage (
+                            Method = System.Net.Http.HttpMethod.Get,
+                            RequestUri = uri
+                        )
+
+                    let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
+                    let response = response.EnsureSuccessStatusCode ()
+                    let! responseString = response.Content.ReadAsStringAsync ct |> Async.AwaitTask
+                    return responseString
+                }
+                |> (fun a -> Async.StartAsTask (a, ?cancellationToken = ct))
+        }
+namespace PureGym
+
+open System
+open System.Threading
+open System.Threading.Tasks
+open System.IO
+open System.Net
+open System.Net.Http
+open RestEase
+
+/// Module for constructing a REST client.
+[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix) ; RequireQualifiedAccess>]
+module ApiWithAbsoluteBasePathAndAbsoluteEndpoint =
+    /// Create a REST client.
+    let make (client : System.Net.Http.HttpClient) : IApiWithAbsoluteBasePathAndAbsoluteEndpoint =
+        { new IApiWithAbsoluteBasePathAndAbsoluteEndpoint with
+            member _.GetPathParam (parameter : string, cancellationToken : CancellationToken option) =
+                async {
+                    let! ct = Async.CancellationToken
+
+                    let uri =
+                        System.Uri (
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null ->
+                                     raise (
+                                         System.ArgumentNullException (
+                                             nameof (client.BaseAddress),
+                                             "No base address was supplied on the type, and no BaseAddress was on the HttpClient."
+                                         )
+                                     )
+                                 | v -> v),
+                                System.Uri ("/foo/", System.UriKind.Relative)
+                            ),
+                            System.Uri (
+                                "/endpoint/{param}"
+                                    .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
+                                System.UriKind.Relative
+                            )
+                        )
+
+                    let httpMessage =
+                        new System.Net.Http.HttpRequestMessage (
+                            Method = System.Net.Http.HttpMethod.Get,
+                            RequestUri = uri
+                        )
+
+                    let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
+                    let response = response.EnsureSuccessStatusCode ()
+                    let! responseString = response.Content.ReadAsStringAsync ct |> Async.AwaitTask
+                    return responseString
+                }
+                |> (fun a -> Async.StartAsTask (a, ?cancellationToken = cancellationToken))
+        }
+namespace PureGym
+
+open System
+open System.Threading
+open System.Threading.Tasks
+open System.IO
+open System.Net
+open System.Net.Http
+open RestEase
+
+/// Module for constructing a REST client.
+[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix) ; RequireQualifiedAccess>]
+module ApiWithAbsoluteBasePathAndAddressAndAbsoluteEndpoint =
+    /// Create a REST client.
+    let make (client : System.Net.Http.HttpClient) : IApiWithAbsoluteBasePathAndAddressAndAbsoluteEndpoint =
+        { new IApiWithAbsoluteBasePathAndAddressAndAbsoluteEndpoint with
+            member _.GetPathParam (parameter : string, ct : CancellationToken option) =
+                async {
+                    let! ct = Async.CancellationToken
+
+                    let uri =
+                        System.Uri (
+                            System.Uri (
+                                (match client.BaseAddress with
+                                 | null -> System.Uri "https://whatnot.com/thing/"
+                                 | v -> v),
+                                System.Uri ("/foo/", System.UriKind.Relative)
+                            ),
+                            System.Uri (
+                                "/endpoint/{param}"
+                                    .Replace ("{param}", parameter.ToString () |> System.Web.HttpUtility.UrlEncode),
+                                System.UriKind.Relative
+                            )
+                        )
+
+                    let httpMessage =
+                        new System.Net.Http.HttpRequestMessage (
+                            Method = System.Net.Http.HttpMethod.Get,
+                            RequestUri = uri
+                        )
+
+                    let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
+                    let response = response.EnsureSuccessStatusCode ()
+                    let! responseString = response.Content.ReadAsStringAsync ct |> Async.AwaitTask
+                    return responseString
+                }
+                |> (fun a -> Async.StartAsTask (a, ?cancellationToken = ct))
+        }
+namespace PureGym
+
+open System
+open System.Threading
+open System.Threading.Tasks
+open System.IO
+open System.Net
+open System.Net.Http
+open RestEase
+
 /// Module for constructing a REST client.
 [<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix) ; RequireQualifiedAccess>]
 module ApiWithHeaders =
@@ -1245,6 +1557,7 @@ module ApiWithHeaders =
                     do httpMessage.Headers.Add ("X-Foo", this.SomeHeader.ToString ())
                     do httpMessage.Headers.Add ("Authorization", this.SomeOtherHeader.ToString ())
                     do httpMessage.Headers.Add ("Header-Name", "Header-Value")
+                    do httpMessage.Headers.Add ("Something-Else", "val")
                     let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
                     let response = response.EnsureSuccessStatusCode ()
                     let! responseString = response.Content.ReadAsStringAsync ct |> Async.AwaitTask

ConsumePlugin/GeneratedSerde.fs

@@ -210,6 +210,8 @@ module JsonRecordTypeWithBothJsonSerializeExtension =
                      |> (fun field -> field.ToString "o" |> System.Text.Json.Nodes.JsonValue.Create<string>))
                 )
 
+                node.Add ("unit", (input.Unit |> (fun value -> System.Text.Json.Nodes.JsonObject ())))
+
             node :> _
 namespace ConsumePlugin
 
@@ -291,6 +293,60 @@ module FooJsonSerializeExtension =
                 )
 
             node :> _
+namespace ConsumePlugin
+
+open System
+open System.Collections.Generic
+open System.Text.Json.Serialization
+
+/// Module containing JSON serializing extension members for the CollectRemaining type
+[<AutoOpen>]
+module CollectRemainingJsonSerializeExtension =
+    /// Extension methods for JSON parsing
+    type CollectRemaining with
+
+        /// Serialize to a JSON node
+        static member toJsonNode (input : CollectRemaining) : System.Text.Json.Nodes.JsonNode =
+            let node = System.Text.Json.Nodes.JsonObject ()
+
+            do
+                node.Add (
+                    "message",
+                    (input.Message
+                     |> (fun field ->
+                         match field with
+                         | None -> null :> System.Text.Json.Nodes.JsonNode
+                         | Some field -> HeaderAndValue.toJsonNode field
+                     ))
+                )
+
+                for KeyValue (key, value) in input.Rest do
+                    node.Add (key, id value)
+
+            node :> _
+namespace ConsumePlugin
+
+open System
+open System.Collections.Generic
+open System.Text.Json.Serialization
+
+/// Module containing JSON serializing extension members for the OuterCollectRemaining type
+[<AutoOpen>]
+module OuterCollectRemainingJsonSerializeExtension =
+    /// Extension methods for JSON parsing
+    type OuterCollectRemaining with
+
+        /// Serialize to a JSON node
+        static member toJsonNode (input : OuterCollectRemaining) : System.Text.Json.Nodes.JsonNode =
+            let node = System.Text.Json.Nodes.JsonObject ()
+
+            do
+                for KeyValue (key, value) in input.Others do
+                    node.Add (key, System.Text.Json.Nodes.JsonValue.Create<int> value)
+
+                node.Add ("remaining", (input.Remaining |> CollectRemaining.toJsonNode))
+
+            node :> _
 
 namespace ConsumePlugin
 
@@ -424,6 +480,8 @@ module JsonRecordTypeWithBothJsonParseExtension =
 
         /// Parse from a JSON node.
         static member jsonParse (node : System.Text.Json.Nodes.JsonNode) : JsonRecordTypeWithBoth =
+            let arg_21 = ()
+
             let arg_20 =
                 (match node.["timestamp"] with
                  | null ->
@@ -705,6 +763,7 @@ module JsonRecordTypeWithBothJsonParseExtension =
                 IntMeasureNullable = arg_18
                 Enum = arg_19
                 Timestamp = arg_20
+                Unit = arg_21
             }
 namespace ConsumePlugin
 
