Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!uunet!mcsun!hp4nl!charon!jurjen From: jurjen@cwi.nl (Jurjen NE Bos) Newsgroups: comp.sys.handhelds Subject: Re: HP 48: Weird IFERR | THEN END behavior Message-ID: <2648@charon.cwi.nl> Date: 5 Dec 90 13:42:18 GMT References: Sender: news@cwi.nl Lines: 15 This has nothing to do with IFERR, but it has to do with LASTARG. I don't have the manual handy, but it is true that any action that results in the evaluation of an algebraic or user program results in influencing the LASTARG register according to the behaviour of that program. So the EVAL function, and all operations that do evaluation, change the LASTARG during the computation of programs and algebraics, influencing the LASTARG register in cometimes unexpected ways. Operations doing evaluation are not only EVAL and |, but also differentiation, integration, ISOL, QUAD, STR-> (OBJ-> for strings), and many more. The LASTARG register contains what is left on the stack after an error, so you have to take care if you use IFERR. Hope to have cleared this up.