Pull out general changes from ArgParser PR (#217)

ConsumePlugin/ConsumePlugin.fsproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
     <IsPackable>false</IsPackable>
+    <OtherFlags>--reflectionfree $(OtherFlags)</OtherFlags>
   </PropertyGroup>
   <ItemGroup>
     <MyriadSdkGenerator Include="$(MSBuildThisFileDirectory)..\WoofWare.Myriad.Plugins\bin\$(Configuration)\net6.0\WoofWare.Myriad.Plugins.dll"/>
@@ -56,9 +57,8 @@
   <ItemGroup>
     <PackageReference Include="RestEase" Version="1.6.4"/>
     <ProjectReference Include="..\WoofWare.Myriad.Plugins.Attributes\WoofWare.Myriad.Plugins.Attributes.fsproj" />
-    <ProjectReference Include="..\WoofWare.Myriad.Plugins\WoofWare.Myriad.Plugins.fsproj"/>
-    <PackageReference Include="Myriad.Sdk" Version="0.8.3"/>
-    <PackageReference Include="Myriad.Core" Version="0.8.3"/>
+    <ProjectReference Include="..\WoofWare.Myriad.Plugins\WoofWare.Myriad.Plugins.fsproj" PrivateAssets="all" />
+    <PackageReference Include="Myriad.Sdk" Version="0.8.3" PrivateAssets="all" />
   </ItemGroup>
 
 </Project>

ConsumePlugin/FSharpForFunAndProfitCata.fs

@@ -30,6 +30,12 @@ type ChocolateType =
     | Milk
     | SeventyPercent
 
+    override this.ToString () =
+        match this with
+        | ChocolateType.Dark -> "Dark"
+        | ChocolateType.Milk -> "Milk"
+        | ChocolateType.SeventyPercent -> "SeventyPercent"
+
 type Chocolate =
     {
         chocType : ChocolateType
@@ -43,6 +49,12 @@ type WrappingPaperStyle =
     | HappyHolidays
     | SolidColor
 
+    override this.ToString () =
+        match this with
+        | WrappingPaperStyle.HappyBirthday -> "HappyBirthday"
+        | WrappingPaperStyle.HappyHolidays -> "HappyHolidays"
+        | WrappingPaperStyle.SolidColor -> "SolidColor"
+
 [<CreateCatamorphism "GiftCata">]
 type Gift =
     | Book of Book

ConsumePlugin/RecordFile.fs

@@ -1,9 +1,5 @@
 namespace ConsumePlugin
 
-type ParseState =
-    | AwaitingKey
-    | AwaitingValue of string
-
 /// My whatnot
 [<WoofWare.Myriad.Plugins.RemoveOptions>]
 type RecordType =

WoofWare.Myriad.Plugins.Test/TestCataGenerator/TestGift.fs

@@ -43,7 +43,7 @@ module TestGift =
                     member _.WithACard g message =
                         $"%s{g} with a card saying '%s{message}'"
 
-                    member _.Wrapped g paper = $"%s{g} wrapped in %A{paper} paper"
+                    member _.Wrapped g paper = $"%s{g} wrapped in %O{paper} paper"
                 }
         }
 

WoofWare.Myriad.Plugins/AstHelper.fs

@@ -62,13 +62,46 @@ type internal InterfaceType =
 type internal RecordType =
     {
         Name : Ident
-        Fields : SynField seq
+        Fields : SynField list
+        /// Any additional members which are not record fields.
         Members : SynMemberDefns option
         XmlDoc : PreXmlDoc option
         Generics : SynTyparDecls option
         Accessibility : SynAccess option
+        Attributes : SynAttribute list
     }
 
