R-alpha: compatibility

Ross Ihaka (ihaka@stat.auckland.ac.nz)
Thu, 30 May 1996 14:55:50 +1200


Date: Thu, 30 May 1996 14:55:50 +1200
From: Ross Ihaka <ihaka@stat.auckland.ac.nz>
Message-Id: <199605300255.OAA05346@stat.auckland.ac.nz>
To: r-testers@stat.math.ethz.ch
Subject: R-alpha: compatibility
In-Reply-To: <9605290833.AA13280@alpha.luc.ac.be>

Jim Lindsey writes:
 > Re compatibility of R with S-plus:
 >   First, I have never used S-plus and know it only through V&R. However
 > there is S code I would like to use.
 >   From what I have heard of S, trying to keep up with changes between
 > versions would be a disaster. Also we should not worry about porting code in
 > the other direction, from R to S.
 >   I think that R should be compatible on input to functions and what they
 > return, but not necessarily what is printed out or plotted (such as the
 > t-tests for coefficients in glms which are often misleading). Functions
 > should have all the S options, plus any extra useful ones. Defaults need not
 > be the same (helmert contrast...). Take hist().
 >   It now imitates the ugly (in my opinion) S axes (because they can
 > start or stop a third of the way along) instead of boxing as it used
 > to. On the other hand, it has freq=T instead of prob=F and is missing
 > plot=T in the options. It does not return a list with the counts and
 > breaks.  (This comparison comes from reading V&R.) Thus compatibility
 > is on the wrong end.
 
We are only two part-timers, and our priority is to get the language
infra-structure right.  We also face competing demands -- the freq=
option is there to support a local colleague who wants it that way
in his introductory course.

hist is a particular disaster area - the weird idea that you should
choose cell boundaries at "nice" values means it is very hard to
predict how many cells will actually show up.

Of course, it someone wanted to write the definitive "hist" we would
gladly incorporate it :-).
	Ross
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