(SI:VS i)	Returns the i-th entity in VS.
(SI:IHS-VS i)	Returns the VS index of the i-th entity in IHS.
(SI:IHS-FUN i)	Returns the function of the i-th entity in IHS.
(SI:FRS-VS i)	Returns the VS index of the i-th entity in FRS.
(SI:FRS-BDS i)	Returns the BDS index of the i-th entity in FRS.
(SI:FRS-IHS i)	Returns the IHS index of the i-th entity in FRS.
(SI:BDS-VAR i)	Returns the symbol of the i-th entity in BDS.
(SI:BDS-VAL i)	Returns the value of the i-th entity in BDS.

(SI:SUPER-GO i tag)
	Jumps to the specified tag established by the TAGBODY frame at
	FRS[i].  Both arguments are evaluated.  If FRS[i] happens to be
	a non-TAGBODY frame, then (THROW (SI:IHS-TAG i) (VALUES)) is
	performed.