[det]argv_usage(:Level)debug. Other meaningful
options are informational or warning. The help
page consists of four sections, two of which are optional:
- The header is created from
opt_help(help(header), String). It is optional. - The usage is added by default. The part behind
Usage: <command>is by default[options]and can be overruled usingopt_help(help(usage), String). - The actual option descriptions. The options are presented in the order they are defined in opt_type/3. Subsequent options for the same destination (option name) are joined with the first.
- The footer_ is created from
opt_help(help(footer), String). It is optional.
The help provided by help(header), help(usage)
and help(footer) are either a simple string or a list of
elements as defined by
print_message_lines/3.
In the latter case, the construct \Callable can be used to
call a DCG rule in the module from which the user calls argv_options/3.
For example, we can add a bold title using
opt_help(help(header), [ansi(bold, '~w', ['My title'])]).