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pullparser(3tcl) pullparser(3tcl) 





NAME


tdom::pullparser - Create an XML pull parser command






SYNOPSIS


package require tdom


    tdom::pullparser cmdName  ? -ignorewhitecdata ? 


    








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:



  

  
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.
    • 






  

  
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.

  

  
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.

  

  
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.

  

  
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.

  

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

  

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

  

  
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.

  

  
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.

  

  
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 state
      START_TAG. If a list of tagnames is provided with the -names
      option, any of the tagnames match. If there isn't such an element
      the parser stops at the end of the input and returns END_DOCUMENT.

  

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

  

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




Miscellaneous methods:



  

  
This method is valid in all parser states except READY and TEXT. It
      returns the line number of the parsing position. Line counting starts with
      1.

  

  
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. Column counting starts with 0.








KEYWORDS


XML, pull, parsing







  

    
    Tcl