`getopt'
--------

getopt([KEY])
     :: Returns the value of an option.

RETURN
     object

   * When a user defined function is called, the number of arguments
     must be equal to that in the declaration of the function.  A
     function with indefinite number of arguments can be realized by
     using OPTIONS (*note option::).  The value of a specified option
     is retrieved by `getopt'.

   * If `getopt()' is called with no argument, then it returns a list
     `[[key1,value1],' `[key2,value2],...]'.  In the list, each `key'
     is an option which was specified when the function executing
     `getopt' was invoked, and `value' is the value of the option.

   * If an option KEY is specified upon a function call, `getopt'
     return the value of the option. If such an option is not specified,
     the it returns an object of VOID type whose object identifier is
     -1. By examining the type of the returned value with `type()', one
     knows whether the option is set or not.

   * Options are specified as follows:

          xxx(A,B,C,D|x=X,y=Y,z=Z)

     That is, the options are specified by a sequence of KEY=VALUE
     seperated by `,', after `|'.

References
     *Note `option': option, *Note `type': type.

