Class description
An option that can be specified on the command-line. It has the following slots:
nameThe name of the argument (prefixed by dashes "-" if optional).
typeThe class type of the argument.
helpSome help text to display.
variableAn optional variable used to set a parsed value.
defaultA default value if not present on the command-line.
convertA converter from a string argument.
validateA validater to constrain the specified argument.
constA constant value to be used if the argument is specified.
required?A flag to indicate this option is required.
metaA meta variable name used to display.
#argsThe number of arguments to parse specified as an integer, "*" (zero or more), "+" (one or more), or "?" (optionally one) argument.


TUPLE: option
name type help variable default convert validate const
required? meta #args ;