@@ -842,3 +901,83 @@ module FooJsonParseExtension =
             {
                 Message = arg_0
             }
+namespace ConsumePlugin
+
+/// Module containing JSON parsing extension members for the CollectRemaining type
+[<AutoOpen>]
+module CollectRemainingJsonParseExtension =
+    /// Extension methods for JSON parsing
+    type CollectRemaining with
+
+        /// Parse from a JSON node.
+        static member jsonParse (node : System.Text.Json.Nodes.JsonNode) : CollectRemaining =
+            let arg_1 =
+                let result =
+                    System.Collections.Generic.Dictionary<string, System.Text.Json.Nodes.JsonNode> ()
+
+                let node = node.AsObject ()
+
+                for KeyValue (key, value) in node do
+                    if key = "message" then () else result.Add (key, node.[key])
+
+                result
+
+            let arg_0 =
+                match node.["message"] with
+                | null -> None
+                | v -> HeaderAndValue.jsonParse v |> Some
+
+            {
+                Message = arg_0
+                Rest = arg_1
+            }
+namespace ConsumePlugin
+
+/// Module containing JSON parsing extension members for the OuterCollectRemaining type
+[<AutoOpen>]
+module OuterCollectRemainingJsonParseExtension =
+    /// Extension methods for JSON parsing
+    type OuterCollectRemaining with
+
+        /// Parse from a JSON node.
+        static member jsonParse (node : System.Text.Json.Nodes.JsonNode) : OuterCollectRemaining =
+            let arg_1 =
+                CollectRemaining.jsonParse (
+                    match node.["remaining"] with
+                    | null ->
+                        raise (
+                            System.Collections.Generic.KeyNotFoundException (
+                                sprintf "Required key '%s' not found on JSON object" ("remaining")
+                            )
+                        )
+                    | v -> v
+                )
+
+            let arg_0 =
+                let result = System.Collections.Generic.Dictionary<string, int> ()
+                let node = node.AsObject ()
+
+                for KeyValue (key, value) in node do
+                    if key = "remaining" then
+                        ()
+                    else
+                        result.Add (
+                            key,
+                            (match node.[key] with
+                             | null ->
+                                 raise (
+                                     System.Collections.Generic.KeyNotFoundException (
+                                         sprintf "Required key '%s' not found on JSON object" (key)
+                                     )
+                                 )
+                             | v -> v)
+                                .AsValue()
+                                .GetValue<System.Int32> ()
+                        )
+
+                result
+
+            {
+                Others = arg_0
+                Remaining = arg_1
+            }

ConsumePlugin/RestApiExample.fs

@@ -122,8 +122,6 @@ type internal IApiWithoutBaseAddress =
     [<Get "endpoint/{param}">]
     abstract GetPathParam : [<Path "param">] parameter : string * ?ct : CancellationToken -> Task<string>
 
-// TODO: implement BasePath support
-
 [<WoofWare.Myriad.Plugins.HttpClient>]
 [<BasePath "foo">]
 type IApiWithBasePath =
@@ -132,12 +130,54 @@ type IApiWithBasePath =
     abstract GetPathParam : [<Path "param">] parameter : string * ?cancellationToken : CancellationToken -> Task<string>
 
 [<WoofWare.Myriad.Plugins.HttpClient>]
-[<BaseAddress "https://whatnot.com">]
+[<BaseAddress "https://whatnot.com/thing">]
 [<BasePath "foo">]
 type IApiWithBasePathAndAddress =
     [<Get "endpoint/{param}">]
     abstract GetPathParam : [<Path "param">] parameter : string * ?ct : CancellationToken -> Task<string>
 
+[<WoofWare.Myriad.Plugins.HttpClient>]
+[<BasePath "/foo">]
+type IApiWithAbsoluteBasePath =
+    // Example where we use the bundled attributes rather than RestEase's
+    [<WoofWare.Myriad.Plugins.RestEase.Get "endpoint/{param}">]
+    abstract GetPathParam : [<Path "param">] parameter : string * ?cancellationToken : CancellationToken -> Task<string>
+
+[<WoofWare.Myriad.Plugins.HttpClient>]
+[<BaseAddress "https://whatnot.com/thing">]
+[<BasePath "/foo">]
+type IApiWithAbsoluteBasePathAndAddress =
+    [<Get "endpoint/{param}">]
+    abstract GetPathParam : [<Path "param">] parameter : string * ?ct : CancellationToken -> Task<string>
+
+[<WoofWare.Myriad.Plugins.HttpClient>]
+[<BasePath "foo">]
+type IApiWithBasePathAndAbsoluteEndpoint =
+    // Example where we use the bundled attributes rather than RestEase's
+    [<WoofWare.Myriad.Plugins.RestEase.Get "/endpoint/{param}">]
+    abstract GetPathParam : [<Path "param">] parameter : string * ?cancellationToken : CancellationToken -> Task<string>
+
+[<WoofWare.Myriad.Plugins.HttpClient>]
+[<BaseAddress "https://whatnot.com/thing">]
+[<BasePath "foo">]
+type IApiWithBasePathAndAddressAndAbsoluteEndpoint =
+    [<Get "/endpoint/{param}">]
+    abstract GetPathParam : [<Path "param">] parameter : string * ?ct : CancellationToken -> Task<string>
+
+[<WoofWare.Myriad.Plugins.HttpClient>]
+[<BasePath "/foo">]
+type IApiWithAbsoluteBasePathAndAbsoluteEndpoint =
+    // Example where we use the bundled attributes rather than RestEase's
+    [<WoofWare.Myriad.Plugins.RestEase.Get "/endpoint/{param}">]
+    abstract GetPathParam : [<Path "param">] parameter : string * ?cancellationToken : CancellationToken -> Task<string>
+
+[<WoofWare.Myriad.Plugins.HttpClient>]
+[<BaseAddress "https://whatnot.com/thing">]
+[<BasePath "/foo">]
+type IApiWithAbsoluteBasePathAndAddressAndAbsoluteEndpoint =
+    [<Get "/endpoint/{param}">]
+    abstract GetPathParam : [<Path "param">] parameter : string * ?ct : CancellationToken -> Task<string>
+
 [<WoofWare.Myriad.Plugins.HttpClient>]
 [<Header("Header-Name", "Header-Value")>]
 type IApiWithHeaders =
@@ -148,6 +188,7 @@ type IApiWithHeaders =
     abstract SomeOtherHeader : int
 
     [<Get "endpoint/{param}">]
+    [<Header("Something-Else", "val")>]
     abstract GetPathParam : [<Path "param">] parameter : string * ?ct : CancellationToken -> Task<string>
 
 [<WoofWare.Myriad.Plugins.HttpClient>]

ConsumePlugin/SerializationAndDeserialization.fs

@@ -50,6 +50,7 @@ type JsonRecordTypeWithBoth =
         IntMeasureNullable : int<measure> Nullable
         Enum : SomeEnum
         Timestamp : DateTimeOffset
+        Unit : unit
     }
 
