NAME
Syntax::Feature::Sugar::Callbacks - Add sugar for declarative method
callbacks
VERSION
version 0.002
SYNOPSIS
use AnythingExportingMethodModifiers;
use syntax 'sugar/callbacks' => {
-callbacks => {
after => {},
before => {},
around => { -before => ['$orig'] },
},
};
after foo ($n) { $self->something($n) }
before bar ($n) { $self->something($n) }
around baz ($n) { $self->something($self->$orig($n)) }
DESCRIPTION
You probably won't use this extension directly. That's why it doesn't
even have an "import" method. Its main reasoning is the ability to
provide on-the-fly sugar for method declarators, most commonly "before",
"after" and "around". This extension will directly dispatch to the
original subroutine, and requires these to be setup before-hand.
Currently, all callbacks will first receive the name of the declared
method, followed by the code reference.
Note that no cleanup of the original handlers will be performed. This is
up to the exporting library or the user.
METHODS
install
$class->install( %arguments )
Called by syntax (or others) to install this extension into a namespace.
SYNTAX
All declarations must currently be in one of the forms
<keyword> <name> (<signature>) { <body> }
<keyword> <name> { <body> }
The "keyword" is the name of the declared callback. The "name" can
either be an identifier like you'd give to "sub", or a double-quoted
string if you want the name to be dynamic:
after "$name" ($arg) { ... }
The signature, if specified, should be in one of the following forms:
($foo)
($foo, $bar)
($class:)
($class: $foo, $bar)
Variables before ":" will be used as replacement for the invocant.
Parameters specified via "-before" and "-middle" will always be
included.
The statement will automatically terminate after the block. The return
value will be whatever the original callback returns.
You can supply subroutine attributes right before the block.
OPTIONS
-invocant
Defaults to $self, but you might want to change this for very
specialized classes.
-callbacks
This is the set of callbacks that should be setup. It should be a hash
reference using callback names as keys and hash references of options as
values. Possible per-callback options are
"-before"
An array reference of variable names that come before the invocant.
A typical example would be the original code reference in "around"
method modifiers.
"-middle"
An array reference of variable names that come after the invocants,
but before the parameters specified in the signature. Use this if
the code reference declared with the construct will receive a
constant parameter. There is no current way to override this in the
signature on a per-construct basis.
"-default"
An array reference of variable names that are used when no signature
was provided. An empty signature will not lead to the defaults being
used.
"-stmt"
By default, anonymous constructs will not automatically terminate
the statement after the code block. If this option is set to a true
value, all uses of the construct will be terminated.
"-allow_anon"
If set to a true value, anonymous versions of this construct can be
declared. If no name was specified, only the code reference will be
passed on to the callback.
"-only_anon"
If set to a true value, a name will not be expected after the
keyword and before the signature.
SEE ALSO
* syntax
* Devel::Declare
BUGS
Please report any bugs or feature requests to
[email protected] or through the web
interface at:
http://rt.cpan.org/Public/Dist/Display.html?Name=Syntax-Feature-Sugar-Ca
llbacks
AUTHOR
Robert 'phaylon' Sedlacek <
[email protected]>
COPYRIGHT AND LICENSE
This software is copyright (c) 2011 by Robert 'phaylon' Sedlacek.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
