| opt_arguments/3 | Extract commandline options according to a specification. |
| opt_help/2 | True when Help is a help string synthesized from OptsSpec. |
| opt_parse/4 | Equivalent
to opt_parse(OptsSpec, ApplArgs, Opts, PositionalArgs, []). |
| opt_parse/5 | Parse the arguments Args (as list of atoms) according to OptsSpec. |
| parse_type/3 | Hook to parse option text Codes to an object of type Type. |