 [<WoofWare.Myriad.Plugins.JsonSerialize true>]
@@ -73,3 +74,21 @@ type Foo =
     {
         Message : HeaderAndValue option
     }
+
+[<WoofWare.Myriad.Plugins.JsonSerialize true>]
+[<WoofWare.Myriad.Plugins.JsonParse true>]
+type CollectRemaining =
+    {
+        Message : HeaderAndValue option
+        [<JsonExtensionData>]
+        Rest : Dictionary<string, System.Text.Json.Nodes.JsonNode>
+    }
+
+[<WoofWare.Myriad.Plugins.JsonSerialize true>]
+[<WoofWare.Myriad.Plugins.JsonParse true>]
+type OuterCollectRemaining =
+    {
+        [<JsonExtensionData>]
+        Others : Dictionary<string, int>
+        Remaining : CollectRemaining
+    }

WoofWare.Myriad.Plugins.Attributes/RestEase.fs

@@ -45,6 +45,9 @@ module RestEase =
 
     /// Indicates that this interface represents a REST client which accesses an API whose paths are
     /// all relative to the given address.
+    ///
+    /// We will essentially unconditionally append a slash to this for you, on the grounds that you probably don't
+    /// intend the base path *itself* to be an endpoint.
     type BaseAddressAttribute (addr : string) =
         inherit Attribute ()
 
@@ -61,3 +64,21 @@ module RestEase =
         inherit Attribute ()
         new (path : string) = PathAttribute (Some path)
         new () = PathAttribute None
+
+    /// Indicates that this argument to a method is passed to the remote API by being serialised into the request
+    /// body.
+    type BodyAttribute () =
+        inherit Attribute ()
+
+    /// This is interpolated into every URL, between the BaseAddress and the path specified by e.g. [<Get>].
+    /// Note that if the [<Get>]-specified path starts with a slash, the BasePath is ignored, because then [<Get>]
+    /// is considered to be relative to the URL root (i.e. the host part of the BaseAddress).
+    /// Similarly, if the [<BasePath>] starts with a slash, then any path component of the BaseAddress is ignored.
+    ///
+    /// We will essentially unconditionally append a slash to this for you, on the grounds that you probably don't
+    /// intend the base path *itself* to be an endpoint.
+    ///
+    /// Can contain {placeholders}; hopefully your methods define values for those placeholders with [<Path>]
+    /// attributes!
+    type BasePathAttribute (path : string) =
+        inherit Attribute ()

WoofWare.Myriad.Plugins.Attributes/SurfaceBaseline.txt

@@ -49,6 +49,10 @@ WoofWare.Myriad.Plugins.RemoveOptionsAttribute..ctor [constructor]: unit
 WoofWare.Myriad.Plugins.RestEase inherit obj
 WoofWare.Myriad.Plugins.RestEase+BaseAddressAttribute inherit System.Attribute
 WoofWare.Myriad.Plugins.RestEase+BaseAddressAttribute..ctor [constructor]: string
+WoofWare.Myriad.Plugins.RestEase+BasePathAttribute inherit System.Attribute
+WoofWare.Myriad.Plugins.RestEase+BasePathAttribute..ctor [constructor]: string
+WoofWare.Myriad.Plugins.RestEase+BodyAttribute inherit System.Attribute
+WoofWare.Myriad.Plugins.RestEase+BodyAttribute..ctor [constructor]: unit
 WoofWare.Myriad.Plugins.RestEase+DeleteAttribute inherit System.Attribute
 WoofWare.Myriad.Plugins.RestEase+DeleteAttribute..ctor [constructor]: string
 WoofWare.Myriad.Plugins.RestEase+GetAttribute inherit System.Attribute

WoofWare.Myriad.Plugins.Attributes/version.json

@@ -1,5 +1,5 @@
 {
-  "version": "3.5",
+  "version": "3.6",
   "publicReleaseRefSpec": [
     "^refs/heads/main$"
   ],

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

@@ -640,6 +640,45 @@ Required argument '--exact' received no value"""
                 GrabEverything = [ "--c" ; "hi" ; "--help" ]
             }
 
+    [<Test>]
+    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"

WoofWare.Myriad.Plugins.Test/TestHttpClient/TestBasePath.fs

@@ -9,18 +9,18 @@ open FsUnitTyped
 
 [<TestFixture>]
 module TestBasePath =
+    let replyWithUrl (message : HttpRequestMessage) : HttpResponseMessage Async =
+        async {
+            message.Method |> shouldEqual HttpMethod.Get
+            let content = new StringContent (message.RequestUri.ToString ())
+            let resp = new HttpResponseMessage (HttpStatusCode.OK)
+            resp.Content <- content
+            return resp
+        }
+
     [<Test>]
     let ``Base address is respected`` () =
-        let proc (message : HttpRequestMessage) : HttpResponseMessage Async =
-            async {
-                message.Method |> shouldEqual HttpMethod.Get
-                let content = new StringContent (message.RequestUri.ToString ())
-                let resp = new HttpResponseMessage (HttpStatusCode.OK)
-                resp.Content <- content
-                return resp
-            }
-
-        use client = HttpClientMock.makeNoUri proc
+        use client = HttpClientMock.makeNoUri replyWithUrl
         let api = PureGymApi.make client
 
         let observedUri = api.GetPathParam("param").Result
@@ -28,38 +28,28 @@ module TestBasePath =
 
     [<Test>]
     let ``Without a base address attr but with BaseAddress on client, request goes through`` () =
-        let proc (message : HttpRequestMessage) : HttpResponseMessage Async =
-            async {
-                message.Method |> shouldEqual HttpMethod.Get
-                let content = new StringContent (message.RequestUri.ToString ())
-                let resp = new HttpResponseMessage (HttpStatusCode.OK)
-                resp.Content <- content
-                return resp
-            }
-
-        use client = HttpClientMock.make (System.Uri "https://baseaddress.com") proc
+        use client = HttpClientMock.make (Uri "https://baseaddress.com") replyWithUrl
         let api = ApiWithoutBaseAddress.make client
 
         let observedUri = api.GetPathParam("param").Result
         observedUri |> shouldEqual "https://baseaddress.com/endpoint/param"
 
     [<Test>]
-    let ``Without a base address attr or BaseAddress on client, request throws`` () =
-        let proc (message : HttpRequestMessage) : HttpResponseMessage Async =
-            async {
-                message.Method |> shouldEqual HttpMethod.Get
-                let content = new StringContent (message.RequestUri.ToString ())
-                let resp = new HttpResponseMessage (HttpStatusCode.OK)
-                resp.Content <- content
-                return resp
-            }
+    let ``Base address on client takes precedence`` () =
+        use client = HttpClientMock.make (Uri "https://baseaddress.com") replyWithUrl
+        let api = PureGymApi.make client
 
