-# $Id: ZOOM.pod,v 1.21 2005-12-13 16:22:41 mike Exp $
+# $Id: ZOOM.pod,v 1.23 2005-12-19 17:42:15 mike Exp $
use strict;
use warnings;
=head2 ZOOM::event()
-B<Warning: lark's vomit. Do not read this.>
+B<Warning.>
+Lark's vomit. Do not read this section.
$which = ZOOM::event([ $conn1, $conn2, $conn3 ]);
into the list; 0 is returned if no event occurs within the longest
timeout specified by the C<timeout> options of all the connections.
-B<This function is not yet implemented.>
+B<Warning.>
+This function is not yet implemented.
=head1 CLASSES
a C<ZOOM::Query::PQF> object. See the documentation of that class for
information about PQF.
-=head4 scan()
+=head4 scan() / scan1()
+
+ ### Code sample needed here!
Many Z39.50 servers allow you to browse their indexes to find terms to
search for. This is done using the C<scan> method, which creates and
but overriding this can be useful to get a high-level overview of the
index.
+The C<scan1()> method is the same as C<scan()> except that it takes a
+Query object as its argument instead of a PQF string. This means
+that it can be used to scan using a CQL term, so long as the
+underlying ZOOM-C library supports this.
+
=back
=head4 package()
Returns a C<ZOOM::Event> enumerated value indicating the type of the
last event that occurred on the connection. This is used only in
complex asynchronous applications - see the section below on
-<ZOOM::Event> for more information.
+C<ZOOM::Event> for more information.
-B<Beware - this method has not been tested>
+B<Warning.>
+This method has not been tested.
=head4 destroy()
=head4 set_callback()
-I<###>
+ sub cb {
+ ($udata, $key) = @;
+ return "$udata-$key-$udata";
+ }
+ $o->set_callback(\&cb, "xyz");
+ assert($o->option("foo") eq "xyz-foo-xyz");
+
+This method allows a callback function to be installed in an option
+set, so that the values of options can be calculated algorithmically
+rather than, as usual, looked up in a table. Along with the callback
+function itself, an additional datum is provided: when an option is
+subsequently looked up, this datum is passed to the callback function
+along with the key; and its return value is returned to the caller as
+the value of the option.
+
+B<Warning.>
+Although it ought to be possible to specify callback function using
+the C<\&name> syntax above, or a literal C<sub { code }> code
+reference, the complexities of the Perl-internal memory management
+system mean that the function must currently be specified as a string
+containing the fully-qualified name, e.g. C<"main::cb">.>
+
+B<Warning.>
+The current implementation of the this method leaks memory, not only
+when the callback is installed, but on every occasion that it is
+consulted to look up an option value.
=head4 destroy()