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=head1 NAME |
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|
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Coro - create and manage coroutines |
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|
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=head1 SYNOPSIS |
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|
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use Coro; |
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|
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$new = new Coro sub { |
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print "in coroutine, switching back\n"; |
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$Coro::main->resume; |
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print "in coroutine again, switching back\n"; |
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$Coro::main->resume; |
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}; |
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|
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print "in main, switching to coroutine\n"; |
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$new->resume; |
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print "back in main, switch to coroutine again\n"; |
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$new->resume; |
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print "back in main\n"; |
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|
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=head1 DESCRIPTION |
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|
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This module implements coroutines. Coroutines, similar to continuations, |
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allow you to run more than one "thread of execution" in parallel. Unlike |
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threads this, only voluntary switching is used so locking problems are |
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greatly reduced. |
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|
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Although this is the "main" module of the Coro family it provides only |
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low-level functionality. See L<Coro::Process> and related modules for a |
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more useful process abstraction including scheduling. |
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|
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=over 4 |
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|
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=cut |
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|
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package Coro; |
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|
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BEGIN { |
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$VERSION = 0.03; |
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|
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require XSLoader; |
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XSLoader::load Coro, $VERSION; |
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} |
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|
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=item $main |
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|
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This coroutine represents the main program. |
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|
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=item $current |
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|
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The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
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|
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=cut |
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|
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$main = $current = _newprocess { |
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# never being called |
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}; |
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|
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=item $error, $error_msg, $error_coro |
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|
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This coroutine will be called on fatal errors. C<$error_msg> and |
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C<$error_coro> return the error message and the error-causing coroutine, |
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respectively. |
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|
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=cut |
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|
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$error_msg = |
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$error_coro = undef; |
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|
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$error = _newprocess { |
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print STDERR "FATAL: $error_msg\nprogram aborted\n"; |
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exit 250; |
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}; |
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|
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=item $coro = new $coderef [, @args] |
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|
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Create a new coroutine and return it. The first C<resume> call to this |
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coroutine will start execution at the given coderef. If it returns it |
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should return a coroutine to switch to. If, after returning, the coroutine |
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is C<resume>d again it starts execution again at the givne coderef. |
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|
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=cut |
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|
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sub new { |
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my $class = $_[0]; |
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my $proc = $_[1]; |
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bless _newprocess { |
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do { |
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eval { &$proc->resume }; |
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if ($@) { |
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($error_msg, $error_coro) = ($@, $current); |
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$error->resume; |
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} |
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} while (1); |
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}, $class; |
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} |
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|
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=item $coro->resume |
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|
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Resume execution at the given coroutine. |
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|
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=cut |
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|
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my $prev; |
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|
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# I call the _transfer function from a pelr function |
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# because that way perl saves all important things on |
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# the stack. |
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sub resume { |
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$prev = $current; $current = $_[0]; |
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_transfer($prev, $current); |
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} |
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|
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1; |
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|
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=back |
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|
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=head1 BUGS |
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|
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This module has not yet been extensively tested. |
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|
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=head1 SEE ALSO |
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|
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L<Coro::Process>, L<Coro::Signal>. |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <pcg@goof.com> |
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http://www.goof.com/pcg/marc/ |
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|
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=cut |
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|
