NAME

       tdom::pullparser - Create an XML pull parser command

SYNOPSIS

       package require tdom

           tdom::pullparser cmdName  ? -ignorewhitecdata ?

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DESCRIPTION

       This  command  creates  XML  pull  parser commands with a simple API, along the lines of a
       simple StAX parser. After creation, you've to set an input source, to do  anything  useful
       with the pull parser. For this see the methods input, inputchannel and inputfile.

       The  parser  has  always a state. You start parsing the XML data until some next state, do
       what has to be done and skip again to the next state. XML well-formedness errors along the
       way will be reported as TCL_ERROR with additional info in the error message.

       The  pull  parsers  don't follow external entities and are XML 1.0 only, they know nothing
       about XML Namespaces. You get the tags and attribute names as in the  source.  You  aren't
       noticed  about  comments, processing instructions and external entities; they are silently
       ignored for you. CDATA Sections are handled as if their content would have  been  provided
       without using a CDATA Section.

       On  the  brighter  side is that character entity and attribute default declarations in the
       internal subset are respected (because  of  using  expat  as  underlying  parser).  It  is
       probably  somewhat faster than a comperable implementation with the SAX interface.  It's a
       nice programming model. It's a slim interface.

       If the option -ignorewhitecdata is given, the created XML pull parser command will  ignore
       any  white  space only (' ', \t, \n and \r) text content between START_TAG and START_TAG /
       END_TAG.  The parser won't stop at such input and will create TEXT state events  only  for
       not white space only text.

       Not  all  methods are valid in every state. The parser will raise TCL_ERROR if a method is
       called in a state the method isn't valid for. Valid methods of the created commands are:

       state  This method is valid in all parser states. The possible  return  values  and  their
              meanings are:

              •      READY - The parser is created or reset, but no input is set.

              •      START_DOCUMENT - Input is set, parser is ready to start parsing.

              •      START_TAG - Parser has stopped parsing at a start tag.

              •      END_TAG - Parser has stopped parsing at an end tag

              •      TEXT - Parser has stopped parsing to report text between tags.

              •      END_DOKUMENT - Parser has finished parsing without error.

              •      PARSE_ERROR - Parser stopped parsing at XML error in input.

       input data
              This method is only valid in state READY. It prepares the parser to use data as XML
              input to parse and switches the parser into state START_DOCUMENT.

       inputchannel channel
              This method is only valid in state READY. It prepares the parser to  read  the  XML
              input to parse out of channel and switches the parser into state START_DOCUMENT.

       inputfile filename
              This  method is only valid in state READY. It open filename and prepares the parser
              to read the XML input to parse out of that file. The method returns  TCL_ERROR,  if
              the  file  could  not  be  open in read mode. Otherwise it switches the parser into
              state START_DOCUMENT.

       next   This method is valid in state  START_DOCUMENT,  START_TAG,  END_TAG  and  TEXT.  It
              continues parsing of the XML input until the next event, which it will return.

       tag    This  method is only valid in states START_TAG and END_TAG. It returns the tag name
              of the current start or end tag.

       attributes
              This method is only valid in state START_TAG. It  returns  all  attributes  of  the
              element in a name value list.

       text   This  method  is  only  valid  in  state TEXT. It returns the character data of the
              event. There will be always at most one TEXT event between START_TAG and  the  next
              START_TAG or END_TAG event.

       skip   This method is only valid in state START_TAG. It skips to the corresponding end tag
              and ignores all events (but not XML parsing errors) on the way and returns the  new
              state END_TAG.

       find-element tagname
              This method is only valid in states START_DOCUMENT, START_TAG and END_TAG. It skips
              forward until the next element start tag with tag name tagname and returns the  new
              start  START_TAG. If there isn't such an element the parser stops at the end of the
              input and returns END_DOCUMENT.

       reset  This method is valid in all parser states. It resets the parser  into  READY  state
              and returns that.

       delete This method is valid in all parser states. It deletes the parser command.

       Miscellaneous methods:

       line   This  method  is  valid  in all parser states except READY and TEXT. It returns the
              line number of the parsing position.

       column This method is valid in all parser states except READY and  TEXT.  It  returns  the
              offset, from the beginning of the current line, of the parsing position.

KEYWORDS

       XML, pull, parsing