Version numbers have the format <major>.<minor>.<subminor>, like 0.9.2.
This function compares the current version number of ggplot2 against the
version, which is the most recent version before the
function (or other object) was deprecated.
The last version of ggplot2 where this function was good (in other words, the last version where it was not deprecated).
The message to print.
gg_dep will give an error, warning, or message, depending on the
difference between the current ggplot2 version and the specified
If the current major number is greater than
version's major number,
or if the current minor number is more than 1 greater than
minor number, give an error.
If the current minor number differs from
version's minor number by
one, give a warning.
If the current subminor number differs from
number, print a message.