text: #!/usr/bin/python
  
  """
  A command-line interface to the validating xmlproc parser. Prints error
  messages and can output the parsed data in various formats.
  """
  
  usage=\
  """
  Usage:
  
    xvcmd.py [options] [urlstodocs]
  
    ---Options:  
    -c catalog:   path to catalog file to use to resolve public identifiers
    -l language:  ISO 3166 language code for language to use in error messages
    -o format:    Format to output parsed XML. 'e': ESIS, 'x': canonical XML
                  and 'n': normalized XML. No data will be output if this
                  option is not specified.
    urlstodocs:   URLs to the documents to parse. (You can use plain file names
                  as well.) Can be omitted if a catalog is specified and contains
                  a DOCUMENT entry.
    -n:           Report qualified names as 'URI name'. (Namespace processing.)
    --nowarn:     Suppress warnings.
    --entstck:    Show entity stack on errors.
    --rawxml:     Show raw XML string where error occurred.
              
    Catalog files with URLs that end in '.xml' are assumed to be XCatalogs,
    all others are assumed to be SGML Open Catalogs.
  
    If the -c option is not specified the environment variables XMLXCATALOG
    and XMLSOCATALOG will be used (in that order).
  """
  
  from xml.parsers.xmlproc import xmlval,catalog,xcatalog,xmlproc
  import outputters
  import sys, getopt, os, string
  
  # --- Utilities
  
  def print_usage(message):
      print message
      print usage
      sys.exit(1)
  
  # --- Initialization
  
  print "xmlproc version %s" % xmlval.version
  
  p=xmlval.XMLValidator()
  
  # --- Interpreting options
  
  try:
      (options,sysids)=getopt.getopt(sys.argv[1:],"c:l:o:n",
                                     ["nowarn","entstck","rawxml"])
  except getopt.error,e:
      print_usage("Usage error: "+e)
      
  warnings=1
  entstack=0
  rawxml=0
  cat=None
  pf=None
  namespaces=0
  app=xmlproc.Application()
  err_lang=None
  
  for option in options:
      if option[0]=="-c":
          cat=option[1]
      elif option[0]=="-l":
          try:
              p.set_error_language(option[1])
              err_lang=option[1]
          except KeyError:
              print "Error: Language '%s' not available" % option[1]
      elif option[0]=="-o":
          if string.lower(option[1]) == "e":
              app = outputters.ESISDocHandler()            
          elif string.lower(option[1]) == "x":
              app = outputters.Canonizer()
          elif string.lower(option[1]) == "n":
              app = outputters.DocGenerator()
          else:
              print_usage("Error: Unknown output format " + option[1])
              
      elif option[0]=="-n":
          namespaces=1
      elif option[0]=="--nowarn":
          warnings=0
      elif option[0]=="--entstck":
          entstack=1
      elif option[0]=="--rawxml":
          rawxml=1
  
  # Acting on option settings
  
  err = outputters.MyErrorHandler(p, p.parser, warnings, entstack, rawxml)
  p.set_error_handler(err)
  
  if namespaces:
      from xml.parsers.xmlproc import namespace
  
      nsf=namespace.NamespaceFilter(p)
      nsf.set_application(app)
      p.set_application(nsf)
  else:
      p.set_application(app)
  
  if cat!=None:
      pf=xcatalog.FancyParserFactory(err_lang)
  elif cat==None and os.environ.has_key("XMLXCATALOG"):
      cat=os.environ["XMLXCATALOG"]
      pf=xcatalog.XCatParserFactory(err_lang)
  elif cat==None and os.environ.has_key("XMLSOCATALOG"):
      cat=os.environ["XMLSOCATALOG"]
      pf=catalog.CatParserFactory(err_lang)
  
  if cat!=None:
      print "Parsing catalog file '%s'" % cat
      cat=catalog.xmlproc_catalog(cat,pf,err)
      p.set_pubid_resolver(cat)
  
  if len(sysids)==0:
      if cat==None:
          print_usage("You must specify a system identifier if no catalog is "
                      "used")
      elif cat.get_document_sysid()==None:
          print_usage("You must specify a system identifier if the catalog has "
                      "no DOCUMENT entry")
  
      sysids=[cat.get_document_sysid()]
      print "Parsing DOCUMENT '%s' from catalog" % sysids[0]
  
  # --- Parsing
  
  for sysid in sysids:
      print
      print "Parsing '%s'" % sysid
      p.parse_resource(sysid)
      print
      print "Parse complete, %d error(s)" % err.errors,
      if warnings:
          print "and %d warning(s)" % err.warnings
      else:
          print
      err.reset()
      p.reset()
  