-        use client = HttpClientMock.makeNoUri proc
+        let observedUri = api.GetPathParam("param").Result
+        observedUri |> shouldEqual "https://baseaddress.com/endpoint/param"
+
+    [<Test>]
+    let ``Without a base address attr or BaseAddress on client, request throws`` () =
+        use client = HttpClientMock.makeNoUri replyWithUrl
         let api = ApiWithoutBaseAddress.make client
 
         let observedExc =
             async {
-                let! result = api.GetPathParam ("param") |> Async.AwaitTask |> Async.Catch
+                let! result = api.GetPathParam "param" |> Async.AwaitTask |> Async.Catch
 
                 match result with
                 | Choice1Of2 _ -> return failwith "test failure"
@@ -78,3 +68,103 @@ module TestBasePath =
         observedExc.Message
         |> shouldEqual
             "No base address was supplied on the type, and no BaseAddress was on the HttpClient. (Parameter 'BaseAddress')"
+
+    [<Test>]
+    let ``Relative base path, no base address, relative attribute`` () : unit =
+        do
+            use client = HttpClientMock.makeNoUri replyWithUrl
+            let api = ApiWithBasePath.make client
+
+            let exc =
+                Assert.Throws<AggregateException> (fun () -> api.GetPathParam("hi").Result |> ignore<string>)
+
+            exc.InnerException.Message
+            |> shouldEqual
+                "No base address was supplied on the type, and no BaseAddress was on the HttpClient. (Parameter 'BaseAddress')"
+
+        use client = HttpClientMock.make (Uri "https://whatnot.com/thing/") replyWithUrl
+        let api = ApiWithBasePath.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/thing/foo/endpoint/hi"
+
+    [<Test>]
+    let ``Relative base path, base address, relative attribute`` () : unit =
+        use client = HttpClientMock.makeNoUri replyWithUrl
+        let api = ApiWithBasePathAndAddress.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/thing/foo/endpoint/hi"
+
+    [<Test>]
+    let ``Absolute base path, no base address, relative attribute`` () : unit =
+        do
+            use client = HttpClientMock.makeNoUri replyWithUrl
+            let api = ApiWithAbsoluteBasePath.make client
+
+            let exc =
+                Assert.Throws<AggregateException> (fun () -> api.GetPathParam("hi").Result |> ignore<string>)
+
+            exc.InnerException.Message
+            |> shouldEqual
+                "No base address was supplied on the type, and no BaseAddress was on the HttpClient. (Parameter 'BaseAddress')"
+
+        use client = HttpClientMock.make (Uri "https://whatnot.com/thing/") replyWithUrl
+        let api = ApiWithAbsoluteBasePath.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/foo/endpoint/hi"
+
+    [<Test>]
+    let ``Absolute base path, base address, relative attribute`` () : unit =
+        use client = HttpClientMock.makeNoUri replyWithUrl
+        let api = ApiWithAbsoluteBasePathAndAddress.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/foo/endpoint/hi"
+
+    [<Test>]
+    let ``Relative base path, no base address, absolute attribute`` () : unit =
+        do
+            use client = HttpClientMock.makeNoUri replyWithUrl
+            let api = ApiWithBasePathAndAbsoluteEndpoint.make client
+
+            let exc =
+                Assert.Throws<AggregateException> (fun () -> api.GetPathParam("hi").Result |> ignore<string>)
+
+            exc.InnerException.Message
+            |> shouldEqual
+                "No base address was supplied on the type, and no BaseAddress was on the HttpClient. (Parameter 'BaseAddress')"
+
+        use client = HttpClientMock.make (Uri "https://whatnot.com/thing/") replyWithUrl
+        let api = ApiWithBasePathAndAbsoluteEndpoint.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/endpoint/hi"
+
+    [<Test>]
+    let ``Relative base path, base address, absolute attribute`` () : unit =
+        use client = HttpClientMock.makeNoUri replyWithUrl
+        let api = ApiWithBasePathAndAddressAndAbsoluteEndpoint.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/endpoint/hi"
+
+    [<Test>]
+    let ``Absolute base path, no base address, absolute attribute`` () : unit =
+        do
+            use client = HttpClientMock.makeNoUri replyWithUrl
+            let api = ApiWithAbsoluteBasePathAndAbsoluteEndpoint.make client
+
+            let exc =
+                Assert.Throws<AggregateException> (fun () -> api.GetPathParam("hi").Result |> ignore<string>)
+
+            exc.InnerException.Message
+            |> shouldEqual
+                "No base address was supplied on the type, and no BaseAddress was on the HttpClient. (Parameter 'BaseAddress')"
+
+        use client = HttpClientMock.make (Uri "https://whatnot.com/thing/") replyWithUrl
+        let api = ApiWithAbsoluteBasePathAndAbsoluteEndpoint.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/endpoint/hi"
+
+    [<Test>]
+    let ``Absolute base path, base address, absolute attribute`` () : unit =
+        use client = HttpClientMock.makeNoUri replyWithUrl
+        let api = ApiWithAbsoluteBasePathAndAddressAndAbsoluteEndpoint.make client
+        let result = api.GetPathParam("hi").Result
+        result |> shouldEqual "https://whatnot.com/endpoint/hi"

WoofWare.Myriad.Plugins.Test/TestHttpClient/TestVariableHeader.fs

@@ -52,7 +52,13 @@ module TestVariableHeader =
 
         api.GetPathParam("param").Result.Split "\n"
         |> Array.sort
-        |> shouldEqual [| "Authorization: -99" ; "Header-Name: Header-Value" ; "X-Foo: 11" |]
+        |> shouldEqual
+            [|
+                "Authorization: -99"
+                "Header-Name: Header-Value"
+                "Something-Else: val"
+                "X-Foo: 11"
+            |]
 
         someHeaderCount.Value |> shouldEqual 11
         someOtherHeaderCount.Value |> shouldEqual -99
@@ -98,11 +104,23 @@ module TestVariableHeader =
 
         api.GetPathParam("param").Result.Split "\n"
         |> Array.sort
-        |> shouldEqual [| "Authorization: -99" ; "Header-Name: Header-Value" ; "X-Foo: 11" |]
+        |> shouldEqual
+            [|
+                "Authorization: -99"
+                "Header-Name: Header-Value"
+                "Something-Else: val"
+                "X-Foo: 11"
+            |]
 
         api.GetPathParam("param").Result.Split "\n"
         |> Array.sort
-        |> shouldEqual [| "Authorization: -98" ; "Header-Name: Header-Value" ; "X-Foo: 12" |]
+        |> shouldEqual
+            [|
+                "Authorization: -98"
+                "Header-Name: Header-Value"
+                "Something-Else: val"
+                "X-Foo: 12"
+            |]
 
         someHeaderCount.Value |> shouldEqual 12
         someOtherHeaderCount.Value |> shouldEqual -98

WoofWare.Myriad.Plugins.Test/TestJsonSerialize/TestJsonSerde.fs

@@ -117,6 +117,7 @@ module TestJsonSerde =
                     IntMeasureNullable = intMeasureNullable
                     Enum = enum<SomeEnum> someEnum
                     Timestamp = timestamp
+                    Unit = ()
                 }
         }
 
@@ -168,6 +169,7 @@ module TestJsonSerde =
                 IntMeasureNullable = Nullable -883<measure>
                 Enum = enum<SomeEnum> 1
                 Timestamp = DateTimeOffset (2024, 07, 01, 17, 54, 00, TimeSpan.FromHours 1.0)
+                Unit = ()
             }
 
         let expected =
@@ -198,7 +200,8 @@ module TestJsonSerde =
     "intMeasureOption": 981,
     "intMeasureNullable": -883,
     "enum": 1,
-    "timestamp": "2024-07-01T17:54:00.0000000\u002B01:00"
+    "timestamp": "2024-07-01T17:54:00.0000000\u002B01:00",
+    "unit": {}
 }
 """
             |> fun s -> s.ToCharArray ()
@@ -306,3 +309,166 @@ module TestJsonSerde =
 
