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What's new in this version:

SIGNIFICANT USER-VISIBLE CHANGES:
Serialization format version 3 becomes the default for serialization and saving of the workspace (save(), serialize(), saveRDS(), compiler::cmpfile()). Serialized data in format 3 cannot be read by versions of R prior to version 3.5.0. Serialization format version 2 is still supported and can be selected by version = 2 in the save/serialization functions. The default can be changed back for the whole R session by setting environment variables R_DEFAULT_SAVE_VERSION and R_DEFAULT_SERIALIZE_VERSION to 2. For maximal back-compatibility, files ‘vignette.rds’ and ‘partial.rdb’ generated by R CMD build are in serialization format version 2, and resave by default produces files in - serialization format version 2 (unless the original is already in format version 3).
The default method for generating from a discrete uniform distribution (used in sample(), for instance) has been changed. This addresses the fact, pointed out by Ottoboni and Stark, that the previous method made sample() noticeably non-uniform on large populations. See PR#17494 for a discussion. The previous method can be requested using RNGkind() or RNGversion() if necessary for reproduction of old results. Thanks to Duncan - Murdoch for contributing the patch and Gabe Becker for further assistance.
- The output of RNGkind() has been changed to also return the ‘kind’ used by sample().

NEW FEATURES:
- Sys.setFileTime() has been vectorized so arguments path and time of length greater than one are now supported.
axis() gets new option gap.axis = NA for specifying a multiplication factor for the minimal “gap” (distance) between axis labels drawn. Its - default is 1 for labels parallel to the axis, and 0.25 for perpendicular ones.
- Perpendicular labels no longer overlap, fixing bug PR#17384.
- The default method of plot() gains new arguments xgap.axis = NA and ygap.axis = NA to be passed to the x– and y– axis(.., gap.axis=*) calls.
- removeSource() now works not only for functions but also for some language objects.
- as.call(), rep.int(), rep_len() and nchar() dispatch internally.
- is(object, class2) looks for class2 in the calling namespace after looking in the namespace of class(object).
- extendrange(.., f) with a length-2 f now extends separately to the left and the right.
- lengths() dispatches internally to S4 methods.
download.file() on Windows now uses URLdecode() to determine the file extension, and uses binary transfer (mode = "wb") also for file extension - ‘.rds’.
- The help page for download.file() now contains the same information on all platforms.
Setting C locale for collation via environment variables LC_ALL and LC_COLLATE and via a call to Sys.setlocale() now takes precedence over - environment variable R_ICU_LOCALE.
- There is a new function, nullfile(), to give the file name of the null system device (e.g., ‘/dev/null’) on the current platform.
There are two new options, keep.parse.data and keep.parse.data.pkgs, which control whether parse data are included into sources when keep.source or keep.source.pkgs is TRUE. By default, keep.parse.data.pkgs is now FALSE, which changes previous behavior and significantly reduces space and - time overhead when sources are kept when installing packages.
- In rapply(x, ..), x can also be “list-like” and of length >= 2^{31}.
trimws() gets new optional whitespace argument, allowing more extensive definitions of “space”, such as including Unicode spaces (as wished in - PR#17431).
weighted.mean() no longer coerces the weights to a double/numeric vector, since sum() now handles integer overflow. This makes weighted.mean() - more polymorphic and endomorphic, but be aware that the results are no longer guaranteed to be a vector of type double.
- When loading namespaces, S3 method registrations which overwrite previous registrations are now noted by default (using packageStartupMessage()).
- compiler::cmpfile() gains a version argument, for use when the output file should be saved in serialization format 2.
- The axis labeling in the default method of pairs() may now be toggled by new options horOdd and verOdd.
(Not Windows nor macOS.) Package tcltk now supports an environment variable R_DONT_USE_TK which if set disables Tk initialization. This is - intended for use to circumvent errors in loading the package, e.g. with recent Linux running under an address sanitizer.
The numeric method of all.equal() gets optional arguments countEQ and formatFUN. If countEQ is true, the mean error is more sensible when many - entries are equal.
- outer(x,y, FUN = "*") is more efficient using tcrossprod(u,v) instead of u %*% t(v).
- vcov() is more efficient via new optional arguments in summary.mlm().
- The default method of summary() gets an option to choose the kind of quantile()s to use; wish of PR#17438.
- Fitting multiple linear models via lm() does work with matrix offsets, as suggested in PR#17407.
