Parses options which have a parameter and which may appear only once. option-value on <parameter-option-parser> returns either #f or a <string>. If the option appears more than once on the command line, the rightmost value is used.
-cred, -c red, -c=red, -c = red, --color red, --color=red, --color = red
concrete free sealed
| long-options: | An instance of <list>. Specifies the long options handled by this parser, represented as strings. Defaults to #(). |
| short-options: | An instance of <list>. Specifies the short options handled by this parser, represented as strings. Defaults to #(). |
| description: | An instance of <string>. A description of the options handled by this parser. Defaults to “”. |