New plugin: beep on error

If you computer beeps, that is. Most revbank setups run on raspberry pi's,
which don't beep...

plugins/beep

@@ -0,0 +1,17 @@
+#!perl
+
+sub command { NEXT }
+
+*hook_plugin_fail = *hook_retry = *hook_reject = *hook_invalid_input = sub {
+    call_hooks('beep');
+    undef;
+};
+
+sub hook_abort {
+    my ($self, $cart, $reason) = @_;
+    return if not $reason or not @$reason;
+    return if "@$reason" eq '^C';
+
+    call_hooks('beep');
+    undef;
+}

revbank

@@ -139,7 +139,7 @@ OUTER: for (;;) {
         print @_, " " if @_;
         @words = ();
         @retry = ();
-        call_hooks "abort", $cart;
+        call_hooks "abort", $cart, \@_;
         $cart->empty;
         { no warnings; redo OUTER; }
     }

revbank.plugins

@@ -3,6 +3,7 @@
 # First, plugins with no commands, or very specific commands
 
 log        # first, so that the registrations of other plugins are logged
+beep
 sigint
 restart
 help