The new functions mem.maxVSize() and mem.maxMSize() allow the maximal size of the vector heap and the maximal number of nodes allowed in the - current R process to be queried and set.
- news() gains support for ‘NEWS.md’ files.
An effort has been started to have our reference manuals, i.e., all help pages. show platform-independent information (rather than Windows or Unix-alike specifics visible only on that platform). Consequently, the Windows version of X11() / x11() got identical formal arguments to the - Unix one.
- sessionInfo()$running has been factored out in a new variable osVersion.
- slice.index() now also works for multi-dimensional margins.
untar() used with an external tar command assumes this supports decompression including xz and automagically detecting the compression type. This has been true of all mainstream implementations since 2009 (for GNU tar, since version 1.22): older implementations are still supported via the new argument support_old_tars whose default is controlled by environment variable R_SUPPORT_OLD_TARS. (It looks like NetBSD and OpenBSD have - ‘older’ tar commands for this purpose.)
- The new function asplit() allow splitting an array or matrix by its margins.
- New functions errorCondition() and warningCondition() provide a convenient way to create structured error and warning objects.
- .Deprecated() now signals a warning of class "deprecatedWarning", and .Defunct() now signals an error of class "defunctError".
- Many ‘package not found’ errors are now signaled as errors of class "packageNotFoundError".
As an experimental feature, when loadNamespace() fails because the requested package is not available the error is initially signaled with a - retry_loadNamespace restart available. This allows a calling handler to try to install the package and continue.
- S3method() directives in ‘NAMESPACE’ can now also be used to perform delayed S3 method registration.
Experimentally, setting environment variable _R_CHECK_LENGTH_1_LOGIC2_ will lead to warnings (or errors if the variable is set to a ‘true’ - value) when && or || encounter and use arguments of length more than one.
- Added "lines" and "chars" coordinate systems to grconvertX() and grconvertY().
- getOption() is more efficient notably for the rare case when called with two arguments, from several contributors in PR#17394.
- In .col(dim) and .row(dim), dim now may also be an integer-valued "double".
- sQuote() and dQuote() get an explicit q argument with obvious default instead of using getOption("fancyQuotes") implicitly and unconditionally.
- unzip() can list archives with comments and with spaces in file names even using an external unzip command.
- Command line completion has a new setting rc.settings(dots = FALSE) to remove ... from the list of possible function arguments.
library() no longer checks packages with compiled code match R.version$platform. loadNamespace() never has, and increasingly the ‘canonical - name’ does not reflect the important characteristics of compiled code.
The primitive functions drop() and unclass() now avoid duplicating their data for atomic vectors that are large enough, by returning ALTREP wrapper objects with adjusted attributes. R-level assignments to change attributes will also use wrapper objects to avoid duplicating data for larger atomic vectors. R functions like structure() and unname() will therefore not duplicate data in these settings. Generic vectors as - produced by list() are not yet covered by this optimization but may be in due course.
- In formals(), envir becomes an optional argument instead of being hardwired.
Instead of signalling an error for an invalid S4 object x, str(x) now gives a warning and subsequently still shows most parts of x, e.g., when - slots are missing.
gamma(x) and lgamma(x) no longer warn when correctly returning Inf or underflowing to zero. This helps maximum likelihood and similar - computations.
convertColor() is now vectorized, so a lot faster for converting many colours at once. The new argument vectorized to colorConverter() ensures - that non-vectorized colour converters still work. (Thanks to Brodie Gaslam.)
download.file() and url() get new argument headers for custom HTTP headers, e.g., allowing to perform basic http authentication, thanks to a - patch contributed by Gábor Csárdi.
- File-based connection functions file(), gzfile(), bzfile() and xzfile() now signal an error when used on a directory.
- For approx(), splinefun() etc, a new setting ties = c("ordered", ) allows skipping the sorting and still treat ties.
format(x) gives a more user friendly error message in the case where no method is defined. A minimal method is provided in format.default(x) - when isS4(x) is true.
which(x) now also works when x is a long vector, thanks to Suharto Anggono's PR#17201. NB: this may return a double result, breaking the - previous guarantee of an integer result.
seq.default() is more careful to return an integer (as opposed to double) result when its arguments are large and/or classed objects; see - comment #9 of Suharto Anggono's PR#17497.
The plot() method for lm and glm fits, plot.lm(), gains a new option iter.smooth with a default of 0 for binomial fits, no longer down-weighting - when smoothing the residuals.
