CHANGES IN VERSION R VERSION 0.60

R is about to become an official part of the GNU project.
To quote RMS (Richard Stallman)

		``I hereby dub R GNU software!''


NEW FEATURES

    o	There has been a major change in directory structure
	masterminded by Kurt Hornik.
	library(.) now attaches ``package''s which are better
	integrated, see "?library".  Packages may be available from outside
	the RHOME path via the .lib.loc variable.

    o	The documentation format (of files in src/library/<package>/man/ )
	has changed to a more easily parsable LaTeX like format.
	The doc files now all end in `.Rd'.
	etc/Rman2Rd  can be used to translate old-style documentation to
	the new one.
	The translation to *roff, LaTeX and HTML is now done using
	etc/Rdconv, written in Perl by Fritz Leisch.

	The HTML online help produced has now links which work.
	The manual (in doc/manual/) now includes a section on the
	documentation format and on mathematical text in graphs.

	etc/ further contains `Sd2Rd' for (partial) translation of S `.d'
	documentation to Rd, and
	`Rd2txt' and `Rd2dvi' for easy previewing of single Rd files.

    o	The use of "names" on one dimensional arrays will now produce
	sensible results.  This means that for most purposes,
	one dimensional arrays can be treated like vectors.

    o	We have a applied a patch from mward@wolf.hip.berkeley.edu
	which should substantially improve the speed of (vector)
	arithmetic.

    o	The modeling formula handler has been expanded so that it
	accepts y ~ 0 + x as a "through the origin" specification.
	models with no parameters are now acceptable.

    o	"cov", "cor" and "var" now produce a matrix result if either
	of their x or y arguments is a matrix.	Dimnames are propagated
	in a sensible fashion.

    o   New chisq.test(.) and prop.test() from Kurt Hornik.

    o   New read.fwf(.) for reading fixed width format (KH).

    o   New str(.) [alternative to summary(.) for programmers] (MM).

    o   New example data sets "esoph", "infert" and "anscombe" (TL),
	"iris3" (KH) and "stackloss" (MM).

    o   source(.) has several new arguments, notably ``echo = FALSE''.
	This is applied in the new function  demo(.) which runs all the
	code in demos/ (but dynload).

    o   strheight(.) is new, accompanying strwidth(.).
	Both now work for mathematical expressions (Paul Murrell).

    o   The LaTeX version of the manual (-> doc/manual/) now has an index.

    o   EVERY *.Rd file in src/library/base/man/ has now at least one \keyword

    o	New package (`library(.)') "stepfun" for step functions, incl.
	empirical distributions.


BUG FIXES

    o   Regular expression matching is now done with system versions
	of the regexp library.  This should fix compilation problems
	on some platforms.

    o	"approx" and "approxfun", have had some minor adjustments.
	which fix the interpretation of the rule= argument.  The
	code for piecewise constant case is now internal C code
	that than interpreted.	This should boost performance in
	this case.

    o	There has been a minor fixup of "model.frame" to ensure that
	subsets, weights, etc are handled properly.

    o	Model fitting of the form

		 lm(y~., data=df)
		glm(y~., data=df)

	will now work.	The RHS of the model will consist of an
	additive model containing all (non-respose) variabels in the
	given data frame.

    o	The following type of assignment to data frame subsets

		z <- data.frame(x=rnorm(10),y=rnorm(10),z=rnorm(10))
		z[,1:2] <- matrix(1:20,nc=2)

	was producing incorrect results.  The solution was to wrap
	an implicit "as.data.frame" around the RHS.

    o	"[.data.frame" no longer has a default drop=TRUE argument.
	This means that subsetting a data frame with "[" will always
	yield a data frame.

    o	There was a swap of coordinates internally in "mtext" which
	meant that labels were coming out in the wrong place.  Fixed.

    o	Syntax errors in parse(text="...") would cause R to terminate
	with a segmentation violation.	This no longer happens, although
	the result is still not perfect (the parse() returns).
	This will be fixed by a future parse rewrite.

    o   rainbow, topo.colors, etc., now also work with n in {1,2};
	don't return duplicate neighbor colors anymore.

    o   legend has new `text.width' argument and now also works with
	mathematical expressions as text.

    o   hist() now works better, has a `plot = TRUE' argument, and returns
	something useful.

    o   barplot() improved for `names', now returns vector of midpoints.

    o   lm(), lm.fit, lm.wfit (was `lm.w.fit'):  Made more compatible.
	Dealing with (close to) collinear situations is still not flexible
	enough.

    o   internal postcript() improved (missing lines in boxplot(.)).

    o   Improvement to many (even most ?) documentation (.Rd) files.

    o   Numerous other fixes of minor things ...



