mkoptions is a function that returns a function that
behaves like options, with an attached
internal/local list of key-value pairs.
Usage
mkoptions(...)
.options(..., .DATA)
Value
mkoptions returns a function.
Arguments
...
list of keys or key-value pairs.
For mkoptions these define inital/default key-value pairs.
.DATA
a list or an environment with an element .options.
Functions
.options(): is a low-level function that mimics the behaviour
of the base function options, given a set
of key-value pairs.
It is the workhorse function used in mkoptions and package-specific
option sets (see setupPackageOptions)