+    /// Parse from the AST.
+    static member OfRecord (record : SynTypeDefn) : RecordType =
+        let sci, sdr, smd, smdo =
+            match record with
+            | SynTypeDefn.SynTypeDefn (sci, sdr, smd, smdo, _, _) -> sci, sdr, smd, smdo
+
+        let synAccessOption, recordFields =
+            match sdr with
+            | SynTypeDefnRepr.Simple (SynTypeDefnSimpleRepr.Record (sa, fields, _), _) -> sa, fields
+            | _ -> failwith $"expected a record; got: %+A{record}"
+
+        match sci with
+        | SynComponentInfo.SynComponentInfo (attrs, typars, _, longId, doc, _, access, _) ->
+            if access <> synAccessOption then
+                failwith
+                    $"TODO what's happened, two different accessibility modifiers: %O{access} and %O{synAccessOption}"
+
+            match smdo with
+            | Some v -> failwith $"TODO what's happened, got a synMemberDefn of %O{v}"
+            | None -> ()
+
+            {
+                Name = List.last longId
+                Fields = recordFields
+                Members = if smd.IsEmpty then None else Some smd
+                XmlDoc = if doc.IsEmpty then None else Some doc
+                Generics = typars
+                Accessibility = synAccessOption
+                Attributes = attrs |> List.collect (fun l -> l.Attributes)
+            }
+
 /// Anything that is part of an ADT.
 /// A record is a product of stuff; this type represents one of those stuffs.
 type internal AdtNode =
@@ -101,10 +134,10 @@ module internal AstHelper =
         | SynTypeDefnRepr.Simple (SynTypeDefnSimpleRepr.Enum _, _) -> true
         | _ -> false
 
-    let instantiateRecord (fields : (RecordFieldName * SynExpr option) list) : SynExpr =
+    let instantiateRecord (fields : (SynLongIdent * SynExpr) list) : SynExpr =
         let fields =
             fields
-            |> List.map (fun (rfn, synExpr) -> SynExprRecordField (rfn, Some range0, synExpr, None))
+            |> List.map (fun (rfn, synExpr) -> SynExprRecordField ((rfn, true), Some range0, Some synExpr, None))
 
         SynExpr.Record (None, None, fields, range0)
 

WoofWare.Myriad.Plugins/CataGenerator.fs

@@ -1100,7 +1100,7 @@ module internal CataGenerator =
         let moduleName = parentName + "Cata" |> Ident.create
 
         let modInfo =
-            SynComponentInfo.create (parentName + "Cata" |> Ident.create)
+            SynComponentInfo.create moduleName
             |> SynComponentInfo.withDocString (
                 PreXmlDoc.Create $" Methods to perform a catamorphism over the type %s{parentName}"
             )

WoofWare.Myriad.Plugins/HttpClientGenerator.fs

@@ -257,11 +257,7 @@ module internal HttpClientGenerator =
                     | Some id -> id
 
                 let urlSeparator =
-                    // apparent Myriad bug: `IndexOf '?'` gets formatted as `IndexOf ?` which is clearly wrong
-                    let questionMark =
-                        SynExpr.CreateConst 63
-                        |> SynExpr.applyFunction (SynExpr.createIdent "char")
-                        |> SynExpr.paren
+                    let questionMark = SynExpr.CreateConst '?'
 
                     let containsQuestion =
                         info.UrlTemplate
@@ -425,21 +421,17 @@ module internal HttpClientGenerator =
                                 (SynExpr.createIdent' bodyParamName)
                         )
                         Do (
-                            SynExpr.LongIdentSet (
-                                SynLongIdent.createS' [ "httpMessage" ; "Content" ],
-                                SynExpr.createIdent "queryParams",
-                                range0
-                            )
+                            SynExpr.assign
+                                (SynLongIdent.createS' [ "httpMessage" ; "Content" ])
+                                (SynExpr.createIdent "queryParams")
                         )
                     ]
                 | BodyParamMethods.HttpContent ->
                     [
                         Do (
-                            SynExpr.LongIdentSet (
-                                SynLongIdent.createS' [ "httpMessage" ; "Content" ],
-                                SynExpr.createIdent' bodyParamName,
-                                range0
-                            )
+                            SynExpr.assign
+                                (SynLongIdent.createS' [ "httpMessage" ; "Content" ])
+                                (SynExpr.createIdent' bodyParamName)
                         )
                     ]
                 | BodyParamMethods.Serialise ty ->
@@ -464,11 +456,9 @@ module internal HttpClientGenerator =
                                  ))
                         )
                         Do (
-                            SynExpr.LongIdentSet (
-                                SynLongIdent.createS' [ "httpMessage" ; "Content" ],
-                                SynExpr.createIdent "queryParams",
-                                range0
-                            )
+                            SynExpr.assign
+                                (SynLongIdent.createS' [ "httpMessage" ; "Content" ])
+                                (SynExpr.createIdent "queryParams")
                         )
                     ]
 

