PATCH [perl #118563]: Fix perldata ident defn

The formal definition of identifiers was missing the fact that every
character in an identifier must match \w.  This also adds some
explanation.

diff --git a/pod/perldata.pod b/pod/perldata.pod
index 8bf3dfd..e46507a 100644 (file)
--- a/pod/perldata.pod
+++ b/pod/perldata.pod
@@ -120,7 +120,13 @@ restrictions.
 If working under the effect of the C<use utf8;> pragma, the following
 rules apply:
 
-    / (?[ ( \p{Word} & \p{XID_Start} ) + [_] ]) \p{XID_Continue}* /x
+    / (?[ ( \p{Word} & \p{XID_Start} ) + [_] ])
+      (?[ ( \p{Word} & \p{XID_Continue} ) ]) *    /x
+
+That is, a "start" character followed by any number of "continue"
+characters.  Perl requires every character in an identifier to also
+match C<\w> (this prevents some problematic cases); and Perl
+additionally accepts identfier names beginning with an underscore.
 
 If not under C<use utf8>, the source is treated as ASCII + 128 extra
 controls, and identifiers should match