Revert "Try to solve the packaging issues again"

This reverts commit d37b81de4f1e64abc2f222c487785d816ab469ea.

1 files changed, 96 insertions, 0 deletions

diff --git a/astroid/transforms.py b/astroid/transforms.py
new file mode 100644
index 00000000..5d8fc91b
--- /dev/null
+++ b/astroid/transforms.py
@@ -0,0 +1,96 @@
+# copyright 2003-2015 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of astroid.
+#
+# astroid is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as published by the
+# Free Software Foundation, either version 2.1 of the License, or (at your
+# option) any later version.
+#
+# astroid is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+# for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with astroid. If not, see <http://www.gnu.org/licenses/>.
+
+import collections
+import warnings
+
+
+class TransformVisitor(object):
+    """A visitor for handling transforms.
+
+    The standard approach of using it is to call
+    :meth:`~visit` with an *astroid* module and the class
+    will take care of the rest, walking the tree and running the
+    transforms for each encountered node.
+    """
+
+    def __init__(self):
+        self.transforms = collections.defaultdict(list)
+
+    def _transform(self, node):
+        """Call matching transforms for the given node if any and return the
+        transformed node.
+        """
+        cls = node.__class__
+        if cls not in self.transforms:
+            # no transform registered for this class of node
+            return node
+
+        transforms = self.transforms[cls]
+        orig_node = node  # copy the reference
+        for transform_func, predicate in transforms:
+            if predicate is None or predicate(node):
+                ret = transform_func(node)
+                # if the transformation function returns something, it's
+                # expected to be a replacement for the node
+                if ret is not None:
+                    if node is not orig_node:
+                        # node has already be modified by some previous
+                        # transformation, warn about it
+                        warnings.warn('node %s substituted multiple times' % node)
+                    node = ret
+        return node
+
+    def _visit(self, node):
+        if hasattr(node, '_astroid_fields'):
+            for field in node._astroid_fields:
+                value = getattr(node, field)
+                visited = self._visit_generic(value)
+                setattr(node, field, visited)
+        return self._transform(node)
+
+    def _visit_generic(self, node):
+        if isinstance(node, list):
+            return [self._visit_generic(child) for child in node]
+        elif isinstance(node, tuple):
+            return tuple(self._visit_generic(child) for child in node)
+        else:
+            return self._visit(node)
+
+    def register_transform(self, node_class, transform, predicate=None):
+        """Register `transform(node)` function to be applied on the given
+        astroid's `node_class` if `predicate` is None or returns true
+        when called with the node as argument.
+
+        The transform function may return a value which is then used to
+        substitute the original node in the tree.
+        """
+        self.transforms[node_class].append((transform, predicate))
+
+    def unregister_transform(self, node_class, transform, predicate=None):
+        """Unregister the given transform."""
+        self.transforms[node_class].remove((transform, predicate))
+
+    def visit(self, module):
+        """Walk the given astroid *tree* and transform each encountered node
+
+        Only the nodes which have transforms registered will actually
+        be replaced or changed.
+        """
+        module.body = [self._visit(child) for child in module.body]
+        return self._transform(module)