Alphanumeric validates whether a string is an alphanumeric string.

AlphanumericExt validates whether a string is an alphanumeric string, but a small set of extra characters allowed.

Integer validates whether a string is an integer string.

UnixPath validates whether a string is an unix path string.

URL validates whether a string is an URL string.

Argument contains the name of the validation type and the validation function.

String is the validation function used for checking whether a string is valid or not.