--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pyams_utils/tales.py Wed Dec 05 12:45:56 2018 +0100
@@ -0,0 +1,116 @@
+#
+# Copyright (c) 2008-2015 Thierry Florac <tflorac AT ulthar.net>
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+
+__docformat__ = 'restructuredtext'
+
+
+# import standard library
+import re
+
+# import interfaces
+from pyams_utils.interfaces.tales import ITALESExtension
+
+# import packages
+from chameleon.astutil import Symbol
+from chameleon.codegen import template
+from chameleon.tales import StringExpr
+from zope.contentprovider.tales import addTALNamespaceData
+
+
+class ContextExprMixin(object):
+ """Mixin-class for expression compilers"""
+
+ transform = None
+
+ def __call__(self, target, engine):
+ # Make call to superclass to assign value to target
+ assignment = super(ContextExprMixin, self).__call__(target, engine)
+ transform = template("target = transform(econtext, target)",
+ target=target,
+ transform=self.transform)
+ return assignment + transform
+
+
+FUNCTION_EXPRESSION = re.compile('(.+)\((.+)\)', re.MULTILINE | re.DOTALL)
+ARGUMENTS_EXPRESSION = re.compile('[^(,)]+')
+
+
+def render_extension(econtext, name):
+ """TALES extension renderer
+
+ See :ref:`tales` for complete description.
+ """
+
+ def get_value(econtext, arg):
+ """Extract argument value from context
+
+ Extension expression language is quite simple. Values can be given as
+ positioned strings, integers or named arguments of the same types.
+ """
+ arg = arg.strip()
+ if arg.startswith('"') or arg.startswith("'"):
+ # may be a quoted string...
+ return arg[1:-1]
+ if '=' in arg:
+ key, value = arg.split('=', 1)
+ value = get_value(econtext, value)
+ return {key.strip(): value}
+ try:
+ arg = int(arg) # check integer value
+ except ValueError:
+ args = arg.split('.')
+ result = econtext.get(args.pop(0))
+ for arg in args:
+ result = getattr(result, arg)
+ return result
+ else:
+ return arg
+
+ name = name.strip()
+ context = econtext.get('context')
+ request = econtext.get('request')
+ view = econtext.get('view')
+
+ args, kwargs = [], {}
+ func_match = FUNCTION_EXPRESSION.match(name)
+ if func_match:
+ name, arguments = func_match.groups()
+ for arg in map(lambda x: get_value(econtext, x), ARGUMENTS_EXPRESSION.findall(arguments)):
+ if isinstance(arg, dict):
+ kwargs.update(arg)
+ else:
+ args.append(arg)
+
+ registry = request.registry
+ extension = registry.queryMultiAdapter((context, request, view), ITALESExtension, name=name)
+ if extension is None:
+ extension = registry.queryMultiAdapter((context, request), ITALESExtension, name=name)
+ if extension is None:
+ extension = registry.queryAdapter(context, ITALESExtension, name=name)
+
+ # provide a useful error message, if the extension was not found.
+ if extension is None:
+ return None
+
+ # Insert the data gotten from the context
+ addTALNamespaceData(extension, econtext)
+
+ return extension.render(*args, **kwargs)
+
+
+class ExtensionExpr(ContextExprMixin, StringExpr):
+ """tales: TALES expression
+
+ This expression can be used to call a custom named adapter providing ITALESExtension interface.
+ """
+
+ transform = Symbol(render_extension)