 command-line options that may precede the actual arguments.
This class is useful to process command-line arguments passed to a Lua script.</p>

<p>Each object is created as a table that maps the name of each valid command-line option to its default value.
The type of the default value also defines which values are valid for each command-line option.
For example, a command-line option with a numeric default value will only accepts values that denote numbers.
These objects behave like functions that take as 