pod/perlrecharclass: Document [:blank:], [:ascii:] for C89 platforms

These POSIX classes were introduced in C99, and not all C89 platforms
recognize them.  The behavior there was previously undocumented

diff --git a/pod/perlrecharclass.pod b/pod/perlrecharclass.pod
index b5f621b..861b64a 100644 (file)
--- a/pod/perlrecharclass.pod
+++ b/pod/perlrecharclass.pod
@@ -812,10 +812,27 @@ The POSIX class matches the same as its Full-range counterpart.
 
 =item if locale rules are in effect ...
 
-The POSIX class matches according to the locale, except that
-C<word> uses the platform's native underscore character, no matter what
+The POSIX class matches according to the locale, except:
+
+=over
+
+=item C<word>
+
+also includes the platform's native underscore character, no matter what
 the locale is.
 
+=item C<ascii>
+
+on platforms that don't have the POSIX C<ascii> extension, this matches
+just the platform's native ASCII-range characters.
+
+=item C<blank>
+
+on platforms that don't have the POSIX C<blank> extension, this matches
+just the platform's native tab and space characters.
+
+=back
+
 =item if Unicode rules are in effect ...
 
 The POSIX class matches the same as the Full-range counterpart.