R-alpha: NEW VERSION 0.16

Ross Ihaka (ihaka@stat.auckland.ac.nz)
Fri, 7 Feb 1997 15:20:17 +1300 (NZDT)

From: Ross Ihaka <ihaka@stat.auckland.ac.nz>
Date: Fri, 7 Feb 1997 15:20:17 +1300 (NZDT)
Message-Id: <199702070220.PAA01993@stat13.stat.auckland.ac.nz>
To: r-testers@stat.math.ethz.ch
Subject: R-alpha: NEW VERSION 0.16

VERSION 0.16 of R is now available as


The major change in this version is a major rework of the "object system".

"UseMethod" and "NextMethod" now agree with the descriptions given in the
``Statistical Models in S'' book.  We are still missing a ``Group Method''
mechanism, but this should appear in the near future.

In addition there have been some changes to "attach", "detach" and the
associated functions "ls" and "objects".  There is now a function called
"search" which returns the search path in use to find values associated
with names.  The function "attach", "detach" and "ls" all take a "pos="
argument as refering to a position on the search list.

Future changes should bring the R runtime environment more into line
with S - libraries and external databases will be "attached" and "detached"
and generally look rather more S like.  "assign" and "get" will be given
a "pos=" argument.

More extensive change notes appear below.



 *  The implementation of UseMethod and NextMethod has been redone so that
    the behavior of R matches the docmentation given with S (but beware
    that the behavior of S does not match that documentation.  This should
    make it possible in the near future to add "group methods", which will
    complete the "object" system.

 *  The functions "attach", "detach", "ls" and "objects" have been reworked
    so that they all share a common "pos=" argument.  There is also a new
    "search" function which shows the current object search path.  Note that
    R does not maintain data structures in external directories so that the
    R implementation is only an approximation to that of S.  However S users
    should feel at home using these functions.  To obtain the names of the
    built in functions use one of:


    The function "builtins" is now deprecated and will eventually go away.

 *  A ".Device" variable is set when a graphics device driver is started.

 *  Color specification has been improved.  Color specifications can now be
    one of 1) a name (from the X11 rgb database), 2) an index into a fixed
    table of 8 colors (for compatibility with S) or 3) a specification of
    the form "#RRGGBB" where RR, GG, and BB are numbers consisting of pairs
    of hexadecimal digits which give the levels of the red, green and blue
    primaries in the color.  Functions like "rgb" and "hsv" now produce this
    final form.  Mixed specifications like

	c(1, 2, "lightcyan", "#0000FF")

    will work.

 *  Functions "sweep" and "crossprod" have been added.


 *  Use of the graphics parameter "omd" now works correctly.

 *  A fix to "glm" so that non full-rank design matrices are handled
    (more) correctly.

 *  Some memory management problems which allowed some functions to alter
    their arguments has been fixed (this is an on-going battle).

 *  Data frame subset manipulation is now much more robust.  When
    manipulation of a data frame produces a "ragged" structure the
    data.frame-ness is lost.

 *  Changes to subsetting of data frames so that expressions like

	x$new <- runif(nrow(x))
	x[3] <- as.character(x[3])

    can be used to introduce new variables into a data frame or to change
    the mode of existsing variables.

 *  Fixes to "data.frame" and "read.table" to make them more flexible.

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