NAME
Class::XSAccessor::Array - Generate fast XS accessors without runtime
compilation
SYNOPSIS
package MyClassUsingArraysAsInternalStorage;
use Class::XSAccessor::Array
constructor => 'new',
getters => {
get_foo => 0, # 0 is the array index to access
get_bar => 1,
},
setters => {
set_foo => 0,
set_bar => 1,
},
accessors => { # a mutator
buz => 2,
},
predicates => { # test for definedness
has_buz => 2,
},
true => [ 'is_token', 'is_whitespace' ],
false => [ 'significant' ];
# The imported methods are implemented in fast XS.
# normal class code here.
DESCRIPTION
The module implements fast XS accessors both for getting at and setting
an object attribute. Additionally, the module supports mutators and
simple predicates ("has_foo()" like tests for definedness of an
attributes). The module works only with objects that are implemented as
arrays. Using it on hash-based objects is bound to make your life
miserable. Refer to Class::XSAccessor for an implementation that works
with hash-based objects.
A simple benchmark showed more than a factor of two performance
advantage over writing accessors in Perl.
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. Note that any parameters to new() will be discarded!
If there is a better idiom for array-based objects, let me know.
While generally more obscure than hash-based objects, objects using
blessed arrays as internal representation are a bit faster as its
somewhat faster to access arrays than hashes. Accordingly, this module
is slightly faster (~10-15%) than Class::XSAccessor, which works on
hash-based objects.
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.
Since version 1.01, you can generate extremely simply methods which
simply return true or false (and always do so). If that seems like a
really superfluous thing to you, then think of a large class hierarchy
with interfaces such as PPI. This is implemented as the "true" and
"false" options, see synopsis.
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::Array
getters => {
get_foo => 0,
},
replace => 1;
The list of available options is:
replace
Set this to a true value to prevent "Class::XSAccessor::Array" 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::Array ..." 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*. 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 or array index that's only known at
run-time. Note that compiling C code at run-time a la Inline::C is a no
go.
Threading. With version 1.00, a memory leak has been fixed that would
leak a small amount of memory if you loaded "Class::XSAccessor"-based
classes in a subthread that hadn't been loaded in the "main" thread
before. If the subthread then terminated, a hash key and an int per
associated method used ot be lost. Note that this mattered only if
classes were only loaded in a sort of throw-away thread.
In the new implementation as of 1.00, the memory will not be released
again either in the above situation. But it will be recycled when the
same class or a similar class is loaded again in any thread.
SEE ALSO
Class::XSAccessor
AutoXS
AUTHOR
Steffen Mueller, <smueller@cpan.org>
COPYRIGHT AND LICENSE
Copyright (C) 2008-2009 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.