         for i in counts do
             i |> shouldBeGreaterThan 0
+
+    let dict<'a, 'b when 'a : equality> (xs : ('a * 'b) seq) : Dictionary<'a, 'b> =
+        let result = Dictionary ()
+
+        for k, v in xs do
+            result.Add (k, v)
+
+        result
+
+    let inline makeJsonArr< ^t, ^u when ^u : (static member op_Implicit : ^t -> JsonNode) and ^u :> JsonNode>
+        (arr : ^t seq)
+        : JsonNode
+        =
+        let result = JsonArray ()
+
+        for a in arr do
+            result.Add a
+
+        result :> JsonNode
+
+    let normalise (d : Dictionary<'a, 'b>) : ('a * 'b) list =
+        d |> Seq.map (fun (KeyValue (a, b)) -> a, b) |> Seq.toList |> List.sortBy fst
+
+    [<Test>]
+    let ``Can collect extension data`` () =
+        let str =
+            """{
+    "message": { "header": "hi", "value": "bye" },
+    "something": 3,
+    "arr": ["egg", "toast"],
+    "str": "whatnot"
+}"""
+            |> JsonNode.Parse
+
+        let expected =
+            {
+                Rest =
+                    [
+                        "something", JsonNode.op_Implicit 3
+                        "arr", makeJsonArr [| "egg" ; "toast" |]
+                        "str", JsonNode.op_Implicit "whatnot"
+                    ]
+                    |> dict
+                Message =
+                    Some
+                        {
+                            Header = "hi"
+                            Value = "bye"
+                        }
+            }
+
+        let actual = CollectRemaining.jsonParse str
+
+        actual.Message |> shouldEqual expected.Message
+
+        normalise actual.Rest
+        |> List.map (fun (k, v) -> k, v.ToJsonString ())
+        |> shouldEqual (normalise expected.Rest |> List.map (fun (k, v) -> k, v.ToJsonString ()))
+
+    [<Test>]
+    let ``Can write out extension data`` () =
+        let expected =
+            """{"message":{"header":"hi","value":"bye"},"something":3,"arr":["egg","toast"],"str":"whatnot"}"""
+
+        let toWrite =
+            {
+                Rest =
+                    [
+                        "something", JsonNode.op_Implicit 3
+                        "arr", makeJsonArr [| "egg" ; "toast" |]
+                        "str", JsonNode.op_Implicit "whatnot"
+                    ]
+                    |> dict
+                Message =
+                    Some
+                        {
+                            Header = "hi"
+                            Value = "bye"
+                        }
+            }
+
+        let actual = CollectRemaining.toJsonNode toWrite |> fun s -> s.ToJsonString ()
+
+        actual |> shouldEqual expected
+
+    [<Test>]
+    let ``Can collect extension data, nested`` () =
+        let str =
+            """{
+  "thing": 99,
+  "baz": -123,
+  "remaining": {
+    "message": { "header": "hi", "value": "bye" },
+    "something": 3,
+    "arr": ["egg", "toast"],
+    "str": "whatnot"
+  }
+}"""
+            |> JsonNode.Parse
+
+        let expected : OuterCollectRemaining =
+            {
+                Remaining =
+                    {
+                        Message =
+                            Some
+                                {
+                                    Header = "hi"
+                                    Value = "bye"
+                                }
+                        Rest =
+                            [
+                                "something", JsonNode.op_Implicit 3
+                                "arr", makeJsonArr [| "egg" ; "toast" |]
+                                "str", JsonNode.op_Implicit "whatnot"
+                            ]
+                            |> dict
+                    }
+                Others = [ "thing", 99 ; "baz", -123 ] |> dict
+            }
+
+        let actual = OuterCollectRemaining.jsonParse str
+
+        normalise actual.Others |> shouldEqual (normalise expected.Others)
+
+        let actual = actual.Remaining
+        let expected = expected.Remaining
+
+        actual.Message |> shouldEqual expected.Message
+
+        normalise actual.Rest
+        |> List.map (fun (k, v) -> k, v.ToJsonString ())
+        |> shouldEqual (normalise expected.Rest |> List.map (fun (k, v) -> k, v.ToJsonString ()))
+
+    [<Test>]
+    let ``Can write out extension data, nested`` () =
+        let expected =
+            """{"thing":99,"baz":-123,"remaining":{"message":{"header":"hi","value":"bye"},"something":3,"arr":["egg","toast"],"str":"whatnot"}}"""
+
+        let toWrite : OuterCollectRemaining =
+            {
+                Others = [ "thing", 99 ; "baz", -123 ] |> dict
+                Remaining =
+                    {
+                        Rest =
+                            [
+                                "something", JsonNode.op_Implicit 3
+                                "arr", makeJsonArr [| "egg" ; "toast" |]
+                                "str", JsonNode.op_Implicit "whatnot"
+                            ]
+                            |> dict
+                        Message =
+                            Some
+                                {
+                                    Header = "hi"
+                                    Value = "bye"
+                                }
+                    }
+            }
+
+        let actual = OuterCollectRemaining.toJsonNode toWrite |> fun s -> s.ToJsonString ()
+
+        actual |> shouldEqual expected

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

@@ -41,7 +41,7 @@
   <ItemGroup>
     <PackageReference Include="ApiSurface" Version="4.1.5"/>
     <PackageReference Include="FsCheck" Version="2.16.6"/>
-    <PackageReference Include="FsUnit" Version="6.0.0"/>
+    <PackageReference Include="FsUnit" Version="6.0.1"/>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1"/>
     <PackageReference Include="NUnit" Version="4.2.2"/>
     <PackageReference Include="NUnit3TestAdapter" Version="4.6.0"/>

WoofWare.Myriad.Plugins/ArgParserGenerator.fs

@@ -1140,6 +1140,12 @@ module internal ArgParserGenerator =
                 | 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"

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/HttpClientGenerator.fs

@@ -1,5 +1,6 @@
 namespace WoofWare.Myriad.Plugins
 
+open System.IO
 open System.Net.Http
 open Fantomas.FCS.Syntax
 
@@ -12,6 +13,17 @@ type internal HttpClientGeneratorOutputSpec =
 module internal HttpClientGenerator =
     open Fantomas.FCS.Text.Range
 
+    let outputFile = FileInfo "/tmp/output.txt"
+
+    // do
+    //     use _ = File.Create outputFile.FullName
+    //     ()
+
+    let log (line : string) =
+        // use w = outputFile.AppendText ()
+        // w.WriteLine line
+        ()
+
     [<RequireQualifiedAccess>]
     type PathSpec =
         | Verbatim of string
@@ -60,6 +72,9 @@ module internal HttpClientGenerator =
             BaseAddress : SynExpr option
             BasePath : SynExpr option
             Accessibility : SynAccess option
+            /// Headers which apply *only* to this endpoint.
+            /// For example, SynConst "Authorization" and SynConst "token BLAH".
+            Headers : (SynExpr * SynExpr) list
         }
 
     let httpMethodString (m : HttpMethod) : string =
@@ -321,15 +336,33 @@ module internal HttpClientGenerator =
                 |> SynExpr.createMatch baseAddress
                 |> SynExpr.paren
 
+            let baseAddress =
+                match info.BasePath with
+                | None -> baseAddress
+                | Some basePath ->
+                    [
+                        yield baseAddress
+
+                        yield
+                            SynExpr.applyFunction
+                                uriIdent
+                                (SynExpr.tuple
+                                    [ basePath ; SynExpr.createLongIdent [ "System" ; "UriKind" ; "Relative" ] ])
+                    ]
+                    |> SynExpr.tuple
+                    |> SynExpr.applyFunction uriIdent
+
             [
-                baseAddress
-                SynExpr.applyFunction
-                    uriIdent
-                    (SynExpr.tuple
-                        [
-                            requestUriTrailer
-                            SynExpr.createLongIdent [ "System" ; "UriKind" ; "Relative" ]
-                        ])
+                yield baseAddress
+
+                yield
+                    SynExpr.applyFunction
+                        uriIdent
+                        (SynExpr.tuple
+                            [
+                                requestUriTrailer
+                                SynExpr.createLongIdent [ "System" ; "UriKind" ; "Relative" ]
+                            ])
             ]
             |> SynExpr.tuple
             |> SynExpr.applyFunction uriIdent
@@ -404,14 +437,54 @@ module internal HttpClientGenerator =
                     retType
                     (SynExpr.createIdent "jsonNode")
 
