Provided by: liblucy-perl_0.3.3-8_amd64
NAME
Lucy::Object::Obj - Base class for all Lucy objects.
SYNOPSIS
package MyObj; use base qw( Lucy::Object::Obj ); # Inside-out member var. my %foo; sub new { my ( $class, %args ) = @_; my $foo = delete $args{foo}; my $self = $class->SUPER::new(%args); $foo{$$self} = $foo; return $self; } sub get_foo { my $self = shift; return $foo{$$self}; } sub DESTROY { my $self = shift; delete $foo{$$self}; $self->SUPER::DESTROY; }
DESCRIPTION
All objects in the Lucy:: hierarchy descend from Lucy::Object::Obj. All classes are implemented as blessed scalar references, with the scalar storing a pointer to a C struct. Subclassing The recommended way to subclass Lucy::Object::Obj and its descendants is to use the inside-out design pattern. (See Class::InsideOut for an introduction to inside-out techniques.) Since the blessed scalar stores a C pointer value which is unique per-object, $$self can be used as an inside-out ID. # Accessor for 'foo' member variable. sub get_foo { my $self = shift; return $foo{$$self}; } Caveats: • Inside-out aficionados will have noted that the "cached scalar id" stratagem recommended above isn't compatible with ithreads -- but Lucy doesn't support ithreads anyway, so it doesn't matter. • Overridden methods must not return undef unless the API specifies that returning undef is permissible. (Failure to adhere to this rule currently results in a segfault rather than an exception.)
CONSTRUCTOR
new() Abstract constructor -- must be invoked via a subclass. Attempting to instantiate objects of class "Lucy::Object::Obj" directly causes an error. Takes no arguments; if any are supplied, an error will be reported.
DESTRUCTOR
DESTROY All Lucy classes implement a DESTROY method; if you override it in a subclass, you must call "$self->SUPER::DESTROY" to avoid leaking memory.
ABSTRACT METHODS
to_i64() Convert the object to a 64-bit integer. to_f64() Convert the object to a double precision floating point number. load(dump) Create an object from the output of a call to dump(). Implementations must not reference the caller. • dump - The output of dump().
METHODS
to_string() Generic stringification: "ClassName@hex_mem_address". equals(other) Indicate whether two objects are the same. By default, compares the memory address. • other - Another Obj. dump() Return a representation of the object using only scalars, hashes, and arrays. Some implementations support JSON serialization via dump() and its companion method, load(); for others, dump() is only a debugging aid. The default simply calls to_string().