NAME
Class::XSAccessor - Generate fast XS accessors without runtime compilation
SYNOPSIS
package MyClass;
use Class::XSAccessor
constructor => 'new',
getters => {
get_foo => 'foo', # 'foo' is the hash key to access
get_bar => 'bar',
},
setters => {
set_foo => 'foo',
set_bar => 'bar',
},
accessors => {
foo => 'foo',
bar => 'bar',
},
predicates => {
has_foo => 'foo',
has_bar => 'bar',
};
# The imported methods are implemented in fast XS.
# normal class code here.
DESCRIPTION
Class::XSAccessor implements fast read, write and read/write accessors in XS. Additionally, it can provide predicates such as has_foo()
for testing whether the attribute foo
is defined in the object. It only works with objects that are implemented as ordinary hashes. Class::XSAccessor::Array implements the same interface for objects that use arrays for their internal representation.
Since version 0.10, the module can also generate simple constructors (implemented in XS) for you. Simply supply the constructor => 'constructor_name'
option or the constructors => ['new', 'create', 'spawn']
option. These constructors do the equivalent of the following perl code:
sub new {
my $class = shift;
return bless { @_ }, ref($class)||$class;
}
That means they can be called on objects and classes but will not clone objects entirely. Parameters to new()
are added to the object.
The XS accessor methods were between 1.6 and 2.5 times faster than typical pure-perl accessors in some simple benchmarking. The lower factor applies to the potentially slightly obscure sub set_foo_pp {$_[0]->{foo} = $_[1]}
, so if you usually write clear code, a factor of two speed-up is a good estimate.
The method names may be fully qualified. In the example of the synopsis, you could have written MyClass::get_foo
instead of get_foo
. This way, you can install methods in classes other than the current class. See also: The class
option below.
By default, the setters return the new value that was set and the accessors (mutators) do the same. You can change this behaviour with the chained
option, see below. The predicates obviously return a boolean.
OPTIONS
In addition to specifying the types and names of accessors, you can add options which modify behaviour. The options are specified as key/value pairs just as the accessor declaration. Example:
use Class::XSAccessor
getters => {
get_foo => 'foo',
},
replace => 1;
The list of available options is:
replace
Set this to a true value to prevent Class::XSAccessor
from complaining about replacing existing subroutines.
chained
Set this to a true value to change the return value of setters and mutators (when called with an argument). If chained
is enabled, the setters and accessors/mutators will return the object. Mutators called without an argument still return the value of the associated attribute.
As with the other options, chained
affects all methods generated in the same use Class::XSAccessor ...
statement.
class
By default, the accessors are generated in the calling class. Using the class
option, you can explicitly specify where the methods are to be generated.
CAVEATS
Probably wouldn't work if your objects are tied hashes. But that's a strange thing to do anyway.
Scary code exploiting strange XS features.
If you think writing an accessor in XS should be a laughably simple exercise, then please contemplate how you could instantiate a new XS accessor for a new hash key that's only known at run-time. Note that compiling C code at run-time a la Inline::C is a no go.
SEE ALSO
AUTHOR
Steffen Mueller, <smueller@cpan.org>
Chocolateboy, <chocolate@cpan.org>
COPYRIGHT AND LICENSE
Copyright (C) 2008 by Steffen Mueller
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8 or, at your option, any later version of Perl 5 you may have available.