Teach Perl about Unicode named character sequences

mktables is changed to process the Unicode named sequence file.
charnames.pm is changed to cache the looked-up values in utf8.  A new
function, string_vianame is created that can handle named sequences, as
the interface for vianame cannot.  The subroutine lookup_name() is
slightly refactored to do almost all of the common work for \N{} and the
vianame routines.  It now understands named sequences as created my
mktables..

tests and documentation are added.  In the randomized testing section,
half use vianame() and half string_vianame().

1 files changed, 4 insertions, 4 deletions

diff --git a/pod/perlre.pod b/pod/perlre.pod
index b9216c156c..88089ee1d7 100644
--- a/pod/perlre.pod
+++ b/pod/perlre.pod
@@ -231,7 +231,7 @@ also work:
  \e          escape (think troff)  (ESC)
  \cK         control char          (example: VT)
  \x{}, \x00  character whose ordinal is the given hexadecimal number
- \N{name}    named Unicode character
+ \N{name}    named Unicode character or character sequence
  \N{U+263D}  Unicode character     (example: FIRST QUARTER MOON)
  \o{}, \000  character whose ordinal is the given octal number
  \l          lowercase next char (think vi)
@@ -316,9 +316,9 @@ See L</Extended Patterns> below for details.
 =item [7]
 
 Note that C<\N> has two meanings.  When of the form C<\N{NAME}>, it matches the
-character whose name is C<NAME>; and similarly when of the form
-C<\N{U+I<wide hex char>}>, it matches the character whose Unicode ordinal is
-I<wide hex char>.  Otherwise it matches any character but C<\n>.
+character or character sequence whose name is C<NAME>; and similarly
+when of the form C<\N{U+I<hex>}>, it matches the character whose Unicode
+code point is I<hex>.  Otherwise it matches any character but C<\n>.
 
 =back