WoofWare.Myriad.Plugins/InterfaceMockGenerator.fs

@@ -71,13 +71,13 @@ module internal InterfaceMockGenerator =
                 if inherits.Contains KnownInheritance.IDisposable then
                     let unitFun = SynExpr.createThunk (SynExpr.CreateConst ())
 
-                    [ (SynLongIdent.createS "Dispose", true), Some unitFun ]
+                    [ SynLongIdent.createS "Dispose", unitFun ]
                 else
                     []
 
             let nonExtras =
                 fields
-                |> List.map (fun field -> (SynLongIdent.createI (getName field), true), Some (failwithFun field))
+                |> List.map (fun field -> SynLongIdent.createI (getName field), failwithFun field)
 
             extras @ nonExtras
 
@@ -213,6 +213,7 @@ module internal InterfaceMockGenerator =
                 XmlDoc = Some xmlDoc
                 Generics = interfaceType.Generics
                 Accessibility = Some access
+                Attributes = []
             }
 
         let typeDecl = AstHelper.defineRecordType record

WoofWare.Myriad.Plugins/JsonParseGenerator.fs

@@ -407,9 +407,7 @@ module internal JsonParseGenerator =
 
         let finalConstruction =
             fields
-            |> List.mapi (fun i fieldData ->
-                (SynLongIdent.createI fieldData.Ident, true), Some (SynExpr.createIdent $"arg_%i{i}")
-            )
+            |> List.mapi (fun i fieldData -> SynLongIdent.createI fieldData.Ident, SynExpr.createIdent $"arg_%i{i}")
             |> AstHelper.instantiateRecord
 
         (finalConstruction, assignments)

WoofWare.Myriad.Plugins/RemoveOptionsGenerator.fs

@@ -42,6 +42,7 @@ module internal RemoveOptionsGenerator =
         (accessibility : SynAccess option)
         (generics : SynTyparDecls option)
         (fields : SynField list)
+        : SynModuleDecl
         =
         let fields : SynField list = fields |> List.map removeOption
         let name = Ident.create "Short"
@@ -54,6 +55,7 @@ module internal RemoveOptionsGenerator =
                 XmlDoc = xmlDoc
                 Generics = generics
                 Accessibility = accessibility
+                Attributes = []
             }
 
         let typeDecl = AstHelper.defineRecordType record
@@ -91,7 +93,7 @@ module internal RemoveOptionsGenerator =
                         )
                     | _ -> accessor
 
-                (SynLongIdent.createI fieldData.Ident, true), Some body
+                SynLongIdent.createI fieldData.Ident, body
             )
             |> AstHelper.instantiateRecord
 

WoofWare.Myriad.Plugins/SynExpr/SynAttributes.fs

@@ -0,0 +1,15 @@
+namespace WoofWare.Myriad.Plugins
+
+open Fantomas.FCS.Syntax
+open Fantomas.FCS.Text.Range
+
+[<RequireQualifiedAccess>]
+module internal SynAttributes =
+    let ofAttrs (attrs : SynAttribute list) : SynAttributes =
+        attrs
+        |> List.map (fun a ->
+            {
+                Attributes = [ a ]
+                Range = range0
+            }
+        )

WoofWare.Myriad.Plugins/SynExpr/SynBinding.fs

@@ -62,6 +62,35 @@ module internal SynBinding =
             triviaZero false
         )
 