- zip() passes its list of files via standard input to the external command when too long for the command line (on some platforms).
- data() gains an overwrite argument.
- t.test() now also returns the standard error (in list component stderr).
- model.matrix(*, contrasts.arg = CC) now warns about invalid contrasts.args.
- Performance of substr() and substring() has been improved.
- stopifnot() has been simplified thanks to Suharto Anggono's proposals to become considerably faster for cheap expressions.
The default ‘user agent’ has been changed when accessing http:// and https:// sites using libcurl. (A site was found which caused libcurl to - infinite-loop with the previous default.)
sessionInfo() now also contains RNGkind() and prints it when it differs from the default; based on a proposal and patch by Gabe Becker in - PR#17535. Also, RNGversion(getRversion()) works directly.
library() and require() now allow more control over handling search path conflicts when packages are attached. The policy is controlled by the - new conflicts.policy option.
- barplot() gets a formula method, thanks to a patch proposal by Arni Magnusson in PR#17521.
- pmax() and pmin(x) now also work for long vectors, thanks to Suharto Anggono's PR#17533.
- bxp() now warns when omitting duplicated arguments.
New hcl.colors() function to provide wide range of HCL-based colour palettes with much better perceptual properties than the existing RGB/- HSV-based palettes like rainbow().
- Also a new hcl.pals() function to list available palette names for hcl.colors().
- Contributed by Achim Zeileis.
- The default colours for image() and filled.contour() are now based on hcl.colors().
- The palette-generating functions rainbow(), gray.colors(), etc. get a new rev argument to facilitate reversing the order of colors.
New str2lang() and str2expression() as streamlined versions of parse(text=., keep.source=FALSE) allow to abstract typical call constructions, - e.g., in formula manipulations. (Somewhat experimental)
Add update_PACKAGES() for incrementally updating a package repository index, instead of rebuilding the index from scratch. Thanks to Gabe Becker - in PR#17544 for the patch, based on part of his switchr package.

INSTALLATION on a UNIX-ALIKE:
- The options selected for the C++ compiler default to the C++11 standard if supported, otherwise to the C++98 standard.
- Visibility macros such as C_VISIBILITY can now be user-set (including to empty), e.g. in ‘config.site’.
- Macro FCLIBS, which has sometimes been needed on Solaris, has been renamed to FCLIBS_XTRA.
Macro F77 is always set to the value of FC, so the latter should be set to user-select the Fortran compiler for both fixed-form and free-form - Fortran. In particular, gfortran is now the first choice for F77, not f95.
Macros FFLAGS and FCFLAGS remain distinct to allow for a compiler which needs a flag to select free- or fixed-form Fortran (most use the - source-file extension to choose: ‘.f’ is fixed-form and ‘.f90’ and ‘.f95’ are free-form).
- If only one of them is set, its value is used for both.
The special-casing of CFLAGS, CXXFLAGS and FFLAGS for Intel compilers on Linux has been removed: we do not have recent experience but the - generic defaults now chosen are the same as those previously special-cased for x86_64.
- If necessary, override the defaults on the configure command line or in file ‘config.site’.
- Long-untested configure support for HP-UX and very old versions of Linux has been removed.
configure --with-blas (without specifying a value) includes OpenBLAS in its search (before ATLAS and a generic BLAS). This follows recent - versions of the ax_blas autoconf macro.
- The configure macro MAKEINFO has been updated to TEXI2ANY.
- Support for make install-strip has been enhanced.

PACKAGE INSTALLATION:
Source package installation is by default ‘staged’: the package is installed into a temporary location under the final library directory and - moved into place once the installation is complete. The benefit is that partially-installed packages are hidden from other R sessions.
The overall default is set by environment variable R_INSTALL_STAGED. R CMD INSTALL has new options --staged-install and --no-staged-install, and packages can use the StagedInstall field in their ‘DESCRIPTION’ file to opt out. (That opt-out is a temporary measure which may be withdrawn in - future.)
- Staged installation requires either --pkglock or --lock, one of which is used by default.
The interpretation of source code with extension ‘.f’ is changing. Previously this denoted FORTRAN 77 code, but current compilers no longer have a FORTRAN 77 mode and interpret it as ‘fixed-form’ Fortran 90 (or later where supported) code. Extensions ‘.f90’ and ‘.f95’ continue to indicate - ‘free-form’ Fortran code.
