Document type Tap

one of the few types we have covered completely, I believe :-)

lib/Type/Supply.pod

@@ -59,8 +59,8 @@ called, indicating an erroneous termination of the supply.
 The C<&closing> callback is called when somebody closes the tap (which
 terminates that subscription, but keeps the supply as a whole in tact).
 
-Method C<tap> returns an object of type C<Tap>, on which you can call the
-C<close> method to cancle the subscription.
+Method C<tap> returns an object of type L<Tap|/type/Tap>, on which you can
+call the C<close> method to cancle the subscription.
 
 =head2 method emit
 

lib/Type/Tap.pod

@@ -0,0 +1,64 @@
+=begin pod
+
+=TITLE class Tap
+
+=SUBTITLE A subscription to a supply
+
+    class Tap { ... }
+
+A Tap is a subscription to a L<Supply|/type/Supply>.
+
+    my $s   = Supply.new;
+    my $tap = $s.tap(
+        -> $v { say "the value is $v" },
+        done    => { say "Supply is done" },
+        closing => { say "Tap closed" },
+        quit    => -> $ex { say "Supply finished with error $ex" },
+    );
+
+    # later
+    $tap.close;
+    # or
+    $s.close($tap);
+
+=head1 Methods
+
+=head2 method emit
+
+    method emit(Tap:D:) returns Callable:D
+
+Returns the callback that is called for emitted events.
+
+=head2 method done
+
+    method done(Tap:D:)
+
+Returns the callback that is called on successfully shutting down a channel,
+if any.
+
+=head2 method quit
+
+    method quit(Tap:D:)
+
+Returns the callback that is called on shutting down a channel with error, if
+any.
+
+=head2 method closing
+
+    method closing(Tap:D:)
+
+Returns the callback that is called on closing the tap.
+
+=head2 method supply
+
+    method supply(Tap:D:)
+
+Returns the supply to which the tap belongs.
+
+=head2 method close
+
+    method closing(Tap:D:)
+
+Closes the tap.
+
+=end pod