should allow further optimizations in the future.  It should

help make the internal code easier to maintain.

This change is expected to have almost no impact on packages

using supported coding practices in their C/C++ code.

Perl-like regular expressions, if available.  (On non-Windows

platforms PCRE1 can optionally be used if PCRE2 is not available

at build time.)  The version of PCRE in use can be obtained

) has versions <= 8, PCRE2 versions >= 10.

strongly recommended (preferably version 10.30 or later) as PCRE1

PCRE2 reports errors for some regular expressions that were

accepted by PCRE1.  A hyphen now has to be escaped in a character

class to be interpreted as a literal (unless first or last in the

longer allowed in character classes (PCRE1 treated these as

(which is not back compatible with previous use of an unnamed second

, the utility for the data frame method of

, now works without parsing and explicit evaluation,

starting from Suharto Anggono's suggestion in

defaulting to true.  If set to false, missing

values now propagate into the interpolated values.

The internal traceback object produced when an error is

non-UTF-8 locale the output is marked as UTF-8.

Most functions with file-path inputs will give an explicit

error if a file-path input in a marked encoding cannot be

translated (to the native encoding or in some cases on Windows to

UTF-8), rather than translate to a different file path using

any other non-existent file, often with a warning.

There is a new help document accessed by

about the serialization format of a serialized object.

S3 method lookup now by default skips the elements of the

search path between the global and base environments.

to enable splicing a computed list of values into an

has been extended to handle one-sample and

colours (which are less saturated and have better accessibility

properties).  There are also some new built-in palettes, which

include the old default palette under the name

colours to be selected from any of the built-in palettes.

aspect ratio, fulfilling the wish and extending the proposal of