Legal FORTRAN 77 code is also legal fixed-form Fortran 9x; however this change legitimizes the use of later features, in particular to replace - features marked ‘obsolescent’ in Fortran 90 and ‘deleted’ in Fortran 2018 which gfortran 8.x and later warn about.
Packages containing files in the ‘src’ directory with extensions ‘.f90’ or ‘.f95’ are now linked using the C or C++ compiler rather than the - Fortran 9x compiler. This is consistent with fixed-form Fortran code and allows mixing of C++ and free-form Fortran on most platforms.
Consequentially, a package which includes free-form Fortran 9x code which uses OpenMP should include SHLIB_OPENMP_CFLAGS (or the CXXFLAGS version if they also include C++ code) in PKG_LIBS rather than SHLIB_OPENMP_FCFLAGS — fortunately on almost all current platforms they are the - same flag.
Macro PKG_FFLAGS will be used for the compilation of both fixed-form and free-form Fortran code unless PKG_FCFLAGS is also set (in ‘src/- Makevars’ or ‘src/Makevars.win’).
- The make macro F_VISIBILITY is now preferred for both fixed-form and free-form Fortran, for use in ‘src/Makevars’ and similar.
R CMD INSTALL gains a new option --strip which (where supported) strips installed shared object(s): this can also be achieved by setting the - environment variable _R_SHLIB_STRIP_ to a true value.
- The new option --strip-lib attempts stripping of static and shared libraries installed under ‘lib’.
- These are most useful on platforms using GNU binutils (such as Linux) and compiling with -g flags.
There is more support for installing UTF-8-encoded packages in a strict Latin-1 locale (and probably for other Latin locales): non-ASCII - comments in R code (and ‘NAMESPACE’ files) are worked around better.

UTILITIES:
- R CMD check now optionally checks makefiles for correct and portable use of the SHLIB_OPENMP_*FLAGS macros.
R CMD check now evaluates Sexpr{} expressions (including those in macros) before checking the contents of ‘Rd’ files and so detects issues both - in evaluating the expressions and in the expanded contents.
R CMD check now lists missing packages separated by commas and with regular quotes such as to be useful as argument in calling install.packages(- c(..)); from a suggestion by Marcel Ramos.
- tools::Rd2latex() now uses UTF-8 as its default output encoding.
R CMD check now checks line endings of files with extension ‘.hpp’ and those under ‘inst/include’. The check now includes that a non-empty file - is terminated with a newline.
- R CMD build will correct line endings in such files.
R CMD check now tries re-building all vignettes rather than stopping at the first error: whilst doing so it adds ‘bookmarks’ to the log. By - default (see the ‘R Internals’ manual) it re-builds each vignette in a separate process.
It now checks for duplicated vignette titles (also known as ‘index entries’): they are used as hyperlinks on CRAN package pages and so do need - to be unique.
- R CMD check has more comprehensive checks on the ‘data’ directory and the functioning of data() in a package.
R CMD check now checks autoconf-generated ‘configure’ files have their corresponding source files, including optionally attempting to regenerate - them on platforms with autoreconf.
- R CMD build has a new option --compression to select the compression used for the tarball.
- R CMD build now removes ‘src/*.mod’ files on all platforms.

C-LEVEL FACILITIES:
New pointer protection C functions R_PreserveInMSet and R_ReleaseFromMSet have been introduced to replace UNPROTECT_PTR, which is not safe to - mix with UNPROTECT (and with PROTECT_WITH_INDEX). Intended for use in parsers only.
NAMEDMAX has been raised to 7 to allow further protection of intermediate results from (usually ill-advised) assignments in arguments to BUILTIN - functions. Properly written package code should not be affected.
- R_unif_index is now considered to be part of the C API.
- R_GetCurrentEnv() allows C code to retrieve the current environment.

DEPRECATED AND DEFUNCT:
Argument compressed of untar() is deprecated — it is only used for external tar commands which increasingly for extraction auto-detect - compression and ignore their zjJ flags.
- var(f) and hence sd(f) now give an error for factor arguments; they gave a deprecation warning since R 3.2.3, PR#16564.
Package tools' vignetteDepends() has been deprecated (it called a function deprecated since Feb 2016), being partly replaced by newly exported - vignetteInfo().
- The f77_f2c script has been removed: it no longer sufficed to compile the ‘.f’ files in R.
