with - Lexically call methods with a default object.
VERSION
- Version 0.01
+ Version 0.03
+
+WARNING
+ This module was an early experiment which turned out to be completely
+ unpractical. Therefore its use is officially deprecated. Please don't
+ use it, and don't hesitate to contact me if you want to reuse the
+ namespace.
SYNOPSIS
package Deuce;
sub hlagh { my $self = shift; print "Deuce::hlagh $self->{id}\n" }
+
package Pants;
sub hlagh { print "Pants::hlagh\n" }
use with \$deuce;
hlagh; # Deuce::hlagh 1
Pants::hlagh; # Pants::hlagh
-
+
{
use with \Deuce->new(2);
hlagh; # Deuce::hlagh 2
will be the last specified one.
HOW DOES IT WORK
- The main problem to address is that lexical scope and source
- modifications can only occur at compile time, while object creation and
+ The main problem to address is that lexical scoping and source
+ modification can only occur at compile time, while object creation and
method resolution happen at run-time.
The "use with \$obj" statement stores an address to the variable $obj in
the "with" field of the hints hash "%^H". It also starts a source filter
that replaces function calls with calls to "with::defer", passing the
name of the original function as the first argument. When the replaced
- function is part of Perl core, the call is deferred to a corresponding
- wrapper generated in the "with" namespace. Some keywords that couldn't
- possibly be replaced are also completely skipped. "no with" undefines
- the hint and deletes the source filter, stopping any subsequent
- modification in the current scope.
+ function has a prototype or is part of the core, the call is deferred to
+ a corresponding wrapper generated in the "with" namespace. Some keywords
+ that couldn't possibly be replaced are also completely skipped. "no
+ with" undefines the hint and deletes the source filter, stopping any
+ subsequent modification in the current scope.
When the script is executed, deferred calls first fetch the default
object back from the address stored into the hint. If the object "->can"
namespace is inspected for a subroutine with the proper name, and if
it's present the program "goto"s into it. If that fails too, the core
function with the same name is recalled if possible, or an "Undefined
- subroutine" warning is thrown.
+ subroutine" error is thrown.
IGNORED KEYWORDS
- A call will never dispatch to methods whose name is part of :
+ A call will never be dispatched to a method whose name is one of :
my our local sub do eval goto return
- if else elsif unless given when or and
+ if else elsif unless given when or and
while until for foreach next redo last continue
- eq ne lt gt le ge
+ eq ne lt gt le ge cmp
map grep system exec sort print say
new
STDIN STDOUT STDERR
Don't put anything on the same line of "use with \$obj" or "no with".
+ When there's a function in the caller namespace that has a core function
+ name, and when no method with the same name is present, the ambiguity is
+ resolved in favor of the caller namespace. That's different from the
+ usual perl semantics where "sub push; push @a, 1" gets resolved to
+ CORE::push.
+
+ If a method has the same name as a prototyped function in the caller
+ namespace, and if a called is deferred to the method, it will have its
+ arguments passed by value.
+
DEPENDENCIES
perl 5.9.4.
AUTHOR
Vincent Pit, "<perl at profvince.com>", <http://www.profvince.com>.
- You can contact me by mail or on #perl @ FreeNode (vincent or
- Prof_Vince).
+ You can contact me by mail or on "irc.perl.org" (vincent).
BUGS
Please report any bugs or feature requests to "bug-with at rt.cpan.org",
order to add hints support and more placeholder patterns.
COPYRIGHT & LICENSE
- Copyright 2008 Vincent Pit, all rights reserved.
+ Copyright 2008,2017 Vincent Pit, all rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
projects / perl / modules / with.git / blobdiff