optparse
is primarily intended to be used with Rscript. It facilitates writing #! shebang scripts
that accept short and long flags/options. It can also be used from Rdirectly, but is probably less
useful in this context.See package vignette for a more detailed example.
Notes on naming convention in package:
1. An option is one of the shell-split input strings.
2. A flag is a type of option. a flag can be defined as having no argument (defined below), a required
argument, or an optional argument.
3. An argument is a type of option, and is the value associated with a flag.
4. A long flag is a type of flag, and begins with the string --. If the long flag has an associated
argument, it may be delimited from the long flag by either a trailing =, or may be the subsequent
option.
5. A short flag is a type of flag, and begins with the string -. If a short flag has an associated
argument, it is the subsequent option. short flags may be bundled together, sharing a single leading
"-", but only the final short flag is able to have a corresponding argument.