Any Common digit set can match in any script

This fixes a design flaw in script runs that in 5.30 effectively
prevented digits from the Common script except the ASCII [0-9] from
being in any meaningful script run.

2 files changed, 26 insertions, 14 deletions

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 3a40c91660..471fe4c2a6 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -14,9 +14,19 @@ L<perl5281delta>, which describes differences between 5.28.0 and 5.28.1.
 
 =head1 Incompatible Changes
 
-There are no changes intentionally incompatible with 5.28.1.  If any exist,
-they are bugs, and we request that you submit a report.  See L</Reporting
-Bugs> below.
+=head2 Any set of digits in the Common script are legal in a script run
+of another script
+
+There are several sets of digits in the Common script.  C<[0-9]> is the
+most familiar.  But there are also C<[\x{FF10}-\x{FF19}]> (FULLWIDTH
+DIGIT ZERO - FULLWIDTH DIGIT NINE), and several sets for use in
+mathematical notation, such as the MATHEMATICAL DOUBLE-STRUCK DIGITs.
+Any of these sets should be able to appear in script runs of, say,
+Greek.  But the design of 5.30 overlooked all but the ASCII digits
+C<[0-9]>, so the design was flawed.  This has been fixed, so is both a
+bug fix and an incompatibility. [perl #133547]
+
+All digits in a run still have to come from the same set of ten digits.
 
 =head1 Modules and Pragmata
 
@@ -113,6 +123,11 @@ perl if compilation continued.
 
 L<[perl #132158]|https://rt.perl.org/Ticket/Display.html?id=132158>
 
+=item *
+
+See L</Any set of digits in the Common script are legal in a script run
+of another script>.
+
 =back
 
 =head1 Acknowledgements
diff --git a/pod/perlre.pod b/pod/perlre.pod
index 70c53f1536..c587437c75 100644
--- a/pod/perlre.pod
+++ b/pod/perlre.pod
@@ -2529,15 +2529,12 @@ characters from their native scripts and base Chinese.  Perl follows
 Unicode's UTS 39 (L<http://unicode.org/reports/tr39/>) Unicode Security
 Mechanisms in allowing such mixtures.
 
-The rules used for matching decimal digits are somewhat different.  Many
+The rules used for matching decimal digits are slightly stricter.  Many
 scripts have their own sets of digits equivalent to the Western C<0>
 through C<9> ones.  A few, such as Arabic, have more than one set.  For
 a string to be considered a script run, all digits in it must come from
-the same set, as determined by the first digit encountered. The ASCII
-C<[0-9]> are accepted as being in any script, even those that have their
-own set.  This is because these are often used in commerce even in such
-scripts.  But any mixing of the ASCII and other digits will cause the
-sequence to not be a script run, failing the match.  As an example,
+the same set of ten, as determined by the first digit encountered.
+As an example,
 
  qr/(*script_run: \d+ \b )/x
 
@@ -2558,11 +2555,11 @@ accent of some type.  These are considered to be in the script of the
 master character, and so never cause a script run to not match.
 
 The other one is "Common".  This consists of mostly punctuation, emoji,
-and characters used in mathematics and music, and the ASCII digits C<0>
-through C<9>.  These characters can appear intermixed in text in many of
-the world's scripts.  These also don't cause a script run to not match,
-except any ASCII digits encountered have to obey the decimal digit rules
-described above.
+and characters used in mathematics and music, the ASCII digits C<0>
+through C<9>, and full-width forms of these digits.  These characters
+can appear intermixed in text in many of the world's scripts.  These
+also don't cause a script run to not match.  But like other scripts, all
+digits in a run must come from the same set of 10.
 
 This construct is non-capturing.  You can add parentheses to I<pattern>
 to capture, if desired.  You will have to do this if you plan to use