XML::Handler::Subs(3)

NAME
XML::Handler::Subs - a PerlSAX handler base class for calling user-defined subs

SYNOPSIS
 use XML::Handler::Subs;

 package MyHandlers;
 use vars qw{ @ISA };

 sub s_NAME { my ($self, $element) = @_ };
 sub e_NAME { my ($self, $element) = @_ };

 $self->{Names};    # an array of names
 $self->{Nodes};    # an array of $element nodes

 $handler = MyHandlers->new();
 $self->in_element($name);
 $self->within_element($name);

DESCRIPTION
"XML::Handler::Subs" is a base class for PerlSAX handlers. "XML::Handler::Subs" is subclassed to implement complete behavior and to add element-specific handling.

Each time an element starts, a method by that name prefixed with `s_' is called with the element to be processed. Each time an element ends, a method with that name prefixed with `e_' is called. Any special characters in the element name are replaced by underscores.

Subclassing XML::Handler::Subs in this way is similar to XML::Parser's Subs style.

XML::Handler::Subs maintains a stack of element names, `"$self-"{Names}', and a stack of element nodes, `"$self-"{Nodes}>' that can be used by subclasses. The current element is pushed on the stacks before calling an element-name start method and popped off the stacks after calling the element-name end method. The `in_element()' and `within_element()' calls use these stacks.

If the subclass implements `start_document()', `end_document()', `start_element()', and `end_element()', be sure to use `"SUPER::"' to call the the superclass methods also. See perlobj(1) for details on SUPER::. `SUPER::start_element()' and `SUPER::end_element()' return 1 if an element-name method is called, they return 0 if no method was called.

XML::Handler::Subs does not implement any other PerlSAX handlers.

XML::Handler::Subs supports the following methods:

new( OPTIONS )
    A basic `new()' method. `new()' takes a list of key, value pairs or a hash and creates and returns a hash with those options; the hash is blessed into the subclass.

in_element($name)
    Returns true if `$name' is equal to the name of the innermost currently opened element.

within_element($name)
    Returns the number of times the `$name' appears in Names.

AUTHOR
Ken MacLeod, ken@bitsko.slc.ut.us

SEE ALSO
perl(1), PerlSAX.pod(3)