Defines a function that allow to get/assign a global
variable whose value is ensured to be reset after each
access.
Usage
oneoffVariable(default = NULL)
Arguments
default
default value to which the global variable
is reset after each access. Default is NULL.
Value
a function with one argument (value) that provides
get/set access to a global variable. If called with a
value, it assigns this value to the global variable. If
called with no argument, it returns the current value of
the global variable and reset it to its default value --
as defined at its creation.