Em Seg, 2009-02-16 às 17:28 +1100, Timothy S. Nelson escreveu:
> Say I wanted to write a POP3 server. I want to receive a username and
> password from the client. I want things to be interruptable during this, but
> it's also impossible to sensibly roll things back like they were before the
> connection was opened. Is this possible with the concurrency model you
> specified?
The things you're describing are from the time when we were assuming STM
(Software Transactional Memory) would be used by every implementation of
Perl 6. Things have changed a bit in the last months, as STM seems a bit
more challenging then it looks at first sight for a language as complex
as Perl 6, specially if you think about lazyness.
OTOH, the problem POE solves is the lack of a good "green threads"
implementation in perl 5, which I think is not a problem for Perl 6 (I
can say that for sure about SMOP, but I'm pretty sure that is also valid
for parrot).
In that specific area of writing network servers, I've been with a fixed
idea about providing autothreading code, so you can write code that
looks like 'imperative block-wait programming', but is actually 'async
non-blocking programming'. I'll paste my last sketch about it here:
my $io = Net::TCP.listen(:host<localhost>, :port(1234));
$io does IO::Async[EV];
$io.accepts: -> $conn {
my %headers;
my $data;
my $waiting_headers = 1;
for =$conn -> $line {
if ($line && $waiting_headers) {
my ($name, $val) = split(/\s*:\s*/, $line);
$headers{$name} = $val;
} elsif ($line) {
$data ~= $line;
} else {
$waiting_headers = 0;
}
}
$conn.write("200 OK\n\nSucessfull request\n");
};
EV.loop;
daniel
