Provide conversion to string `$` for Results

questionable/results.nim

@@ -73,6 +73,12 @@ proc isFailure*[T](value: ?!T): bool =
 
   value.isErr
 
+proc `$`*[T](value: ?!T): string =
+  if value.isSuccess:
+    "success(" & $(!value) & ")"
+  else:
+    "failure(\"" & $(value.error.msg) & "\")"
+
 template `->?`*[T,U](value: ?!T, expression: ?!U): ?!U =
   if value.isFailure:
     U.failure(value.error)

testmodules/results/test.nim

@@ -14,6 +14,10 @@ suite "result":
     check (?!string is Result[string, ref CatchableError])
     check (?!seq[bool] is Result[seq[bool], ref CatchableError])
 
+  test "conversion to string $ works for ?!Types":
+    check $42.success == "success(42)"
+    check $(int.failure "some error") == "failure(\"some error\")"
+
   test "! gets value or raises Defect":
     check !42.success == 42
     expect Defect: discard !int.failure error