Arguments and values to get.

[Gregor.pa@Xerox.ARPA]

This (admittedly minor) question came up while we were writing up some
of the CommonLoops metaclass protocols.

Why does Common-Lisp GET take a default-value argument instead of
returning a second value indicating whether the property actually
exists?

Originally we had wanted to make CommonLoops' internal slot-access
function return a second value saying whether or not the slot-existed
but we ended up changing it to be more like GET.