Extend the class attribute by a given class name
Arguments
- x
R object
- className
name of the class to be added to x
- first
if TRUE
(default) the className
is prepended to
the vector of existing class names, otherwise appended to the end of the
vector
- dbg
if TRUE
(default), debug messages are shown.
Value
x
with the class
attributed extended by
className
(only if x
did not yet inherit from
className
)