Allow failure() to be called with string argument

questionable/results.nim

@@ -6,6 +6,8 @@ include ./errorban
 
 export resultsbase
 
+type ResultFailure* = object of CatchableError
+
 template `?!`*(T: typed): type Result[T, ref CatchableError] =
   Result[T, ref CatchableError]
 
@@ -15,6 +17,9 @@ proc success*[T](value: T): ?!T =
 proc failure*(T: type, error: ref CatchableError): ?!T =
   err(?!T, error)
 
+proc failure*(T: type, message: string): ?!T =
+  T.failure newException(ResultFailure, message)
+
 template `->?`*[T,U](value: ?!T, expression: U): ?!U =
   if value.isErr:
     U.failure(value.error)

testmodules/result/test.nim

@@ -82,6 +82,11 @@ suite "result":
     check parseInt("42").catch == 42.success
     check parseInt("foo").catch.error of ValueError
 
+  test "failure can be called with string argument":
+    let value = int.failure("some failure")
+    check value.error of ResultFailure
+    check value.error.msg == "some failure"
+
   test "unary operator `-` works for results":
     check -(-42.success) == 42.success
     check -(int.failure(error)) == int.failure(error)