Conditionally Support CustomStringConvertible on Result

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Sources/P4/Support.swift

@@ -32,8 +32,8 @@ public struct Nothing: CustomStringConvertible {
 }
 
 
-public enum Result<T>: Equatable, CustomStringConvertible {
-    case Ok(T)
+public enum Result<OKT>: Equatable {
+    case Ok(OKT)
     case Error(Error)
 
     public static func == (lhs: Result, rhs: Result) -> Bool {
@@ -53,7 +53,9 @@ public enum Result<T>: Equatable, CustomStringConvertible {
         }
         return nil
     }
+}
 
+extension Result where OKT: CustomStringConvertible {
     public var description: String {
         switch self {
             case Result.Error(let e):
@@ -64,6 +66,17 @@ public enum Result<T>: Equatable, CustomStringConvertible {
     }
 }
 
+extension Result {
+    public var description: String {
+        switch self {
+            case Result.Error(let e):
+                return e.msg
+            case Result.Ok(_):
+                return "Ok"
+        }
+    }
+}
+
 @freestanding(expression) public macro RequireOkResult<T>(_: Result<T>) -> Bool =
     #externalMacro(module: "Macros", type: "RequireResult")
 @freestanding(expression) public macro RequireErrorResult<T>(_: Error, _: Result<T>) -> Bool =

Tests/p4lmTests/SupportTests.swift

@@ -0,0 +1,44 @@
+// p4rse, Copyright 2026, Will Hawkins
+//
+// This file is part of p4rse.
+
+// This file is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import Foundation
+import P4
+import Macros
+import SwiftTreeSitter
+import Testing
+import TreeSitter
+import TreeSitterP4
+
+@testable import Parser
+
+struct NotStringConvertible {}
+
+struct StringConvertible: CustomStringConvertible {
+    public var description: String {
+        return "CONVERTED"
+    }
+}
+
+@Test func test_result_type_description_not_convertible() async throws {
+    let result: Result<NotStringConvertible> = Result.Ok(NotStringConvertible());
+    #expect(result.description == "Ok")
+}
+
+@Test func test_result_type_description_convertible() async throws {
+    let result: Result<StringConvertible> = Result.Ok(StringConvertible());
+    #expect(result.description == "CONVERTED")
+}