DOKK / manpages / debian 12 / tdom / tnc.3tcl.en
tnc(3tcl) tnc(3tcl) 







tnc - tnc is an expat parser object extension, that validates the
    XML stream against the document DTD while parsing.








package require tdom
package require tnc
set parser [expat]
tnc $parser enable










tnc adds the C handler set "tnc" to a tcl expat
    parser obj. This handler set is a simple DTD validator. If the validator
    detects a validation error, it sets the interp result, signals error and
    stops parsing. There isn't any validation error recovering. As a
    consequence, only valid documents are completely parsed.


This handler set has only three methods:



  

  






Adds the tnc C handler set to a Tcl expat parser object.





  

  






Removes the tnc validatore from the parser parserObj and
    frees all information, stored by it.





  

  






Returns a new created validation command, if one is available from
    the parser command, otherwise it signals error. The name of the validation
    command is the validateCmdName, if this optional argument was given,
    or a random chosen name. A validation command is available in a parser
    command, if the parser with tnc enabled was previously used, to parse an XML
    document with a valid doctype declaration, a valid external subset, if one
    was given by the doctype declaration, and a valid internal subset. The
    further document doesn't need to be valid, to make the validation command
    available. The validation command can only get received one time from the
    parser command. The created validation command has this syntax:










validationCmd method ?args?




The valid methods are:



  

  
Checks, if the given domDocument is valid against the DTD information
      represented by the validation command. Returns 1, if the document ist
      valid, 0 otherwise. If the varName argument is given, then the
      variable it names is set to the detected reason for the validation error
      or to the empty string in case of a valid document.

  

  
Checks, if the given subtree with domNode as root element is a
      possible valid subtree of a document conforming to the DTD information
      represented by the validation command. IDREF could not checked, while
      validating only a subtree, but it is checked, that every known ID
      attribute in the subtree is unique. Returns 1, if the subtree is OK, 0
      otherwise. If the varName argument is given, then the variable it
      names is set to the detected reason for the validation error or to the
      empty string in case of a valid subtree.

  

  
Checks, if there is an element declaration for the name of the
      elementNode in the DTD represented by the validation command and,
      if yes, if the attributes of the elementNode are conform to the
      ATTLIST declarations for that element in the DTD. Returns 1, if the
      attributes and there value types are OK, 0 otherwise. If the
      varName argument is given, then the variable it names is set to the
      detected reason for the validation error or to the empty string in case
      the element has all its required attributes, only declared attributes and
      the values of the attributes matches there type.

  

  
Deletes the validation command and frees the memory used by it. Returns
      the empty string.












The validation error reports could be much more informative and
    user-friendly.


The validator doesn't detect ambiguous content models (see XML
    recomendation Section 3.2.1 and Appendix E). Most Java validators also
    doesn't, but handle such content models right anyhow. Tnc does not; if your
    DTD has such ambiguous content models, tnc can not used to validate
    documents against such (not completely XML spec compliant) DTDs.


It isn't possible to validate XML documents with
    standalone="yes" in the XML Declaration


Violations of the validity constraints Proper Group/PE Nesting and
    Proper Conditional Section/PE Nesting are not detected. They could only
    happen inside a invalid DTD, not in the content of a document.








Validation, DTD







  

    
    Tcl