man XML::AutoWriter () - DOCTYPE based XML output


XML::AutoWriter - DOCTYPE based XML output


   use XML::Doctype         NAME => a, SYSTEM_ID => 'a.dtd' ;
   use XML::AutoWriter qw( :all :dtd_tags ) ;
   # a.dtd contains:
   #   <!ELEMENT a ( b1, b2?, b3* ) >
   #      <!ATTLIST   a aa1 CDATA       #REQUIRED >
   #   <!ELEMENT b1 ( c1 ) >
   #   <!ELEMENT b2 ( c2 ) >
   b1 ;                # Emits <a><b1>
   c2( attr=>"val" ) ; # Emits </b1><b2><c2 attr="val">
   endAllTags ;        # Emits </c2></b2></a>

   ## If you've got an XML::Doctype object handy:
   use XML::AutoWriter qw( :dtd_tags ), DOCTYPE => $doctype ;

   ## If you've saved a preparsed DTD as a perl module
   use FooML::Doctype::v1_0001 ;
   use XML::AutoWriter qw( :dtd_tags ) ;

   ## Or as a normal perl object:
   $writer = XML::AutoWriter->new( ... ) ;
   $writer->startTag( 'b1' ) ;
   $writer->startTag( 'c2' ) ;
   $writer->end ;


Alpha. Use and patch, don't depend on things not changing drastically.

Many methods supplied by XML::Writer are not yet supplied here.


This module subclasses XML::ValidWriter and provides automatic start and end tag generation, allowing you to emit only the 'important' tags.

See XML::ValidWriter for the details on all functions not documented here.

XML::Writer API compatibility

Much of the interface is patterned after XML::Writer so that it can possibly be used as a drop-in replacement. It will take awhile before this module emulates enough of XML::Writer to be a drop-in replacement in situations where the more advanced XML::Writer methods are used.

Automatic start tags

Automatic start tag creation is done when emitting a start tag that is not allowed to be a child of the currently open tag but is allowed to be contained in the currently open tag's subset. In this case, the minimal number of start tags necessary to allow All start tags between the current tag and the desired tag are automatically emitted with no attributes.

Automatic end tags

If start tag autogeneration fails, then end tag autogeneration is attempted. startTag() scans the stack of currently open tags trying to close as few as possible before start tag autogeneration suceeds.

Explicit end tags may be emitted to prevent unwanted automatic start tags, and, in the future, warnings or errors will be available in place of automatic start and end tag creation.


All of the routines in this module can be called as either functions or methods unless otherwise noted.

To call these routines as functions use either the DOCTYPE or :dtd_tags options in the parameters to the use statement:

   use XML::AutoWriter DOCTYPE => XML::Doctype->new( ... ) ;
   use XML::AutoWriter qw( :dtd_tags ) ;

This associates an XML::AutoWriter and an XML::Doctype with the package. These are used by the routines when called as functions.

   $writer = XML::AutoWriter->new( DTD => $dtd, OUTPUT => \*FH ) ;
Creates an XML::AutoWriter. All other parameters are passed to the XML::ValidWriter base class constructor.
   characters( 'yabba dabba dooo' ) ;
   $writer->characters( 'yabba dabba dooo' ) ;
If the currently open tag cannot contain #PCDATA, then start tag autogeneration will be attempted, followed by end tag autogeneration. Start tag autogeneration takes place even if you pass in only '', or even (), the empty list.
   endTag ;
   endTag( 'a' ) ;
   $writer->endTag ;
   $writer->endTag( 'a' ) ;
Prints one or more end tags. The tag name is optional and defaults to the most recently emitted start tag if not present. This will emit as many close tags as necessary to close the supplied tag name, or will emit an error if the tag name specified is not open in the output document.
   startTag( 'a', attr => val ) ;  # use default XML::AutoWriter for
                                   # current package.
   $writer->startTag( 'a', attr => val ) ;
Emits a named start tag with optional attributes. If the named tag cannot be a child of the most recently started tag, then any tags that need to be opened between that one and the named tag are opened. If the named tag cannot be enclosed within the most recently opened tag, no matter how deep, then startTag() tries to end as few started tags as necessary to allow the named tag to be emitted within a tag already on the stack. This warns (once) if no <?xml?> declaration has been emitted. It does not check to see if a <!DOCTYPE...> has been emitted. It dies if an attempt is made to emit a second root element.


Barrie Slaymaker <>


This module is Copyright 2000, Barrie Slaymaker. All rights reserved. This module is licensed under the GPL, version 2. Please contact me if this does not suit your needs.