NAME
Alt::IO::All::new - Alternate IO::All - The Rewrite
SYNOPSIS
> cpanm Alt::IO::All::new
use IO::All;
DESCRIPTION
This is a rewrite of the infamous IO::All. The new design is detailed
below.
STATUS
This is a very early release. It's just barely operational. Enough to
upload to CPAN under the new experimental "Alt-" namespace.
"IO::ALL" DESIGN
This is a design document for an upcoming version of IO::All.
IO::All is a Perl module that attempts to make all Input/Output
operations in Perl, as simple and normal as possible. IO::All has been
in existence since 2005. It is useful and somewhat extensible, but has a
number of inconsistencies, flaws and misgivings.
This document will propose a better way to do it, and will also discuss
how to move the current API forward to the new API.
BASIC PRINCIPLES OF HOW "IO::ALL" SHOULD WORK
* IO::All provides a single entry point function called "io".
* "use IO::All" should make this function available in a lexical
scope.
* Currently this scope is 'package' scope.
* Would be nice, but maybe not possible to have true lexical
scope.
* The "io" function is custom to its scope
* The behavior it provides depends on the state of the scope
* The behavior it provides also depends on the arguments passed to
"use IO::All"
* "io" returns an IO::All object
* The IO::All object has no I/O capabilities
* Further method calls invoke a context, causing the IO::All
object to rebless itself it something useful like IO::All::File.
* Certain methods force a rebless
* `file(...), dir(...), socket(...), etc
* These methods are more or less hard-coded currently
* Options to "use IO::All" that begin with a "-", cause a method to be
called on each new IO::All object.
* use IO::All -strict, -encoding => 'big5'; # causes:
* io('foo')->print('hi'); # to mean:
* io('foo')->strict->encoding('big5')->print('hi');
* IO::All operations generally return other IO::All objects
* Often they return themselves ($self) for chaining
* IO::All needs to be completely and consistently extensible
* The extensions that ship with IO-All should be the same as third
party extensions
* Plugins register capabilities with IO::All (tied to a scope)
* IO::All operations can be strict or loose. Strict always throws
errors on any possible error condition. Strict or loose should be
determined by the presence of "use strict" in the scope (possibly).
* IO::All currently uses a big set of overloaded operations by
default. This is loved by some and hated by others. It should
probably be off by default for 2.0.
"IO::ALL" PLUGINS
Currently the extension API is fairly muddy. I would like the new API to
require something like this:
{
use strict;
use IO::All -overload;
use IO::All::PrintingPress;
my $io = io('path:to:printing:press#1');
# is ref($io), 'IO::All';
$io->print('IO::All'); # calls IO::All::PrintingPress::print
# is ref($io), 'IO::All::PrintingPress';
}
So you need to load any extensions that you want to use, within the
scope that you want them in. Exceptions are IO::All::File and
IO::All::Dir, which are automatically loaded, unless you say:
use IO::All -none;
Plugins can register 3 things:
* Register a method (or methods) that will force a rebless in that
class.
* Register a regexp (or function) that will cause a rebless when the
input to io(...) matches.
* Register overloads that the plugin responds to.
These things are register according to the scope of the IO::All, so that
the "io" function will do the right things.
Transition to the new API
It needs to be determined if the changes that need to be made are too
destructive to coexist with the current IO::All. That determination
obviously cannot be made until the new design is complete.
If it is not too destructive, IO::All and its extensions can be brought
forward.
If it is too destructive, here is one proposed solution:
Support IO::All 2 <options>;
The version '2' will load IO::All2 (or something) and no version will
load the old code.
It is important to assure that the old and new interfaces can coexist in
the same process space.
In the IO::All2 scenario, we would need to figure out if the current
IO::All extensions also needed forwarding.
SEE ALSO
* Alt
* IO::All
AUTHOR
Ingy döt Net <ingy@cpan.org>
COPYRIGHT
Copyright 2012-2014. Ingy döt Net.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See <http://www.perl.com/perl/misc/Artistic.html>