+    let withMutability (mut : bool) (binding : SynBinding) : SynBinding =
+        match binding with
+        | SynBinding (pat, kind, inl, _, attrs, xml, valData, headPat, returnInfo, expr, range, debugPoint, trivia) ->
+            SynBinding (pat, kind, inl, mut, attrs, xml, valData, headPat, returnInfo, expr, range, debugPoint, trivia)
+
+    let withRecursion (isRec : bool) (binding : SynBinding) : SynBinding =
+        match binding with
+        | SynBinding (pat, kind, inl, mut, attrs, xml, valData, headPat, returnInfo, expr, range, debugPoint, trivia) ->
+            let trivia =
+                { trivia with
+                    LeadingKeyword =
+                        match trivia.LeadingKeyword with
+                        | SynLeadingKeyword.Let _ ->
+                            if isRec then
+                                SynLeadingKeyword.LetRec (range0, range0)
+                            else
+                                trivia.LeadingKeyword
+                        | SynLeadingKeyword.LetRec _ ->
+                            if isRec then
+                                trivia.LeadingKeyword
+                            else
+                                trivia.LeadingKeyword
+                        | existing ->
+                            failwith
+                                $"WoofWare.Myriad doesn't yet let you adjust the recursion modifier on a binding with modifier %O{existing}"
+                }
+
+            SynBinding (pat, kind, inl, mut, attrs, xml, valData, headPat, returnInfo, expr, range, debugPoint, trivia)
+
     let withAccessibility (acc : SynAccess option) (binding : SynBinding) : SynBinding =
         match binding with
         | SynBinding (_, kind, inl, mut, attrs, xml, valData, headPat, returnInfo, expr, range, debugPoint, trivia) ->

WoofWare.Myriad.Plugins/SynExpr/SynExpr.fs

@@ -13,6 +13,13 @@ module internal SynExprExtensions =
 
         static member CreateConst () : SynExpr = SynExpr.Const (SynConst.Unit, range0)
 
+        static member CreateConst (b : bool) : SynExpr = SynExpr.Const (SynConst.Bool b, range0)
+
+        static member CreateConst (c : char) : SynExpr =
+            // apparent Myriad bug: `IndexOf '?'` gets formatted as `IndexOf ?` which is clearly wrong
+            SynExpr.CreateApp (SynExpr.Ident (Ident.Create "char"), SynExpr.CreateConst (int c))
+            |> fun e -> SynExpr.Paren (e, range0, Some range0, range0)
+
         static member CreateConst (i : int32) : SynExpr =
             SynExpr.Const (SynConst.Int32 i, range0)
 
@@ -138,6 +145,14 @@ module internal SynExpr =
     let inline index (property : SynExpr) (obj : SynExpr) : SynExpr =
         SynExpr.DotIndexedGet (obj, property, range0, range0)
 
+    let inline arrayIndexRange (start : SynExpr option) (endRange : SynExpr option) (arr : SynExpr) : SynExpr =
+        SynExpr.DotIndexedGet (
+            arr,
+            (SynExpr.IndexRange (start, range0, endRange, range0, range0, range0)),
+            range0,
+            range0
+        )
+
     let inline paren (e : SynExpr) : SynExpr =
         SynExpr.Paren (e, range0, Some range0, range0)
 
@@ -202,6 +217,18 @@ module internal SynExpr =
 
         pipeThroughFunction lambda body
 
+    let inline createForEach (pat : SynPat) (enumExpr : SynExpr) (body : SynExpr) : SynExpr =
+        SynExpr.ForEach (
+            DebugPointAtFor.No,
+            DebugPointAtInOrTo.No,
+            SeqExprOnly.SeqExprOnly false,
+            true,
+            pat,
+            enumExpr,
+            body,
+            range0
+        )
+
     let inline createLet (bindings : SynBinding list) (body : SynExpr) : SynExpr =
         SynExpr.LetOrUse (false, false, bindings, body, range0, SynExprLetOrUseTrivia.empty)
 
