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<== Date ==> <== Thread ==>

Subject: Re: Long expressions using MAX and MIN in CALC fields
From: Tim Mooney <mooney@aps.anl.gov>
To: Andrew Johnson <anj@aps.anl.gov>
Cc: "Redman, Russell O." <Russell.Redman@nrc-cnrc.gc.ca>, "Tech-Talk (E-mail)" <tech-talk@aps.anl.gov>
Date: Thu, 27 Feb 2003 13:51:26 -0600
Andrew, re...,

> The GNU C++ compiler has a built-in extension for MIN and MAX that uses <?
> and >? respectively as the binary operators.  Although I'd prefer that we
> stick as close as possiblt to the standard C operators and function
> syntax, if a variable-length MIN() and MAX() can't easily be developed
> it's probably better to regard g++ as a sort of standard and re-use their
> operators.

I think <? would be valuable even if min(a,b,c,d,...) existed, because in some
cases using the operator would yield a clearer expression.  But I certainly
agree that sticking to standards is the way to go.  Otherwise we might get more
functions like "loge" (should be "ln"), and operators like "#" (should be "!="
or "<>").
 
To this end, do you happen to know the precedence and associativity of these
operators?  I.e.,
does  a + b <? c   mean  (a + b) <? c   or  a + (b <? c)
does  a <? b <? c  mean  (a <? b) <? c  or  a <? (b <? c)
does  a * b <? c   mean  (a * b) <? c   or  a * (b <? c)
etc.  I haven't been able to find this information online.

-- 
Tim Mooney (mooney@aps.anl.gov; 630-252-5417)
Advanced Photon Source
APS Operations Division
Beamline Controls & Data Acquisition Group

References:
Long expressions using MAX and MIN in CALC fields Redman, Russell O.
Re: Long expressions using MAX and MIN in CALC fields Andrew Johnson

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