Most keyboard and mouse mappings are inserted into a keymap by calling the keymap's map-function method. However, ``meta'' combinations require special attention. The ``m:'' prefix recognized by map-function applies only to the Meta key that exists on some keyboards. By convention, however, ``meta'' combinations can also be accessed by using ``ESC'' or ``c:['' as a prefix. Further, it may be useful to use a different modifier key for ``meta'' on platforms without a Meta key.
This procedure binds all of the key-bindings obtained by prefixing key with a meta-prefix to func in keymap.