- (%funcallable-instance-lexenv fin))
-
-;;; The heart of the magic of funcallable instances ("FINs"). The
-;;; function for a FIN must be a magical INSTANCE-LAMBDA form. When
-;;; called (as with any other function), we grab the code pointer, and
-;;; call it, leaving the original function object in LEXENV (in case
-;;; it was a closure). If it is actually a FIN, then we need to do an
-;;; extra indirection with funcallable-instance-lexenv to get at any
-;;; closure environment. This extra indirection is set up when
-;;; accessing the closure environment of an INSTANCE-LAMBDA. Note that
-;;; the original FIN pointer is lost, so if the called function wants
-;;; to get at the original object to do some slot accesses, it must
-;;; close over the FIN object.
-;;;
-;;; If we set the FIN function to be a FIN, we directly copy across
-;;; both the code pointer and the lexenv, since that code pointer (for
-;;; an instance-lambda) is expecting that lexenv to be accessed. This
-;;; effectively pre-flattens what would otherwise be a chain of
-;;; indirections. (That used to happen when PCL dispatch functions
-;;; were byte-compiled; now that the byte compiler is gone, I can't
-;;; think of another example offhand. -- WHN 2001-10-06)
-;;;
-;;; The only loss is that if someone accesses the
-;;; FUNCALLABLE-INSTANCE-FUN, then won't get a FIN back. This probably
-;;; doesn't matter, since PCL only sets the FIN function.