@@ -296,9 +323,37 @@ module internal SynExpr =
 
     /// {y} > {x}
     let greaterThan (x : SynExpr) (y : SynExpr) : SynExpr =
-        SynExpr.CreateAppInfix (SynExpr.CreateLongIdent SynLongIdent.ge, y) |> applyTo x
+        SynExpr.CreateAppInfix (SynExpr.CreateLongIdent SynLongIdent.gt, y) |> applyTo x
+
+    /// {y} < {x}
+    let lessThan (x : SynExpr) (y : SynExpr) : SynExpr =
+        SynExpr.CreateAppInfix (SynExpr.CreateLongIdent SynLongIdent.lt, y) |> applyTo x
 
     /// {y} >= {x}
     let greaterThanOrEqual (x : SynExpr) (y : SynExpr) : SynExpr =
         SynExpr.CreateAppInfix (SynExpr.CreateLongIdent SynLongIdent.geq, y)
         |> applyTo x
+
+    /// {y} <= {x}
+    let lessThanOrEqual (x : SynExpr) (y : SynExpr) : SynExpr =
+        SynExpr.CreateAppInfix (SynExpr.CreateLongIdent SynLongIdent.leq, y)
+        |> applyTo x
+
+    /// {x} :: {y}
+    let listCons (x : SynExpr) (y : SynExpr) : SynExpr =
+        SynExpr.CreateAppInfix (
+            SynExpr.LongIdent (
+                false,
+                SynLongIdent.SynLongIdent (
+                    [ Ident.create "op_ColonColon" ],
+                    [],
+                    [ Some (IdentTrivia.OriginalNotation "::") ]
+                ),
+                None,
+                range0
+            ),
+            tupleNoParen [ x ; y ]
+        )
+        |> paren
+
+    let assign (lhs : SynLongIdent) (rhs : SynExpr) : SynExpr = SynExpr.LongIdentSet (lhs, rhs, range0)

WoofWare.Myriad.Plugins/SynExpr/SynLongIdent.fs

@@ -14,9 +14,19 @@ module internal SynLongIdent =
             [ Some (IdentTrivia.OriginalNotation ">=") ]
         )
 
-    let ge =
+    let leq =
+        SynLongIdent.SynLongIdent (
+            [ Ident.create "op_LessThanOrEqual" ],
+            [],
+            [ Some (IdentTrivia.OriginalNotation "<=") ]
+        )
+
+    let gt =
         SynLongIdent.SynLongIdent ([ Ident.create "op_GreaterThan" ], [], [ Some (IdentTrivia.OriginalNotation ">") ])
 
+    let lt =
+        SynLongIdent.SynLongIdent ([ Ident.create "op_LessThan" ], [], [ Some (IdentTrivia.OriginalNotation "<") ])
+
     let sub =
         SynLongIdent.SynLongIdent ([ Ident.create "op_Subtraction" ], [], [ Some (IdentTrivia.OriginalNotation "-") ])
 
@@ -70,6 +80,12 @@ module internal SynLongIdent =
         // TODO: consider Microsoft.FSharp.Option or whatever it is
         | _ -> false
 
+    let isChoice (ident : SynLongIdent) : bool =
+        match ident.LongIdent with
+        | [ i ] when System.String.Equals (i.idText, "Choice", System.StringComparison.Ordinal) -> true
+        // TODO: consider Microsoft.FSharp.Choice or whatever it is
+        | _ -> false
+
     let isNullable (ident : SynLongIdent) : bool =
         match ident.LongIdent |> List.map _.idText with
         | [ "System" ; "Nullable" ]

WoofWare.Myriad.Plugins/SynExpr/SynModuleDecl.fs

@@ -14,6 +14,8 @@ module internal SynModuleDecl =
 
     let inline createLet (binding : SynBinding) : SynModuleDecl = createLets [ binding ]
 
+    let inline createTypes (tys : SynTypeDefn list) : SynModuleDecl = SynModuleDecl.Types (tys, range0)
+
     let nestedModule (info : SynComponentInfo) (decls : SynModuleDecl list) : SynModuleDecl =
         SynModuleDecl.NestedModule (
             info,