+        let contentTypeHeader, memberHeaders =
+            info.Headers
+            |> List.partition (fun (headerName, headerValue) ->
+                match headerName |> SynExpr.stripOptionalParen with
+                | SynExpr.Const (SynConst.String ("Content-Type", _, _), _) -> true
+                | _ -> false
+            )
+
+        let contentTypeHeader =
+            match contentTypeHeader with
+            | [] -> None
+            | [ _, ct ] -> Some (SynExpr.stripOptionalParen ct)
+            | _ -> failwith "Unexpectedly got multiple Content-Type headers"
+
+        let createStringContent (contents : SynExpr) =
+            SynExpr.createNew
+                (SynType.createLongIdent' [ "System" ; "Net" ; "Http" ; "StringContent" ])
+                (SynExpr.tupleNoParen
+                    [
+                        yield contents
+                        match contentTypeHeader with
+                        | None -> ()
+                        | Some ch ->
+                            yield SynExpr.createNull ()
+                            // Sigh, Gitea in particular passes "json" here
+                            match ch with
+                            | SynExpr.Const (SynConst.String ("json", _, _), _) ->
+                                yield SynExpr.CreateConst "application/json"
+                            | SynExpr.Const (SynConst.String ("html", _, _), _) -> yield SynExpr.CreateConst "text/html"
+                            | _ -> yield ch
+                    ])
+
         let handleBodyParams =
             match bodyParam with
             | None -> []
             | Some (bodyParamType, bodyParamName) ->
                 match bodyParamType with
-                | BodyParamMethods.StreamContent
-                | BodyParamMethods.ByteArrayContent
                 | BodyParamMethods.StringContent ->
+                    [
+                        Let ("queryParams", createStringContent (SynExpr.createIdent' bodyParamName))
+                        Do (
+                            SynExpr.assign
+                                (SynLongIdent.createS' [ "httpMessage" ; "Content" ])
+                                (SynExpr.createIdent "queryParams")
+                        )
+                    ]
+                | BodyParamMethods.StreamContent
+                | BodyParamMethods.ByteArrayContent ->
                     [
                         Let (
                             "queryParams",
@@ -438,22 +511,22 @@ module internal HttpClientGenerator =
                     [
                         Let (
                             "queryParams",
-                            SynExpr.createNew
-                                (SynType.createLongIdent' [ "System" ; "Net" ; "Http" ; "StringContent" ])
-                                (SynExpr.createIdent' bodyParamName
-                                 |> SynExpr.pipeThroughFunction (fst (JsonSerializeGenerator.serializeNode ty))
-                                 |> SynExpr.pipeThroughFunction (
-                                     SynExpr.createLambda
-                                         "node"
-                                         (SynExpr.ifThenElse
-                                             (SynExpr.applyFunction
-                                                 (SynExpr.createIdent "isNull")
-                                                 (SynExpr.createIdent "node"))
-                                             (SynExpr.applyFunction
-                                                 (SynExpr.createLongIdent [ "node" ; "ToJsonString" ])
-                                                 (SynExpr.CreateConst ()))
-                                             (SynExpr.CreateConst "null"))
-                                 ))
+                            createStringContent (
+                                SynExpr.createIdent' bodyParamName
+                                |> SynExpr.pipeThroughFunction (fst (JsonSerializeGenerator.serializeNode ty))
+                                |> SynExpr.pipeThroughFunction (
+                                    SynExpr.createLambda
+                                        "node"
+                                        (SynExpr.ifThenElse
+                                            (SynExpr.applyFunction
+                                                (SynExpr.createIdent "isNull")
+                                                (SynExpr.createIdent "node"))
+                                            (SynExpr.applyFunction
+                                                (SynExpr.createLongIdent [ "node" ; "ToJsonString" ])
+                                                (SynExpr.CreateConst ()))
+                                            (SynExpr.CreateConst "null"))
+                                )
+                            )
                         )
                         Do (
                             SynExpr.assign
@@ -522,6 +595,16 @@ module internal HttpClientGenerator =
                     |> Do
                 )
 
+            let setMemberHeaders =
+                memberHeaders
+                |> List.map (fun (headerName, headerValue) ->
+                    // Best-effort: assume this is a message header.
+                    SynExpr.applyFunction
+                        (SynExpr.createLongIdent [ "httpMessage" ; "Headers" ; "Add" ])
+                        (SynExpr.tuple [ headerName ; headerValue ])
+                    |> Do
+                )
+
             [
                 yield LetBang ("ct", SynExpr.createLongIdent [ "Async" ; "CancellationToken" ])
                 yield Let ("uri", requestUri)
@@ -537,6 +620,7 @@ module internal HttpClientGenerator =
 
                 yield! setVariableHeaders
                 yield! setConstantHeaders
+                yield! setMemberHeaders
 
                 yield
                     LetBang (
@@ -563,6 +647,9 @@ module internal HttpClientGenerator =
                     yield jsonNode
                 | String -> yield responseString
                 | Stream -> yield responseStream
+                | Unit ->
+                    // What we're returning doesn't depend on the content, so don't bother!
+                    ()
                 | _ ->
                     yield responseStream
                     yield jsonNode
@@ -647,6 +734,15 @@ module internal HttpClientGenerator =
             | _ -> None
         )
 
+    let insertTrailingSlash (path : SynExpr) : SynExpr =
+        match path |> SynExpr.stripOptionalParen with
+        | SynExpr.Const (SynConst.String (s, _, _), _) ->
+            if s.EndsWith '/' then
+                path
+            else
+                SynExpr.CreateConst (s + "/")
+        | _ -> SynExpr.plus (SynExpr.paren path) (SynExpr.CreateConst "/")
+
     let createModule
         (opens : SynOpenDeclTarget list)
         (ns : LongIdent)
@@ -676,8 +772,17 @@ module internal HttpClientGenerator =
                         "Expected constant header parameters to be of the form [<Header (key, value)>], but got more than two args"
             )
 
-        let baseAddress = extractBaseAddress interfaceType.Attributes
-        let basePath = extractBasePath interfaceType.Attributes
+        let baseAddress =
+            extractBaseAddress interfaceType.Attributes
+            // We artificially insert a trailing slash because this is almost certainly
+            // not meant to be an endpoint itself.
+            |> Option.map insertTrailingSlash
+
+        let basePath =
+            extractBasePath interfaceType.Attributes
+            // We artificially insert a trailing slash because this is almost certainly
+            // not meant to be an endpoint itself.
+            |> Option.map insertTrailingSlash
 
         let properties =
             interfaceType.Properties
@@ -705,6 +810,16 @@ module internal HttpClientGenerator =
             |> List.map (fun mem ->
                 let httpMethod, url = extractHttpInformation mem.Attributes
 
+                let specificHeaders =
+                    extractHeaderInformation mem.Attributes
+                    |> List.map (fun l ->
+                        match l with
+                        | [ x ; y ] -> x, y
+                        | _ ->
+                            failwith
+                                $"Expected Header attribute on member %s{mem.Identifier.idText} to have exactly two arguments."
+                    )
+
                 let shouldEnsureSuccess = not (shouldAllowAnyStatusCode mem.Attributes)
 
                 let returnType =
@@ -745,6 +860,7 @@ module internal HttpClientGenerator =
                     BaseAddress = baseAddress
                     BasePath = basePath
                     Accessibility = mem.Accessibility
+                    Headers = specificHeaders
                 }
             )
             |> List.map (constructMember constantHeaders properties)

