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data::stag::basegenerator(3pm) [debian man page]

Data::Stag::BaseGenerator(3pm)				User Contributed Perl Documentation			    Data::Stag::BaseGenerator(3pm)

NAME
Data::Stag::BaseGenerator - base class for parsers and other event generators SYNOPSIS
# writing the parser package MyParser; use base qw(Data::Stag::BaseGenerator); sub parse_fh { my ($self, $fh) = shift; my $lnum = 0; $self->start_event('data'); while (<$fh>) { ++$lnum; $self->line_no($lnum); # do stuff $self->start_event('foo'); # ... $self->event(blah=>5); # if (/incorrect_line/) { $self->parse_err('line not in correct format'); } # ... $self->end_event('foo'); } $self->pop_stack_to_depth(0); } 1; # using the parser my $p = MyParser->new; my $h = MyHandler->new; # see Data::Stag::BaseHandler my $eh = Data::Stag->makehandler; $p->handler($h); $p->errhandler($eh); $p->parse($file); # result tree print $h->stag->xml; # write parse errs on standard err printf *STDERR $p->errhandler->stag->xml; # using the parser from the command line unix> stag-parse.pl -p MyParser -w xml -e err.xml > out.xml # using the parser from the command line via intermediate handler unix> stag-handle.pl -p MyParser -m MyHandler -w xml -e err.xml > out.xml DESCRIPTION
This is the base class for all parsers and event generators parsers/generators take some input (usually a filehandle, but a generator could be a socket listener, for example) and fire stag events stag events are start_event NODENAME evbody DATA end_event NODENAME {optional} event NODENAME DATA These events can be nested/hierarchical If uncaught, these events are stacked into a stag tree, which can be written as xml or one of the other stag formats specialised handlers can be written to catch the events your parser throws For example, you may wish to write a pod parser that generates nested events like this: <pod> <section> <type>head1</type> <name>NAME</name> <text>Data::Stag - Structured Tags datastructures</text> </section> ... </pod> (see the source for Data::Stag::PodParser for details) You can write handlers that take the pod-xml and generate something - for example HTML parsers may encounter unexpected things along the way - they may throw an exception, and fall over - or they may choose to fire an error event. by default, error event streams are diverted to STDERR. You can create your own error handlers PUBLIC METHODS
new Title: new Args: Return: L<Data::Stag::BaseGenerator> Example: CONSTRUCTOR handler Title: handler Function: GET/SET ACCESSOR METHOD Args: handler L<Data::Stag::BaseHandler> optional Return: L<Data::Stag::BaseHandler> Example: $p->handler(MyHandler->new); each parser has a handler - all events generated are passed onto the handler; the default handler simply sits there collecting events errhandler Title: errhandler Function: GET/SET ACCESSOR METHOD Args: handler L<Data::Stag::BaseHandler> optional Return: L<Data::Stag::BaseHandler> Example: $p->errhandler(Data::Stag->makehandler); each parser has an error handler - if the parser encounters things it does not expect, it can pass errors to the errorhandler if no errorhandler is set, an XML event handler that writes to STDERR is used cache_errors Title: cache_errors Args: Return: Example: $p->cache_errors If this is called, all errors will be cached rather than written to STDERR The error list can be accessed like this $p->parse($fn); @errs = $p->errhandler->stag->get_error; parse Example - $parser->parse($file1, $file2); Returns - Args - filenames str-LIST parses a file parse Example - $parser->parse_fh($fh) Returns - Args - fh FILEHANDLE parses an open filehandle PROTECTED METHODS
These methods are only of interest if you are making your own parser/generator class start_event NODENAME evbody DATA end_event NODENAME {optional} event NODENAME DATA SEE ALSO
Data::Stag Data::Stag::BaseHandler perl v5.10.0 2008-06-03 Data::Stag::BaseGenerator(3pm)

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