CurrentDirectoryOnEmpty replaces pointer value with current directory if the value is an empty string.

DefaultOnEmpty replaces pointer value with default value if the value is an empty string.

FailOnEmpty returns an error if the pointer value is an empty string.

GeneratePasswordOnEmpty replaces pointer value with a newly generated password if the value is an empty string.

ReadPassword reads password into ptr from stdin - input silenced.

ReadPasswordSubtle reads password from stdin, but prompt goes to stderr rather than stdout.

ReadString reads string into ptr from stdin.

RetryOnEmpty returns a retryError if the value in the ptr is an empty string.