		  CHANGES IN VERSION R VERSION 0.50

WARNING!!!

 o  A change in the way that "expressions" are implemented means that
    saved data images which contain expressions will probably not
    restore properly.

NEW FEATURES

 o  The installation of documentation has now been streamlined.
    Many manual entries have been revised.

 o  "expressions" are now implemented as a basic type rather than as
    a class of object.  This change was made as move toward compatibility
    with S and also to implement mathematical annotation in graphs.
    For some examples of the latter, see ?text and ?title.

 o  "eigen" can now handle complex and non-symmetric matrices.

 o  Libraries are now attached by loading their code into newly created
    environment frames on the search path rather than in with the general
    system code.  This means that libraries can be unloaded as well as
    loaded.  They can also have .First.lib and .Last.lib functions.
    The variable .Libraries has been replaced by .library() but should not
    be needed much anymore.

 o  There is now an experimental function called "delay" which creates
    a promise to evaluate an expression.  This provides direct access
    to the lazy evaluation mechanism used by R.

 o  >>>>  'make tests'   allows to test--run all the help() examples.

 o  New functions   matplot / matpoints / matlines.

 o  cut has 2 new arguments. 'right = TRUE' gives intervals closed on the
	right, open to the left (as S); 'right = FALSE' allows to reverse
	this. The code for default label construction has been enhanced,
	and can be controlled by the new argument 'dig.lab'.

 o  legend(.) has 2 new arguments 'cex' (obvious) and 'merge = FALSE'.
	-> ?legend.
 o  deparse  has a 2nd argument allowing for a kind of line width.
 o  There is now print.density (method).

 o  many help(.) pages have been updated with working examples,
	and several new ones have been created.

 o  influence.measures() and lm.influence now allow to get at the usual
    regression diagnostics.

BUG FIXES

 o  The "is.object" function has been with drawn.

 o  A bug which prevented the "pictex" graphics driver from working
    has been fixed.

 o  Regression diagnostics obtained with "lm.influence" now work when
    there are weights.	This means they should work for glms.

 o  There was a problem in parsing files from statements which were
    separated from following statements by ";" (e.g. data(iris); iris).
    This is fixed.

 o  Comments are handled better in functions.  The rule is that they
    are shifted to just before their statements.  Comments after the
    last statement of a function are lost.

 o  It is now possible to perform complicated mutations of expressions.
    For example
	e <- quote(f(x=1,y=2))
	names(e)[[2]] <- "a"
    will change the x= argument tag into a=.  In the past this produced
    odd error messages.

 o  The length function now tries to return a "sensible" value for all
    the built-in types.	 For example, symbols now have length 1.

 o  "update" should now work in both "lm" and "glm" models.

 o  The functions Re, Im, Mod, Arg and Conj will now accept real-valued
    arguments and return the obvious results.

 o  Minor graphics cleanup.

 o  A fix for convergence problems in glm from Thomas Lumley included.

 o  A new version of qt() should not take infinitely long to get an
    answer in the large degrees if freedom case.  The underlying code
    (Hill 1970, CACM) appears to be much faster and more accurate than
    Splus.

 o  A final Newton step has beed added to give a final "polish" to
    the quantiles produced by pnorm().	These should be close to full
    accuracy now.

 o  A bug in qbeta found by Martin Maechler has been fixed.  This should
    speed up quantile computation for the F and Beta distributions.
    Further improvements in qbeta(.) by MM.  No infinite loops anymore.

 o  rainbow(.) now allows "start > end" indexing the "color circle".
    topo.colors(n), terrain.colors(n), heat.colors(n) now also work for n=1,2.

 o  ?"+" now works.

 o  tapply has been fixed as indicated by T. Lumley.