WoofWare.Myriad.Plugins/SynExpr/SynPat.fs

@@ -33,3 +33,17 @@ module internal SynPat =
     let unit = createConst SynConst.Unit
 
     let createNull = SynPat.Null range0
+
+    let emptyList = SynPat.ArrayOrList (false, [], range0)
+
+    let listCons (lhs : SynPat) (rhs : SynPat) =
+        SynPat.ListCons (
+            lhs,
+            rhs,
+            range0,
+            {
+                ColonColonRange = range0
+            }
+        )
+
+    let emptyArray = SynPat.ArrayOrList (true, [], range0)

WoofWare.Myriad.Plugins/SynExpr/SynType.fs

@@ -1,56 +1,9 @@
 namespace WoofWare.Myriad.Plugins
 
+open System
 open Fantomas.FCS.Syntax
 open Fantomas.FCS.Text.Range
 
-[<RequireQualifiedAccess>]
-module internal SynType =
-    let rec stripOptionalParen (ty : SynType) : SynType =
-        match ty with
-        | SynType.Paren (ty, _) -> stripOptionalParen ty
-        | ty -> ty
-
-    let inline createLongIdent (ident : LongIdent) : SynType =
-        SynType.LongIdent (SynLongIdent.create ident)
-
-    let inline createLongIdent' (ident : string list) : SynType =
-        SynType.LongIdent (SynLongIdent.createS' ident)
-
-    let inline named (name : string) = createLongIdent' [ name ]
-
-    let inline app' (name : SynType) (args : SynType list) : SynType =
-        if args.IsEmpty then
-            failwith "Type cannot be applied to no arguments"
-
-        SynType.App (name, Some range0, args, List.replicate (args.Length - 1) range0, Some range0, false, range0)
-
-    let inline app (name : string) (args : SynType list) : SynType = app' (named name) args
-
-    let inline appPostfix (name : string) (arg : SynType) : SynType =
-        SynType.App (named name, None, [ arg ], [], None, true, range0)
-
-    let inline funFromDomain (domain : SynType) (range : SynType) : SynType =
-        SynType.Fun (
-            domain,
-            range,
-            range0,
-            {
-                ArrowRange = range0
-            }
-        )
-
-    let inline signatureParamOfType (ty : SynType) (name : Ident option) : SynType =
-        SynType.SignatureParameter ([], false, name, ty, range0)
-
-    let inline var (ty : SynTypar) : SynType = SynType.Var (ty, range0)
-
-    let unit : SynType = named "unit"
-    let int : SynType = named "int"
-
-    /// Given ['a1, 'a2] and 'ret, returns 'a1 -> 'a2 -> 'ret.
-    let toFun (inputs : SynType list) (ret : SynType) : SynType =
-        (ret, List.rev inputs) ||> List.fold (fun ty input -> funFromDomain input ty)
-
 [<AutoOpen>]
 module internal SynTypePatterns =
     let (|OptionType|_|) (fieldType : SynType) =
@@ -59,6 +12,11 @@ module internal SynTypePatterns =
             Some innerType
         | _ -> None
 
