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From: f31915s@taltta.hut.fi (Juha Haataja)
Newsgroups: comp.lang.apl
Subject: Re: composition of APL expressions
Summary: Quad-R in APL2
Message-ID: <25117@santra.UUCP>
Date: 11 Sep 89 06:22:42 GMT
References: <215026@<1989Aug26> <49700012@uicsrd.csrd.uiuc.edu>
Sender: news@santra.UUCP
Reply-To: lk-joh@finhut.bitnet (Juha Haataja)
Organization: Helsinki University of Technology, Finland
Lines: 23

In article <49700012@uicsrd.csrd.uiuc.edu> jaxon@uicsrd.csrd.uiuc.edu writes:
>I always forget to say "R<-" before "BIG_EXPENSIVE_FUNCTION_CALL".  I guess
>just preserving the last computed result would be enough for me.  APL2 has
>something called Quad-R that might do this already... any IBMers know?
>
>regards  greg jaxon  (jaxon@uicsrd.uiuc.edu)


Quad-R (and Quad-L) in APL2 contains right (and left) argument of the 
current function in case of interrupt or error. This is very convenient
when debugging programs: it is possible to list the arguments and also
to respecify them and try to resume execution. So, the answer to your
question is no - Quad-R (and Quad-L) is set only when an error or
interrupt occurs in a primitive function, so it can't be used to
query the last computed result.

But it sure would be nice to be able to recall that last result!


__________________________________________________________________________
| Juha Haataja                                  | lk-joh@finhut.bitnet   |
| Helsinki Univ. of Technology Computing Centre | jhaataja@sorvi.hut.fi  |
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