union definitions

compiler/NubType.cs

@@ -111,6 +111,30 @@ public class NubTypeStruct : NubType
     public override string ToString() => $"struct {Module}::{Name}";
 }
 
+public class NubTypeEnum : NubType
+{
+    private static readonly Dictionary<(string Module, string Name), NubTypeEnum> Cache = new();
+
+    public static NubTypeEnum Get(string module, string name)
+    {
+        if (!Cache.TryGetValue((module, name), out var enumType))
+            Cache[(module, name)] = enumType = new NubTypeEnum(module, name);
+
+        return enumType;
+    }
+
+    private NubTypeEnum(string module, string name)
+    {
+        Module = module;
+        Name = name;
+    }
+
+    public string Module { get; }
+    public string Name { get; }
+
+    public override string ToString() => $"enum {Module}::{Name}";
+}
+
 public class NubTypePointer : NubType
 {
     private static readonly Dictionary<NubType, NubTypePointer> Cache = new();
@@ -172,8 +196,6 @@ public class TypeEncoder
     {
     }
 
-    private Dictionary<NubTypeStruct, Definition> structDefinitions = new();
-
     private string EncodeRoot(NubType type)
     {
         var sb = new StringBuilder();
@@ -223,6 +245,14 @@ public class TypeEncoder
                 sb.Append(')');
                 break;
 
+            case NubTypeEnum st:
+                sb.Append("E(");
+                sb.Append(st.Module);
+                sb.Append(':');
+                sb.Append(st.Name);
+                sb.Append(')');
+                break;
+
             case NubTypeFunc fn:
                 sb.Append("F(");
                 for (int i = 0; i < fn.Parameters.Count; i++)
@@ -273,6 +303,7 @@ public class TypeDecoder
             'P' => DecodePointer(),
             'F' => DecodeFunc(),
             'T' => DecodeStruct(),
+            'E' => DecodeEnum(),
             _ => throw new Exception($"'{start}' is not a valid start to a type")
         };
     }
@@ -333,6 +364,25 @@ public class TypeDecoder
         return NubTypeStruct.Get(module, name);
     }
 
+    private NubTypeEnum DecodeEnum()
+    {
+        var sb = new StringBuilder();
+
+        Expect('(');
+        while (!TryExpect(':'))
+            sb.Append(Consume());
+
+        var module = sb.ToString();
+        sb.Clear();
+
+        while (!TryExpect(')'))
+            sb.Append(Consume());
+
+        var name = sb.ToString();
+
+        return NubTypeEnum.Get(module, name);
+    }
+
     private bool TryPeek(out char c)
     {
         if (index >= encoded.Length)