Tk::Eventloop - ToolKit for Events

NAME  SYNOPSIS  DESCRIPTION 

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NAME

Tk::Event − ToolKit for Events

SYNOPSIS

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])

DESCRIPTION

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},$/) < 0)
{
DoOneEvent();
}
Event−>io(*$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.

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