Created
October 23, 2011 08:42
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A perl implementation of http://drum.lib.umd.edu/bitstream/1903/8400/1/tr.pdf
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use strict; | |
use warnings; | |
{ | |
package AsyncArrow; | |
use Scalar::Util qw/weaken/; | |
use AnyEvent; | |
use Exporter qw/import/; | |
use Class::Accessor::Lite new => 1, rw => ['code']; | |
our @EXPORT = qw/repeat done/; | |
sub repeat_request(;$) { {repeat => 1, value => shift} } | |
sub done_request(;$) { {done => 1, value => shift} } | |
sub arr { | |
my ($class, $f) = @_; | |
$class->new(code => sub { | |
my ($v, $progress, $cont) = @_; | |
$cont->($f->($v), $progress); | |
}); | |
} | |
sub compose { | |
my ($self, $other) = @_; | |
return (ref $self)->new(code => sub { | |
my ($v, $progress, $cont) = @_; | |
$self->code->($v, $progress, sub { | |
my ($v, $progress) = @_; | |
$other->code->($v, $progress, $cont); | |
}); | |
}); | |
} | |
sub run { | |
my ($self, $v, $progress) = @_; | |
$progress ||= ProgressArrow->new_without_args; | |
$self->code->($v, $progress, sub { | |
my ($v, $progress) = @_; | |
return; | |
}); | |
return $progress; | |
} | |
sub repeat { | |
my $self = shift; | |
my $weaken_loop; | |
my $loop = sub { | |
my ($v, $progress, $cont) = @_; | |
$self->code->($v, $progress, sub { | |
my ($v, $progress) = @_; | |
if ($v->{repeat}) { | |
my $canceller; | |
my $t = AE::timer 0, 0, sub { | |
$progress->advance($canceller); | |
$weaken_loop->($v->{value}, $progress, $cont); | |
}; | |
$progress->add_canceller($canceller = sub { undef $t }); | |
} elsif ($v->{done}) { | |
$cont->($v->{value}, $progress); | |
} else { die } | |
}); | |
}; | |
weaken($weaken_loop = $loop); | |
(ref $self)->new(code => $loop); | |
} | |
} | |
{ | |
package ProgressArrow; | |
use parent qw/-norequire AsyncArrow/; | |
use Scalar::Util qw/weaken/; | |
use Class::Accessor::Lite rw => ['cancellers', 'observers']; | |
sub new_without_args { | |
my $class = shift; | |
my $self = $class->new( | |
cancellers => [], | |
observers => [], | |
); | |
weaken(my $weaken_self = $self); | |
$self->code(sub { | |
my ($v, $progress, $cont) = @_; | |
push @{$weaken_self->observers}, sub { | |
my ($v) = @_; | |
$cont->($v, $progress); | |
}; | |
}); | |
return $self; | |
} | |
sub add_canceller { | |
my $self = shift; | |
push @{$self->cancellers}, @_; | |
} | |
sub advance { | |
my ($self, $canceller) = @_; | |
@{$self->cancellers} = grep {$canceller != $_} @{$self->cancellers}; | |
while (my $observer = shift @{$self->observers}) { | |
$observer->(); | |
} | |
} | |
sub cancel { | |
my ($self, $canceller) = @_; | |
while (my $cancel = shift @{$self->cancellers}) { | |
$cancel->(); | |
} | |
} | |
} | |
use AnyEvent; | |
use AnyEvent::Handle; | |
sub inputted_line() { | |
AsyncArrow->new(code => sub { | |
my ($v, $progress, $cont) = @_; | |
my $canceller; | |
my $hdl = AnyEvent::Handle->new( | |
fh => \*STDIN, | |
on_error => sub { | |
my ($hdl, $fatal, $message) = @_; | |
$hdl->destroy; | |
$! and warn "$message(fatal=$fatal)"; | |
$cont->(); | |
}, | |
on_read => sub { | |
my ($hdl) = @_; | |
$hdl->push_read(line => sub { | |
my ($hdl, $line, $eol) = @_; | |
$progress->advance($canceller); | |
$canceller->(); | |
$cont->($line, $progress); | |
}); | |
}, | |
); | |
$progress->add_canceller($canceller = sub { undef $hdl }); | |
}); | |
} | |
my $cv = AE::cv; | |
my $total_length = 0; | |
my $p = inputted_line->compose(AsyncArrow->arr(sub { | |
if (defined $_[0]) { | |
$total_length += length $_[0]; | |
print "INPUT: $_[0]\n"; | |
AsyncArrow::repeat_request; | |
} else { | |
print "DONE\n"; | |
AsyncArrow::done_request; | |
} | |
}))->repeat | |
->compose(AsyncArrow->arr(sub { $cv->send })) | |
->run; | |
$p->compose(AsyncArrow->arr(sub { | |
print "total length: $total_length\n" | |
}))->compose(AsyncArrow->arr(\&AsyncArrow::repeat_request)) | |
->repeat | |
->run; | |
$cv->recv; |
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