that simply loading it has no visible effect---that should not enable
the feature.@footnote{Consider that the package may be loaded
arbitrarily by Custom for instance.} Users will request the feature by
-invoking the command.
+invoking the command, which will often be constructed as a minor mode.
+
+@cindex unloading packages
+If your package contains functions which do modify oridinary Emacs
+behavior, for instance by adding functions to hooks, define a function
+@code{@var{feature}-unload-hook} where @var{feature} is the name of
+the feature the package provides. This function should undo any such
+changes, e.g.@: by turning off a minor mode, when
+@findex unload-feature
+@code{unload-feature} is used.
@item
It is a bad idea to define aliases for the Emacs primitives. Use the
of Unix systems.
@item
+@findex next-line
+@findex previous-line
+@findex forward-line
Don't use @code{next-line} or @code{previous-line} in programs; nearly
always, @code{forward-line} is more convenient as well as more
predictable and robust. @xref{Text Lines}.