Reduce duplication (#149)

WoofWare.Myriad.Plugins/SynExpr/SynUnionCase.fs

@@ -0,0 +1,32 @@
+namespace WoofWare.Myriad.Plugins
+
+open Fantomas.FCS.Syntax
+
+type internal UnionCase<'Ident> =
+    {
+        Fields : SynFieldData<'Ident> list
+        Attrs : SynAttribute list
+        Ident : Ident
+    }
+
+[<RequireQualifiedAccess>]
+module internal SynUnionCase =
+    let extract (SynUnionCase (attrs, id, caseType, _, _, _, _)) : UnionCase<Ident option> =
+        match caseType with
+        | SynUnionCaseKind.FullType _ -> failwith "WoofWare.Myriad does not support FullType union cases."
+        | SynUnionCaseKind.Fields fields ->
+
+        let fields = fields |> List.map SynField.extract
+
+        let id =
+            match id with
+            | SynIdent.SynIdent (ident, _) -> ident
+
+        // As far as I can tell, there's no way to get any attributes here? :shrug:
+        let attrs = attrs |> List.collect (fun l -> l.Attributes)
+
+        {
+            Fields = fields
+            Attrs = attrs
+            Ident = id
+        }