diff -r db478d17bc3a -r 8dc4ebc97777 plcopen/XSLTModelQuery.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plcopen/XSLTModelQuery.py	Fri Feb 16 18:24:55 2018 +0100
@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# This file is part of Beremiz.
+# See COPYING file for copyrights details.
+
+from __future__ import absolute_import
+import os
+from lxml import etree
+import util.paths as paths
+from plcopen.structures import StdBlckLibs
+
+ScriptDirectory = paths.AbsDir(__file__)
+
+class XSLTModelQuery(object):
+    """ a class to handle XSLT queries on project and libs """
+    def __init__(self, controller, xsltpath, ext = []):
+        # arbitrary set debug to false, updated later
+        self.debug = False
+
+        # merge xslt extensions for library access to query specific ones
+        xsltext = [
+            ("GetProject", lambda *_ignored: 
+                controller.GetProject(self.debug)),
+            ("GetStdLibs", lambda *_ignored: 
+                [lib for lib in StdBlckLibs.values()]),
+            ("GetExtensions", lambda *_ignored: 
+                [ctn["types"] for ctn in controller.ConfNodeTypes])
+        ] + ext
+
+        # parse and compile. "beremiz" arbitrary namespace for extensions 
+        self.xslt = etree.XSLT(
+            etree.parse(
+                os.path.join(ScriptDirectory, xsltpath),
+                etree.XMLParser()),
+            extensions={ ("beremiz", name):call for name, call in xsltext})
+
+    def _process_xslt(self, root, debug, **kwargs):
+        self.debug = debug
+        return self.xslt(root,**{k:etree.XSLT.strparam(v) for k,v in kwargs.iteritems()})