No, string being an openarray does not seem to be mentioned in the manual.
That example might not work perhaps because of the excessive generic arguments?
Try this:
proc encrypter*(data: array or seq or string, key: string): typeof(data) =
...
Run
This uses something called [implicit
generics](https://nim-lang.org/docs/manual.html#generics-implicit-generics) and
is analogous to
proc encrypter*[T: array or seq or string](data: T, key: string):
typeof(data) = ...
Run
You can simplify the signature further with
proc encrypter*[T: array or seq or string](data: T, key: string): T = ...
Run
