Provided by: perl-tk_804.033-1build1_amd64 bug


       Tk::Event - ToolKit for Events


        use Tk::Event;

        Tk::Event->fileevent(\*FH, 'readable' => callback);

        Tk::Event->lineavail(\*FH, callback);

        use Tk::Event::Signal qw(INT);

        $SIG{'INT'} = callback;

        use Tk::Event::process;

        Tk::Event->proc($pid, callback);

        QueueEvent(callback [, position])


       That is better than nothing but still hard to use. Most scripts want higher level result
       (a line, a "block" of data etc.)

       So it has occured to me that we could use new-ish TIEHANDLE thus:

        my $obj = tie SOMEHANDLE,Tk::Event::IO;

        while (<SOMEHANDLE>)

       Then the READLINE routine registers a callback and looks something like:

        sub READLINE
          my $obj = shift;
          Event->io(*$obj,'readable',sub { sysread(*$obj,${*$obj},1,length(${*$obj}) });
          my $pos;
          while (($pos = index(${*$obj},$/) < 0)
          Event->io(*$obj,'readable',''); # unregister
          $pos += length($/);
          my $result = substr(${*$obj},0,$pos);
          substr(${*$obj},0,$pos) = '';
          return $result;

       This is using the scalar part of the glob representing the _inner_ IO as a buffer in which
       to accumulate chars.