+    let (|ChoiceType|_|) (fieldType : SynType) =
+        match fieldType with
+        | SynType.App (SynType.LongIdent ident, _, inner, _, _, _, _) when SynLongIdent.isChoice ident -> Some inner
+        | _ -> None
+
     let (|NullableType|_|) (fieldType : SynType) =
         match fieldType with
         | SynType.App (SynType.LongIdent ident, _, [ innerType ], _, _, _, _) when SynLongIdent.isNullable ident ->
@@ -272,3 +230,169 @@ module internal SynTypePatterns =
                 | _ -> failwithf "Expected Task to be applied to exactly one arg, but got: %+A" args
             | _ -> None
         | _ -> None
+
+    let (|DirectoryInfo|_|) (fieldType : SynType) =
+        match fieldType with
+        | SynType.LongIdent (SynLongIdent.SynLongIdent (ident, _, _)) ->
+            match ident |> List.map (fun i -> i.idText) with
+            | [ "System" ; "IO" ; "DirectoryInfo" ]
+            | [ "IO" ; "DirectoryInfo" ]
+            | [ "DirectoryInfo" ] -> Some ()
+            | _ -> None
+        | _ -> None
+
+    let (|FileInfo|_|) (fieldType : SynType) =
+        match fieldType with
+        | SynType.LongIdent (SynLongIdent.SynLongIdent (ident, _, _)) ->
+            match ident |> List.map (fun i -> i.idText) with
+            | [ "System" ; "IO" ; "FileInfo" ]
+            | [ "IO" ; "FileInfo" ]
+            | [ "FileInfo" ] -> Some ()
+            | _ -> None
+        | _ -> None
+
+[<RequireQualifiedAccess>]
+module internal SynType =
+    let rec stripOptionalParen (ty : SynType) : SynType =
+        match ty with
+        | SynType.Paren (ty, _) -> stripOptionalParen ty
+        | ty -> ty
+
+    let inline createLongIdent (ident : LongIdent) : SynType =
+        SynType.LongIdent (SynLongIdent.create ident)
+
+    let inline createLongIdent' (ident : string list) : SynType =
+        SynType.LongIdent (SynLongIdent.createS' ident)
+
+    let inline named (name : string) = createLongIdent' [ name ]
+
+    let inline app' (name : SynType) (args : SynType list) : SynType =
+        if args.IsEmpty then
+            failwith "Type cannot be applied to no arguments"
+
+        SynType.App (name, Some range0, args, List.replicate (args.Length - 1) range0, Some range0, false, range0)
+
+    let inline app (name : string) (args : SynType list) : SynType = app' (named name) args
+
+    let inline appPostfix (name : string) (arg : SynType) : SynType =
+        SynType.App (named name, None, [ arg ], [], None, true, range0)
+
+    let inline appPostfix' (name : string list) (arg : SynType) : SynType =
+        SynType.App (createLongIdent' name, None, [ arg ], [], None, true, range0)
+
+    let inline funFromDomain (domain : SynType) (range : SynType) : SynType =
+        SynType.Fun (
+            domain,
+            range,
+            range0,
+            {
+                ArrowRange = range0
+            }
+        )
+
+    let inline signatureParamOfType (ty : SynType) (name : Ident option) : SynType =
+        SynType.SignatureParameter ([], false, name, ty, range0)
+
+    let inline var (ty : SynTypar) : SynType = SynType.Var (ty, range0)
+
+    let unit : SynType = named "unit"
+    let int : SynType = named "int"
+
+    let anon : SynType = SynType.Anon range0
+
+    let string : SynType = named "string"
+
+    /// Given ['a1, 'a2] and 'ret, returns 'a1 -> 'a2 -> 'ret.
+    let toFun (inputs : SynType list) (ret : SynType) : SynType =
+        (ret, List.rev inputs) ||> List.fold (fun ty input -> funFromDomain input ty)
+
+    /// Guess whether the types are equal. We err on the side of saying "no, they're different".
+    let rec provablyEqual (ty1 : SynType) (ty2 : SynType) : bool =
+        if Object.ReferenceEquals (ty1, ty2) then
+            true
+        else
+
+        match ty1 with
+        | PrimitiveType t1 ->
+            match ty2 with
+            | PrimitiveType t2 -> (t1 |> List.map _.idText) = (t2 |> List.map _.idText)
+            | _ -> false
+        | OptionType t1 ->
+            match ty2 with
+            | OptionType t2 -> provablyEqual t1 t2
+            | _ -> false
+        | NullableType t1 ->
+            match ty2 with
+            | NullableType t2 -> provablyEqual t1 t2
+            | _ -> false
+        | ChoiceType t1 ->
+            match ty2 with
+            | ChoiceType t2 ->
+                t1.Length = t2.Length
+                && List.forall (fun (a, b) -> provablyEqual a b) (List.zip t1 t2)
+            | _ -> false
+        | DictionaryType (k1, v1) ->
+            match ty2 with
+            | DictionaryType (k2, v2) -> provablyEqual k1 k2 && provablyEqual v1 v2
+            | _ -> false
+        | IDictionaryType (k1, v1) ->
+            match ty2 with
+            | IDictionaryType (k2, v2) -> provablyEqual k1 k2 && provablyEqual v1 v2
+            | _ -> false
+        | IReadOnlyDictionaryType (k1, v1) ->
+            match ty2 with
+            | IReadOnlyDictionaryType (k2, v2) -> provablyEqual k1 k2 && provablyEqual v1 v2
+            | _ -> false
+        | MapType (k1, v1) ->
+            match ty2 with
+            | MapType (k2, v2) -> provablyEqual k1 k2 && provablyEqual v1 v2
+            | _ -> false
+        | ListType t1 ->
+            match ty2 with
+            | ListType t2 -> provablyEqual t1 t2
+            | _ -> false
+        | ArrayType t1 ->
+            match ty2 with
+            | ArrayType t2 -> provablyEqual t1 t2
+            | _ -> false
+        | Task t1 ->
+            match ty2 with
+            | Task t2 -> provablyEqual t1 t2
+            | _ -> false
+        | UnitType ->
+            match ty2 with
+            | UnitType -> true
+            | _ -> false
+        | FileInfo ->
+            match ty2 with
+            | FileInfo -> true
+            | _ -> false
+        | DirectoryInfo ->
+            match ty2 with
+            | DirectoryInfo -> true
+            | _ -> false
+        | Uri ->
+            match ty2 with
+            | Uri -> true
+            | _ -> false
+        | Stream ->
+            match ty2 with
+            | Stream -> true
+            | _ -> false
+        | Guid ->
+            match ty2 with
+            | Guid -> true
+            | _ -> false
+        | BigInt ->
+            match ty2 with
+            | BigInt -> true
+            | _ -> false
+        | DateTimeOffset ->
+            match ty2 with
+            | DateTimeOffset -> true
+            | _ -> false
+        | DateOnly ->
+            match ty2 with
+            | DateOnly -> true
+            | _ -> false
+        | _ -> false