- The deprecated legacy support of make macros such as CXX1X has been removed: use the CXX11 forms instead.
- Make macro F77_VISIBILITY is deprecated in favour of F_VISIBILITY.
- Make macros F77, FCPIFCPLAGS and SHLIB_OPENMP_FCFLAGS are deprecated in favour of FC, FPICFLAGS and SHLIB_OPENMP_FFLAGS respectively.
$.data.frame had become an expensive version of the default method, so has been removed. (Thanks to Radford Neal for picking this up and to - Duncan Murdoch for providing a patch.)

BUG FIXES:
replayPlot(r) now also works in the same R session when r has been “reproduced” from serialization, typically after saving to and reading from - an RDS file.
- substr() and substring() now signal an error when the input is invalid UTF-8.
- file.copy() now works also when its argument to is of length greater than one.
- mantelhaen.test() no longer suffers from integer overflow in largish cases, thanks to Ben Bolker's PR#17383.
- Calling setGeneric("foo") in a package no longer fails when the enclosing environment of the implicit generic foo() is .GlobalEnv.
- untar(file(".tar.gz"), *) now gives a better error message, suggesting to use gzfile() instead.
- Method dispatch uses more relevant environments when looking up class definitions.
The documentation for identify() incorrectly claimed that the indices of identified points were returned in the order that the points were selected. identify() now has a new argument order to allow the return value to include the order in which points were identified; the - documentation has been updated. Reported by Richard Rowe and Samuel Granjeaud.
- order(...., decreasing=c(TRUE, FALSE)) could fail in some cases. Reported from StackOverflow via Karl Nordström.
- User macros in Rd files now accept empty and multi-line arguments.
- Calling install.packages() with a length zero pkgs argument now is a no-op (PR#17422).
- unlist(x) now returns a correct factor when x is a nested list with factor leaves, fixing PR#12572 and PR#17419.
- The documentation help(family) gives more details about the aic component, thanks to Ben Bolker's prompting.
The documentation for attributes and `attributes<-` now gives x as name of the first and main argument which the implementation has been - requiring, fixing PR#17434. For consistency, the first argument name is also changed from obj to x for `mostattributes<-`.
- strwidth() now uses par("font") as default font face (PR#17352).
- plot(, log="x") no longer warns about log.The print() method for "htest" objects now formats the test statistic and parameter directly and hence no longer rounds to units before the decimal point. Consequently, printing of t.test() results with a small number of digits now shows non-large df's to the full precision (- PR#17444).- kruskal.test() and fligner.test() no longer erroneously insist on numeric g group arguments (PR#16719).- Printing a news db via the browser now does a much better job (PR#17433).- print.aov() missed column names in the multivariate case due to misspelling (reported by Chris Andrews).- axis() now creates valid at locations also for small subnormal number ranges in log scale plots.format.POSIXlt() now also recycles the zone and gmtoff list components to full length when needed, and its internal C code detects have_zone in - more cases. In some cases, this changes its output to become compatible with format.POSIXct().On Windows, detectCores() in package parallel now detects processors in all processor groups, not just the group R is running in (impacts - particularly systems with more than 64 logical processors). Reported by Arunkumar Srinivasan.On Windows, socketSelect() would hang with more than 64 sockets, and hence parallel::clusterApplyLB() would hang with more than 64 workers. - Reported by Arunkumar Srinivasan.- as(1L, "double") now does coerce (PR#17457).lm.influence(), influence.measures(), rstudent() etc now work (more) correctly for multivariate models ("mlm"), thanks to (anonymous) - stackoverflow remarks.- sample.int(2.9, *, replace=TRUE) again behaves as documented and as in R < 3.0.0, namely identically to sample.int(2, ..).- Fixes to convertColor() for chromatic adaptation; thanks to Brodie Gaslam PR#17473.Using Sexpr[stage=install]{..} to create an ‘Rd’ section no longer gives a warning in R CMD check; problem originally posted by Gábor Csárdi, - then reported as PR#17479 with a partial patch by Duncan Murdoch.- Parse data now include a special node for equal assignment.split.default() no longer relies on [[<-(), so it behaves as expected when splitting an object by a factor with the empty string as one of its - levels. Thanks to Brad Friedman for the report.