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/JsonParseGenerator.fs

@@ -59,7 +59,7 @@ module internal JsonParseGenerator =
         | None -> node
         | Some propertyName -> assertNotNull propertyName node
         |> SynExpr.callMethod "AsValue"
-        |> SynExpr.callGenericMethod "GetValue" typeName
+        |> SynExpr.callGenericMethod (SynLongIdent.createS "GetValue") [ SynType.createLongIdent typeName ]
 
     /// {node}.AsObject()
     /// If `propertyName` is Some, uses `assertNotNull {node}` instead of `{node}`.
@@ -279,6 +279,8 @@ module internal JsonParseGenerator =
         | Measure (_measure, primType) ->
             parseNumberType options propertyName node primType
             |> SynExpr.pipeThroughFunction (Measure.getLanguagePrimitivesMeasure primType)
+        | JsonNode -> node
+        | Unit -> SynExpr.CreateConst ()
         | _ ->
             // Let's just hope that we've also got our own type annotation!
             let typeName =
@@ -375,9 +377,9 @@ module internal JsonParseGenerator =
         )
 
     let createRecordMaker (spec : JsonParseOutputSpec) (fields : SynFieldData<Ident> list) =
-        let assignments =
+        let propertyFields =
             fields
-            |> List.mapi (fun i fieldData ->
+            |> List.map (fun fieldData ->
                 let propertyNameAttr =
                     fieldData.Attrs
                     |> List.tryFind (fun attr ->
@@ -385,7 +387,12 @@ module internal JsonParseGenerator =
                             .EndsWith ("JsonPropertyName", StringComparison.Ordinal)
                     )
 
-                let options = getParseOptions fieldData.Attrs
+                let extensionDataAttr =
+                    fieldData.Attrs
+                    |> List.tryFind (fun attr ->
+                        (SynLongIdent.toString attr.TypeName)
+                            .EndsWith ("JsonExtensionData", StringComparison.Ordinal)
+                    )
 
                 let propertyName =
                     match propertyNameAttr with
@@ -401,8 +408,77 @@ module internal JsonParseGenerator =
                         sb.ToString () |> SynExpr.CreateConst
                     | Some name -> name.ArgExpr
 
+                propertyName, extensionDataAttr
+            )
+
+        let namedPropertyFields =
+            propertyFields
+            |> List.choose (fun (name, extension) ->
+                match extension with
+                | Some _ -> None
+                | None -> Some name
+            )
+
+        let isNamedPropertyField =
+            match namedPropertyFields with
+            | [] -> SynExpr.CreateConst false
+            | _ ->
+                namedPropertyFields
+                |> List.map (fun fieldName -> SynExpr.equals (SynExpr.createIdent "key") fieldName)
+                |> List.reduce SynExpr.booleanOr
+
+        let assignments =
+            List.zip fields propertyFields
+            |> List.mapi (fun i (fieldData, (propertyName, extensionDataAttr)) ->
+                let options = getParseOptions fieldData.Attrs
+
+                let accIdent = Ident.create $"arg_%i{i}"
+
+                match extensionDataAttr with
+                | Some _ ->
+                    // Can't go through the usual parse logic here, because that will try and identify the node that's
+                    // been labelled. The whole point of JsonExtensionData is that there is no such node!
+                    let valType =
+                        match fieldData.Type with
+                        | DictionaryType (String, v) -> v
+                        | _ -> failwith "Expected JsonExtensionData to be Dictionary<string, _>"
+
+                    SynExpr.ifThenElse
+                        isNamedPropertyField
+                        (SynExpr.callMethodArg
+                            "Add"
+                            (SynExpr.tuple
+                                [
+                                    SynExpr.createIdent "key"
+                                    createParseRhs options (SynExpr.createIdent "key") valType
+                                ])
+                            (SynExpr.createIdent "result"))
+                        (SynExpr.CreateConst ())
+                    |> SynExpr.createForEach
+                        (SynPat.nameWithArgs "KeyValue" [ SynPat.named "key" ; SynPat.named "value" ])
+                        (SynExpr.createIdent "node")
+                    |> fun forEach -> [ forEach ; SynExpr.createIdent "result" ]
+                    |> SynExpr.sequential
+                    |> SynExpr.createLet
+                        [
+                            SynBinding.basic
+                                [ Ident.create "result" ]
+                                []
+                                (SynExpr.typeApp
+                                    [ SynType.string ; valType ]
+                                    (SynExpr.createLongIdent [ "System" ; "Collections" ; "Generic" ; "Dictionary" ])
+                                 |> SynExpr.applyTo (SynExpr.CreateConst ()))
+
+                            SynBinding.basic
+                                [ Ident.create "node" ]
+                                []
+                                (SynExpr.createIdent "node" |> SynExpr.callMethod "AsObject")
+                        ]
+                    |> SynBinding.basic [ accIdent ] []
+                | None ->
+
                 createParseRhs options propertyName fieldData.Type
-                |> SynBinding.basic [ Ident.create $"arg_%i{i}" ] []
+                |> SynBinding.basic [ accIdent ] []
             )
 
         let finalConstruction =
@@ -483,9 +559,7 @@ module internal JsonParseGenerator =
                 |> SynExpr.index property
                 |> assertNotNull property
                 |> SynExpr.pipeThroughFunction (
-                    SynExpr.createLambda
-                        "v"
-                        (SynExpr.callGenericMethod "GetValue" [ Ident.create "string" ] (SynExpr.createIdent "v"))
+                    SynExpr.createLambda "v" (SynExpr.callGenericMethod' "GetValue" "string" (SynExpr.createIdent "v"))
                 )
                 |> SynBinding.basic [ Ident.create "ty" ] []
             ]

WoofWare.Myriad.Plugins/JsonSerializeGenerator.fs

@@ -146,6 +146,13 @@ module internal JsonSerializeGenerator =
                 ]
             |> SynExpr.createLambda "field"
             |> fun e -> e, false
+        | JsonNode -> SynExpr.createIdent "id", true
+        | Unit ->
+            SynExpr.createLambda
+                "value"
+                (SynExpr.createLongIdent [ "System" ; "Text" ; "Json" ; "Nodes" ; "JsonObject" ]
+                 |> SynExpr.applyTo (SynExpr.CreateConst ())),
+            false
         | _ ->
             // {type}.toJsonNode
             let typeName =
@@ -187,6 +194,14 @@ module internal JsonSerializeGenerator =
             sb.ToString () |> SynExpr.CreateConst
         | Some name -> name.ArgExpr
 