WoofWare.Myriad.Plugins/SynExpr/SynUnionCase.fs

@@ -1,6 +1,9 @@
 namespace WoofWare.Myriad.Plugins
 
 open Fantomas.FCS.Syntax
+open Fantomas.FCS.Text.Range
+open Fantomas.FCS.Xml
+open Fantomas.FCS.SyntaxTrivia
 
 type internal UnionCase<'Ident> =
     {
@@ -39,3 +42,34 @@ module internal SynUnionCase =
             Attrs = attrs
             Ident = id
         }
+
+    let create (case : UnionCase<Ident>) : SynUnionCase =
+        let fields =
+            case.Fields
+            |> List.map (fun field ->
+                SynField.SynField (
+                    SynAttributes.ofAttrs field.Attrs,
+                    false,
+                    Some field.Ident,
+                    field.Type,
+                    false,
+                    PreXmlDoc.Empty,
+                    None,
+                    range0,
+                    {
+                        LeadingKeyword = None
+                    }
+                )
+            )
+
+        SynUnionCase.SynUnionCase (
+            SynAttributes.ofAttrs case.Attrs,
+            SynIdent.SynIdent (case.Ident, None),
+            SynUnionCaseKind.Fields fields,
+            PreXmlDoc.Empty,
+            None,
+            range0,
+            {
+                BarRange = Some range0
+            }
+        )

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

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
@@ -18,7 +18,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Myriad.Core" Version="0.8.3" PrivateAssets="all"/>
+    <PackageReference Include="Myriad.Core" Version="0.8.3" />
     <!-- the lowest version allowed by Myriad.Core -->
     <PackageReference Update="FSharp.Core" Version="6.0.1" PrivateAssets="all"/>
   </ItemGroup>
@@ -26,6 +26,7 @@
   <ItemGroup>
     <Compile Include="List.fs"/>
     <Compile Include="Primitives.fs" />
+    <Compile Include="SynExpr\SynAttributes.fs" />
     <Compile Include="SynExpr\PreXmlDoc.fs" />
     <Compile Include="SynExpr\Ident.fs" />
     <Compile Include="SynExpr\SynLongIdent.fs" />