feat: Adds AnyVal type

Sources/Haystack/Dict.swift

@@ -105,12 +105,8 @@ public extension Dict {
                     )
                 }
             } else {
-                typeLoop: for type in ValType.allCases {
-                    if let val = try? container.decode(type.type, forKey: key) {
-                        elements[key.stringValue] = val
-                        break typeLoop
-                    }
-                }
+                let val = try container.decode(AnyVal.self, forKey: key)
+                elements[key.stringValue] = val.val
             }
         }
         self.elements = elements

Sources/Haystack/List.swift

@@ -42,12 +42,8 @@ public extension List {
 
         var elements = [any Val]()
         containerLoop: while !container.isAtEnd {
-            typeLoop: for type in ValType.allCases {
-                if let val = try? container.decode(type.type) {
-                    elements.append(val)
-                    break typeLoop
-                }
-            }
+            let val = try container.decode(AnyVal.self)
+            elements.append(val.val)
         }
         self.elements = elements
     }

Sources/Haystack/Utils/AnyVal.swift

@@ -0,0 +1,55 @@
+/// This type-erased struct centralizes general operations that may act across different Haystack value types unknown
+/// at compile time like equality, decoding, and comparison.
+struct AnyVal: Codable, Hashable, Sendable {
+    /// The underlying value of the AnyVal, which conforms to the Val protocol.
+    let val: any Val
+
+    init(_ val: any Val) {
+        self.val = val
+    }
+
+    func toZinc() -> String {
+        return val.toZinc()
+    }
+}
+
+// AnyVal + Equatable
+extension AnyVal {
+    static func == (lhs: AnyVal, rhs: AnyVal) -> Bool {
+        return lhs.val.equals(rhs.val)
+    }
+}
+
+// AnyVal + Codable
+extension AnyVal {
+    /// Read from decodable data
+    /// See [JSON format](https://project-haystack.org/doc/docHaystack/Json#list)
+    init(from decoder: Decoder) throws {
+        typeLoop: for type in ValType.allCases {
+            if let val = try? type.type.init(from: decoder) {
+                self = .init(val)
+                return
+            }
+        }
+        throw DecodingError.typeMismatch(
+            AnyVal.self,
+            .init(
+                codingPath: decoder.codingPath,
+                debugDescription: "No Val type matched"
+            )
+        )
+    }
+
+    /// Write to encodable data
+    /// See [JSON format](https://project-haystack.org/doc/docHaystack/Json#list)
+    func encode(to encoder: Encoder) throws {
+        try val.encode(to: encoder)
+    }
+}
+
+// AnyVal + Hashable
+extension AnyVal {
+    func hash(into hasher: inout Hasher) {
+        hasher.combine(val)
+    }
+}