NAME POE::Session::MessageBased - a message-based (not @_ based) POE::Session SYNOPSIS use POE::Kernel; use POE::Session::MessageBased; POE::Session::MessageBased->create ( inline_states => { _start => sub { my $message = shift; print "Started.\n"; $message->kernel->yield( count => 2 ); }, count => sub { my ($message, $count) = @_; print "Counted to $count.\n"; if ($count < 10) { $message->kernel->yield( count => ++$count ); } }, _stop => sub { print "Stopped.\n"; } }, ); POE::Kernel->run(); DESCRIPTION POE::Session::MessageBased exists mainly to replace @_[KERNEL, etc.] with message objects that encapsulate various aspects of each event. It also exists as an exam- ple of a subclassed POE::Session, in case someone wants to create new callback or Session semantics. People generally balk at the @_[KERNEL, etc.] calling con- vention that POE uses by default. The author defends the position that this calling convention is a simple combina- tion of common Perl features. Interested people can read http://poe.perl.org/?POE_FAQ/calling_convention for a more detailed account. Anyway, POE::Session::MessageBased subclasses POE::Session and works almost identically to it. The major change is the way event handlers (states) are called. Inline (coderef) handlers gather their parameters like this. my ($message, @args) = @_; Package and object-oriented handlers receive an additional parameter representing the package or object. This is part of the common calling convention that Perl uses. my ($package, $message, @args) = @_; # Package states. my ($self, $message, @args) = @_; # Object states. The $message parameter is an instance of POE::Session::Message, which is not documented elsewhere. POE::Session::Message encapsulates every POE parameter and provides accessors for them. POE::Session POE::Session::MessageBased ------------------------ ----------------------------------- $_[OBJECT] $package, or $self $_[SESSION] $message->session $_[KERNEL] $message->kernel $_[HEAP] $message->heap $_[STATE] $message->state $_[SENDER] $message->sender $_[CALLER_FILE] $message->caller_file $_[CALLER_LINE] $message->caller_line @_[ARG0..$#_] $message->args (in list context) You do not need to use POE::Session::Message yourself. It is included in POE::Session::MessageBased itself. BUGS $message->args() always returns a list: @_[ARG0..$#_]. It would be nice to return a list reference in scalar con- text. AUTHOR & LICENSE POE::Session::MessageBased is Copyright 2002-2010 by Rocco Caputo. All rights are reserved. POE::Session::Message- Based is free software; you may redistribute it and/or modify it under the same terms as Perl itself. The author may be contacted by e-mail via rcaputo@cpan.org.