- Line numbers in messages about ‘.Rd’ files are now more reliable, thanks to a patch from Duncan Murdoch.In the numeric method for all.equal(), a numeric scale argument is now checked to be positive and allowed to be of length > 1. (The latter - worked originally and with a warning in recent years).- Deferred string conversions now record the OutDec option setting when not equal to the default. Reported by Michael Sannella.When y is numeric and f a factor, plot(y ~ f) nicely uses "y" and "f" as y- and x-labels. The more direct boxplot(y ~ f) now does too. The new - argument ann = FALSE may be used to suppress these.Subassignment to no/empty rows of a data frame is more consistent and typically a no-op in all cases instead of sometimes an error; part of Emil - Bode's PR#17483.Calls like formatC(*, zero.print = "< 0.001") no longer give an error and are further improved via new optional argument replace.zero. Reported - by David Hugh-Jones.- methods::formalArgs("") now finds the same function as formals(""), fixing Emil Bode's PR#17499.- The methods package better handles duplicated class names across packages.- The default method of seq() now avoids integer overflow, thanks to the report and "cumsum" patch of Suharto Anggono's PR#17497.- sub() no longer loses encodings for non-ASCII replacements (PR#17509).- Fix for rotated raster image on X11 device. (Partial fix for PR#17148; thanks to Mikko Korpela).formula(model.frame(frml, ..)) now returns frml in all cases, thanks to Bill Dunlap. The previous behavior is available as - DF2formula(<model.frame>).- ar.ols() also returns scalar var.pred in univariate case (PR#17517).normalizePath() now treats NA path as non-existent and normalizes it to NA. file.access() treats NA file name as non-existent. file.edit() and - connection functions such as file() now treat NA file names as errors.The internal regularize.values() auxiliary of approx(), splinefun() etc now warns again when there are ties and the caller did not specify ties. - Further, it no longer duplicates x and y unnecessarily when x is already sorted (PR#17515).- strtoi("", base) now gives NA on all platforms, following its documentation. Reported by Michael Chirico.In the definition of an S4 class, prototype elements are checked against the slots of the class, with giving a prototype for an undefined slot - now being an error. (Reported by Bill Dunlap.)From setClassUnion(), if environment variable _R_METHODS_SHOW_CHECKSUBCLASSES is set to true, the internal .checkSubclasses() utility prints - debugging info to see where it is used.- max.col(m) with an m of zero columns now returns integer NA (instead of 1).- axTicks() no longer returns small “almost zero” numbers (in exponential format) instead of zero, fixing Ilario Gelmetti's PR#17534.- isSymmetric(matrix(0, dimnames=list("A","b"))) is FALSE again, as always documented.- The cairo_pdf graphics device (and other Cairo-based devices) now clip correctly to the right and bottom border.- There was an off-by-one-pixel bug, reported by Lee Kelvin.as.roman(3) <= 2:4 and all other comparisons now work, as do group "Summary" function calls such as max(as.roman(sample(20))) and as.roman(NA). (- Partly reported by Bill Dunlap in PR#17542.)- reformulate("x", response = "sin(y)") no longer produces extra back quotes, PR#17359, and gains new optional argument env.When reading console input from ‘stdin’ with re-encoding (R --encoding=enc < input) the code on a Unix-alike now ensures that each converted - input line is terminated with a newline even if re-encoding fails.- Class unions are unloaded when their namespace is unloaded (PR#17531, adapted from a patch by Brodie Gaslam).- selectMethod() is robust to ANY-truncation of method signatures (thanks to Herve Pages for the report).- as.matrix.data.frame() now produces better strings from logicals, thanks to PR#17548 from Gabe Becker.- The S4 generic signature of rowSums(), rowMeans(), colSums() and colMeans() is restricted to "x".- match(x, tab) now works for long character vectors x, thanks to PR#17552 by Andreas Kersting.- Changes in print.*(), thanks to Lionel Henry's patches in PR#17398:- Printing lists, pairlists or attributes containing calls with S3 class no longer evaluate those.- Printing S4 objects within lists and pairlists dispatches with show() rather than print(), as with auto-printing.- The indexing tags (names or [[]]) of recursive data structures are now printed correctly in complex cases.- Arguments supplied to print() are now properly forwarded to methods when printing lists, pairlists or attributes containing S3 objects.The print parameters are now preserved when printing S3 objects or deparsing symbols and calls. Previously, printing lists containing S3 objects - or expressions would reset these parameters.- Printing lists, pairlists or attributes containing functions now uses srcref attributes if present.