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The macro define-alternatives
can be used to define
generic commands. These are interactive functions whose
implementation can be selected from several alternatives, as a matter
of user preference.
Define the new command command, a symbol.
When a user runs M-x command RET for the first time, Emacs prompts for which real form of the command to use, and records the selection by way of a custom variable. Using a prefix argument repeats this process of choosing an alternative.
The variable command-alternatives
should contain an alist
with alternative implementations of command.
Until this variable is set, define-alternatives
has no effect.
If customizations is non-nil
, it should consist of
alternating defcustom
keywords (typically :group
and
:version
) and values to add to the declaration of
command-alternatives
.