Perl 6 Deep Dive

Closing channels

The close method closes a channel. This means that no more data will be added to it. To check if the channel is closed, call the closed method:

my $channel = Channel.new();say 'Open' unless $channel.closed(); # Open$channel.close();say 'Closed' if $channel.closed();   # Closed

The return value of the closed method is not a Boolean value. Instead, the method returns a promise, which becomes kept after the channel closes:

my $channel = Channel.new();say $channel.closed().status(); # Planned$channel.close();say $channel.closed().status(); # Kept

The promise can be used, for example, to run some code in response to closing a channel, as shown in the following example:

my $channel = Channel.new();my $promise = $channel.closed(); ...