From p.dalgaard at biostat.ku.dk  Thu Aug 12 16:05:47 2004
From: p.dalgaard at biostat.ku.dk (Peter Dalgaard)
Date: Thu Aug 12 16:10:02 2004
Subject: [Rd] Disallowing a < b < c in R 2.0.0
Message-ID: <x2acx0h2o4.fsf@biostat.ku.dk>


We're making a change to R's syntax for the 2.0 series. The change
is to disallow associative usage of relational operators (since, e.g.,
a < b < c does not mean what some users think it does.) There are
legitimate uses, but they are quite rare. Further, they might be
considered questionable programming style and issues are always
fixable by inserting parentheses. Use braces in plotmath, e.g.
text(0,0,quote({a<b}<c)).

A not-quite exhaustive check found only 4 CRAN packages containing
this kind of construct and none in Bioconductor. To find problems in
your own code, probably the easiest thing is to run it with a snapshot
version of R, when it hits the CRAN mirrors in a few days.

        -p


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907


[Rd] Disallowing a < b < c in R 2.0.0
Peter Dalgaard