Add an owner set property to QN objects. This assists extracting symbols that are affected when objects or containers are mutated in place. Also included is a utility method that simplifies constructing a QN from string.

PiperOrigin-RevId: 204303017

tensorflow/contrib/autograph/pyct/qual_names.py

@@ -30,6 +30,7 @@ import collections
 import gast
 
 from tensorflow.contrib.autograph.pyct import anno
+from tensorflow.contrib.autograph.pyct import parser
 
 
 class Symbol(collections.namedtuple('Symbol', ['name'])):
@@ -89,7 +90,8 @@ class QN(object):
       if not isinstance(base, (str, StringLiteral, NumberLiteral)):
         # TODO(mdan): Require Symbol instead of string.
         raise ValueError(
-            'For simple QNs, base must be a string or a Literal object.')
+            'for simple QNs, base must be a string or a Literal object;'
+            ' got instead "%s"' % type(base))
       assert '.' not in base and '[' not in base and ']' not in base
       self._parent = None
       self.qn = (base,)
@@ -112,6 +114,22 @@ class QN(object):
       raise ValueError('Cannot get parent of simple name "%s".' % self.qn[0])
     return self._parent
 
+  @property
+  def owner_set(self):
+    """Returns all the symbols (simple or composite) that own this QN.
+
+    In other words, if this symbol was modified, the symbols in the owner set
+    may also be affected.
+
+    Examples:
+      'a.b[c.d]' has two owners, 'a' and 'a.b'
+    """
+    owners = set()
+    if self.has_attr() or self.has_subscript():
+      owners.add(self.parent)
+      owners.update(self.parent.owner_set)
+    return owners
+
   @property
   def support_set(self):
     """Returns the set of simple symbols that this QN relies on.
@@ -122,7 +140,7 @@ class QN(object):
 
     Examples:
       'a.b' has only one support symbol, 'a'
-      'a[i]' has two roots, 'a' and 'i'
+      'a[i]' has two support symbols, 'a' and 'i'
     """
     # TODO(mdan): This might be the set of Name nodes in the AST. Track those?
     roots = set()
@@ -231,3 +249,9 @@ class QnResolver(gast.NodeTransformer):
 
 def resolve(node):
   return QnResolver().visit(node)
+
+
+def from_str(qn_str):
+  node = parser.parse_expression(qn_str)
+  node = resolve(node)
+  return anno.getanno(node, anno.Basic.QN)

tensorflow/contrib/autograph/pyct/qual_names_test.py

@@ -30,6 +30,15 @@ from tensorflow.python.platform import test
 
 class QNTest(test.TestCase):
 
+  def test_from_str(self):
+    a = QN('a')
+    b = QN('b')
+    a_dot_b = QN(a, attr='b')
+    a_sub_b = QN(a, subscript=b)
+    self.assertEqual(qual_names.from_str('a.b'), a_dot_b)
+    self.assertEqual(qual_names.from_str('a'), a)
+    self.assertEqual(qual_names.from_str('a[b]'), a_sub_b)
+
   def test_basic(self):
     a = QN('a')
     self.assertEqual(a.qn, ('a',))