genClassesH

#!/usr/bin/env python

from optparse import OptionParser
from xml.sax import parseString
from xml.sax.handler import ContentHandler
from sys import exit

def die(msg):
  print msg
  exit(1)
 
class ClassesDefContentHandler(ContentHandler):
  def __init__(self):
    self.classes = []
    self.headers = []
  
  def startElement(self, name, attrs):
    # <*> is used to indicate "whatever specified in classes.h" which obviously
    # in this case does not work anymore, because we want to generate such a
    # file. Therefore we exit with an error.
    #
    # If a class has argument "concrete", classes_def.xml declaration is enough
    # to generate the dictionary and we do not need to create an instance in
    # classes.h.
    if name == "class":
      if "pattern" in attrs:
        die("Cannot use pattern '%s': please declare actual class names to use automatic classes.h generation." % attrs["pattern"])
      if "type" in attrs and attrs["type"] == "concrete":
        return
      self.classes.append(attrs["name"])
    if name == "include":
      if "file" in attrs:
        self.headers.append("\"" + attrs["file"] + "\"")
      elif "system" in attrs:
        self.headers.append("<"+attrs["system"] + ">")
      else:
        die("Malformed classes_def.xml")

  def endDocument(self):
    print "\n".join("#include %s" % x for x in self.headers)
    if self.headers: print ""
    print "namespace {\n  struct dictionary {"
    print "\n".join("    %s a%s;" % (n, i) for (i,n) in enumerate(self.classes))
    print "};\n}"

if __name__ == "__main__":
  parser = OptionParser(usage="%{progname}s <classes_def.xml>")
  opts, args = parser.parse_args()
  if not args:
    parser.error("Please specify the input <classes_def.xml>")
  if len(args) > 1:
    parser.error("Too many input files specified")

  # Replace any occurence of <>& in the attribute values by the xml parameter
  rxml, nxml = file(args[0]).read(), ''
  q1,q2 = 0,0
  for c in rxml :
    if   (q1 or q2) and c == '<' : nxml += '&lt;'
    elif (q1 or q2) and c == '>' : nxml += '&gt;'
    # elif (q1 or q2) and c == '&' : nxml += '&amp;'
    else                         : nxml += c
    if c == '"' : q1 = not q1
    if c == "'" : q2 = not q2

  parseString(nxml, ClassesDefContentHandler())