GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  DATA::STAG::BASEGENERATOR (3)

.ds Aq ’

NAME



  Data::Stag::BaseGenerator     - base class for parsers and other event generators



CONTENTS

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
Search for    or go to Top of page |  Section 3 |  Main Index


perl v5.20.3 DATA::STAG::BASEGENERATOR (3) 2013-09-18

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.