nested arithmetic expansion

[Atom Smasher <atom@xxxxxxxxxxx>]

how come $[...] doesn't work when nested in a parameter, but the other 
(older?) form $((...)) does?

	% print ${$((2+3))}
	5

	% print ${$[2+3]}
	<nothing>


--
        ...atom

 ________________________
 http://atom.smasher.org/
 762A 3B98 A3C3 96C9 C6B7 582A B88D 52E4 D9F5 7808
 -------------------------------------------------

	"So what do we do if we get bitten by something deadly, then?"
	 He blinked at me as if I was stupid.
	 "Well what do you think you do?" he said. "You die of course.
	 That's what deadly means."
		-- Douglas Adams, Last Chance To See