+    let getIsJsonExtension (attrs : SynAttribute list) : bool =
+        attrs
+        |> List.tryFind (fun attr ->
+            (SynLongIdent.toString attr.TypeName)
+                .EndsWith ("JsonExtensionData", StringComparison.Ordinal)
+        )
+        |> Option.isSome
+
     /// `populateNode` will be inserted before we return the `node` variable.
     ///
     /// That is, we give you access to a `JsonObject` called `node`,
@@ -256,7 +271,31 @@ module internal JsonSerializeGenerator =
         fields
         |> List.map (fun fieldData ->
             let propertyName = getPropertyName fieldData.Ident fieldData.Attrs
-            createSerializeRhsRecord propertyName fieldData.Ident fieldData.Type
+            let isJsonExtension = getIsJsonExtension fieldData.Attrs
+
+            if isJsonExtension then
+                let valType =
+                    match fieldData.Type with
+                    | DictionaryType (String, v) -> v
+                    | _ -> failwith "Expected JsonExtensionData to be a Dictionary<string, something>"
+
+                let serialise = fst (serializeNode valType)
+
+                SynExpr.createIdent "node"
+                |> SynExpr.callMethodArg
+                    "Add"
+                    (SynExpr.tuple
+                        [
+                            SynExpr.createIdent "key"
+                            SynExpr.applyFunction serialise (SynExpr.createIdent "value")
+                        ])
+                |> SynExpr.createForEach
+                    (SynPat.identWithArgs
+                        [ Ident.create "KeyValue" ]
+                        (SynArgPats.create [ SynPat.named "key" ; SynPat.named "value" ]))
+                    (SynExpr.createLongIdent' [ Ident.create "input" ; fieldData.Ident ])
+            else
+                createSerializeRhsRecord propertyName fieldData.Ident fieldData.Type
         )
         |> SynExpr.sequential
         |> fun expr -> SynExpr.Do (expr, range0)

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 +10,54 @@ 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'"
+        | "private" -> create "private'"
+        | _ ->
+
+        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/SynExpr.fs

@@ -85,6 +85,11 @@ module internal SynExpr =
         SynExpr.CreateAppInfix (SynExpr.CreateLongIdent SynLongIdent.booleanAnd, a)
         |> applyTo b
 
+    /// {a} || {b}
+    let booleanOr (a : SynExpr) (b : SynExpr) =
+        SynExpr.CreateAppInfix (SynExpr.CreateLongIdent SynLongIdent.booleanOr, a)
+        |> applyTo b
+
     /// {a} + {b}
     let plus (a : SynExpr) (b : SynExpr) =
         SynExpr.CreateAppInfix (
@@ -136,16 +141,15 @@ module internal SynExpr =
     let typeApp (types : SynType list) (operand : SynExpr) =
         SynExpr.TypeApp (operand, range0, types, List.replicate (types.Length - 1) range0, Some range0, range0, range0)
 
-    let callGenericMethod (meth : string) (ty : LongIdent) (obj : SynExpr) : SynExpr =
-        SynExpr.DotGet (obj, range0, SynLongIdent.createS meth, range0)
-        |> typeApp [ SynType.LongIdent (SynLongIdent.create ty) ]
+    /// {obj}.{meth}<types,...>()
+    let callGenericMethod (meth : SynLongIdent) (types : SynType list) (obj : SynExpr) : SynExpr =
+        SynExpr.DotGet (obj, range0, meth, range0)
+        |> typeApp types
         |> applyTo (SynExpr.CreateConst ())
 
     /// {obj}.{meth}<ty>()
     let callGenericMethod' (meth : string) (ty : string) (obj : SynExpr) : SynExpr =
-        SynExpr.DotGet (obj, range0, SynLongIdent.createS meth, range0)
-        |> typeApp [ SynType.createLongIdent' [ ty ] ]
-        |> applyTo (SynExpr.CreateConst ())
+        callGenericMethod (SynLongIdent.createS meth) [ SynType.createLongIdent' [ ty ] ] obj
 
     let inline index (property : SynExpr) (obj : SynExpr) : SynExpr =
         SynExpr.DotIndexedGet (obj, property, range0, range0)
@@ -237,6 +241,8 @@ module internal SynExpr =
     let inline createLet (bindings : SynBinding list) (body : SynExpr) : SynExpr =
         SynExpr.LetOrUse (false, false, bindings, body, range0, SynExprLetOrUseTrivia.empty)
 
+    let inline createDo (body : SynExpr) : SynExpr = SynExpr.Do (body, range0)
+
     let inline createMatch (matchOn : SynExpr) (cases : SynMatchClause list) : SynExpr =
         SynExpr.Match (
             DebugPointAtBinding.Yes range0,

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/SynLongIdent.fs

@@ -36,6 +36,9 @@ module internal SynLongIdent =
     let booleanAnd =
         SynLongIdent.SynLongIdent ([ Ident.create "op_BooleanAnd" ], [], [ Some (IdentTrivia.OriginalNotation "&&") ])
 
+    let booleanOr =
+        SynLongIdent.SynLongIdent ([ Ident.create "op_BooleanOr" ], [], [ Some (IdentTrivia.OriginalNotation "||") ])
+
     let pipe =
         SynLongIdent.SynLongIdent ([ Ident.create "op_PipeRight" ], [], [ Some (IdentTrivia.OriginalNotation "|>") ])
 

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

@@ -181,6 +181,29 @@ module internal SynTypePatterns =
                        _) -> Some (ident, outer)
         | _ -> None
 
+    let (|JsonNode|_|) (fieldType : SynType) : unit option =
+        match fieldType with
+        | SynType.LongIdent (SynLongIdent.SynLongIdent (ident, _, _)) ->
+            match ident |> List.map (fun i -> i.idText) with
+            | [ "System" ; "Text" ; "Json" ; "Nodes" ; "JsonNode" ]
+            | [ "Text" ; "Json" ; "Nodes" ; "JsonNode" ]
+            | [ "Json" ; "Nodes" ; "JsonNode" ]
+            | [ "Nodes" ; "JsonNode" ]
+            | [ "JsonNode" ] -> Some ()
+            | _ -> None
+        | _ -> None
+
+    let (|Unit|_|) (fieldType : SynType) : unit option =
+        match fieldType with
+        | SynType.LongIdent (SynLongIdent.SynLongIdent (ident, _, _)) ->
+            match ident |> List.map (fun i -> i.idText.ToLowerInvariant ()) with
+            | [ "microsoft" ; "fsharp" ; "core" ; "unit" ]
+            | [ "fsharp" ; "core" ; "unit" ]
+            | [ "core" ; "unit" ]
+            | [ "unit" ] -> Some ()
+            | _ -> None
+        | _ -> None
+
     let (|DateOnly|_|) (fieldType : SynType) =
         match fieldType with
         | SynType.LongIdent (SynLongIdent.SynLongIdent (ident, _, _)) ->
@@ -267,6 +290,8 @@ 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 +308,17 @@ 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 +335,54 @@ 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" />

WoofWare.Myriad.Plugins/version.json

@@ -1,5 +1,5 @@
 {
-  "version": "2.3",
+  "version": "3.0",
   "publicReleaseRefSpec": [
     "^refs/heads/main$"
   ],

nix/deps.nix

@@ -8,8 +8,8 @@
   })
   (fetchNuGet {
     pname = "fantomas";
-    version = "6.3.12";
-    hash = "sha256-LFZn2cO72FlsmLI0vTLz52Bn4XBeGILTOr8rz/EuXeg=";
+    version = "6.3.15";
+    hash = "sha256-Gjw7MxjUNckMWSfnOye4UTe5fZWnor6RHCls3PNsuG8=";
   })
   (fetchNuGet {
     pname = "Fantomas.Core";
@@ -48,8 +48,8 @@
   })
   (fetchNuGet {
     pname = "FsUnit";
-    version = "6.0.0";
-    hash = "sha256-q87WQf6MqGhzvaQ7WkkUlCdoE94DY0CD5PaXEj64A6M=";
+    version = "6.0.1";
+    hash = "sha256-vka/aAgWhDCl5tu+kgO7GtSaHOOvlSaWxG+tExwGXpI=";
   })
   (fetchNuGet {
     pname = "Microsoft.AspNetCore.App.Ref";