Make /[\N{}-\N{}]/ match Unicodely on EBCDIC

This makes [\N{U+06}-\N{U+09}] match U+06, U+07, U+08, U+09 even on
EBCDIC platforms, allowing one to write portable ranges.  For 1047
EBCDIC this would match 0x2E, 0x2F, 0x16, and 0x05.

Thanks to Yaroslave Kuzmin for finding a bug in an earlier incarnation
of this patch.

2 files changed, 23 insertions, 5 deletions

diff --git a/pod/perlre.pod b/pod/perlre.pod
index 891eb34644..f11e5ff268 100644
--- a/pod/perlre.pod
+++ b/pod/perlre.pod
@@ -2312,8 +2312,14 @@ Note also that the whole range idea is rather unportable between
 character sets--and even within character sets they may cause results
 you probably didn't expect.  A sound principle is to use only ranges
 that begin from and end at either alphabetics of equal case ([a-e],
-[A-E]), or digits ([0-9]).  Anything else is unsafe.  If in doubt,
-spell out the character sets in full.
+[A-E]), or digits ([0-9]).  Anything else is unsafe or unclear.  If in
+doubt, spell out the character sets in full.  Specifying the end points
+of the range using the C<\N{...}> syntax, using Unicode names or code
+points makes the range portable, but still likely not easily
+understandable to someone reading the code.  For example,
+C<[\N{U+04}-\N{U+07}]> means to match the Unicode code points
+C<\N{U+04}>, C<\N{U+05}>, C<\N{U+06}>, and C<\N{U+07}>, whatever their
+native values may be on the platform.
 
 Characters may be specified using a metacharacter syntax much like that
 used in C: "\n" matches a newline, "\t" a tab, "\r" a carriage return,
diff --git a/pod/perlrecharclass.pod b/pod/perlrecharclass.pod
index c79c9a0399..fb5868d521 100644
--- a/pod/perlrecharclass.pod
+++ b/pod/perlrecharclass.pod
@@ -608,10 +608,22 @@ Examples:
              #  hyphen ('-'), or the letter 'm'.
  ['-?]       #  Matches any of the characters  '()*+,-./0123456789:;<=>?
              #  (But not on an EBCDIC platform).
-
-Perl guarantees that the ranges C<A-Z>, C<a-z>, C<0-9>, and any
+ [\N{APOSTROPHE}-\N{QUESTION MARK}]
+             #  Matches any of the characters  '()*+,-./0123456789:;<=>?
+             #  even on an EBCDIC platform.
+ [\N{U+27}-\N{U+3F}] # Same. (U+27 is "'", and U+3F is "?"
+
+As the final two examples above show, you can achieve portablity to
+non-ASCII platforms by using the C<\N{...}> form for the range
+endpoints.  These indicate that the specified range is to be interpreted
+using Unicode values, so C<[\N{U+27}-\N{U+3F}]> means to match
+C<\N{U+27}>, C<\N{U+28}>, C<\N{U+29}>, ..., C<\N{U+3D}>, C<\N{U+3E}>,
+and C<\N{U+3F}>, whatever the native code point versions for those are.
+
+Perl also guarantees that the ranges C<A-Z>, C<a-z>, C<0-9>, and any
 subranges of these match what an English-only speaker would expect them
-to match.  That is, C<[A-Z]> matches the 26 ASCII uppercase letters;
+to match on any platform.  That is, C<[A-Z]> matches the 26 ASCII
+uppercase letters;
 C<[a-z]> matches the 26 lowercase letters; and C<[0-9]> matches the 10
 digits.  Subranges, like C<[h-k]>, match correspondingly, in this case
 just the four letters C<"h">, C<"i">, C<"j">, and C<"k">.  This is the