char vs U8 warnings

[p5sagit/p5-mst-13.2.git] / pod / perlref.pod

diff --git a/pod/perlref.pod b/pod/perlref.pod
index 12bc581..f738399 100644 (file)
--- a/pod/perlref.pod
+++ b/pod/perlref.pod
@@ -558,29 +558,39 @@ to array indices.  Here is an example:
        print "$k => $v\n";
    }
 
-Perl will raise an exception if you try to delete keys from a pseudo-hash
-or try to access nonexistent fields.  For better performance, Perl can also
+Perl will raise an exception if you try to access nonexistent fields.
+For better performance, Perl can also
 do the translation from field names to array indices at compile time for
 typed object references.  See L<fields>.
 
-There are two ways to check for the existance of a key in a
+There are two ways to check for the existence of a key in a
 pseudo-hash.  The first is to use exists().  This checks to see if the
-given field has been used yet.  It acts this way to match the behavior
+given field has ever been set.  It acts this way to match the behavior
 of a regular hash.  For instance:
 
        $phash = [{foo =>1, bar => 2, pants => 3}, 'FOO'];
        $phash->{pants} = undef;
 
-       exists $phash->{foo};    # true, 'foo' was set in the declaration
-       exists $phash->{bar};    # false, 'bar' has not been used.
-       exists $phash->{pants};  # true, your 'pants' have been touched
+       print exists $phash->{foo};    # true, 'foo' was set in the declaration
+       print exists $phash->{bar};    # false, 'bar' has not been used.
+       print exists $phash->{pants};  # true, your 'pants' have been touched
 
 The second is to use exists() on the hash reference sitting in the
 first array element.  This checks to see if the given key is a valid
 field in the pseudo-hash.
 
-       exists $phash->[0]{bar};        # true, 'bar' is a valid field
-       exists $phash->[0]{shoes};      # false, 'shoes' can't be used
+       print exists $phash->[0]{bar};  # true, 'bar' is a valid field
+       print exists $phash->[0]{shoes};# false, 'shoes' can't be used
+
+delete() on a pseudo-hash element only deletes the value corresponding
+to the key, not the key itself.  To delete the key, you'll have to
+explicitly delete it from the first hash element.
+
+       print delete $phash->{foo};     # prints $phash->[1], "FOO"
+       print exists $phash->{foo};     # false
+       print exists $phash->[0]{foo};  # true, key still exists
+       print delete $phash->[0]{foo};  # now key is gone
+       print $phash->{foo};            # runtime exception
 
 =head2 Function Templates