* Module wpylib.py.introspection: Tools for aiding introspection in python.

* Added function: name_rlookup().
  Imported from Cr2 analysis script, original name was: search_var_name.
  No edit has been made yet.

py/introspection.py

@@ -0,0 +1,57 @@
+# -*- python -*-
+#
+# wpylib.py.introspection
+# Created: 20150819
+# Wirawan Purwanto
+#
+# Advanced introspection tools for python
+#
+
+def name_rlookup(val, namespace, prefix=None, rx_match=None, lookup="dict"):
+  """Reverse lookup of variable/object name.
+
+  Yields the list of object names in the namespace whose respective values are
+  equal to `val`.
+
+  This is useful for example to reverse-lookup an object's name, but only in
+  restricted contexts (e.g. when the value to look for is unique).
+  """
+  # Imported 20150819
+  # Original subroutine name: search_var_name (from Cr2_analysis_cbs.py).
+  if lookup == "dict":
+    names = namespace.keys()
+  else:
+    # attribute lookup
+    names = dir(namespace)
+  if prefix != None:
+    names_filt = [ n for n in names if n.startswith(prefix) ]
+  elif rx_match != None:
+    # TODO later: for my regexp object?
+    if True:
+      if isinstance(rx_match, basestring):
+        names_filt = [ n for n in names if re.search(rx_match, n) ]
+      else:
+        # assume a re.RegexObject-like object:
+        names_filt = [ n for n in names if rx_match.search(n) ]
+  else:
+    names_filt = names
+  names_match = []
+  type_val = type(val)
+  if lookup == "dict":
+    for n in names_filt:
+      try:
+        v = namespace[n]
+      except:
+        continue
+      if type(v) == type_val and v == val:
+        names_match.append(n)
+  else:
+    for n in names_filt:
+      try:
+        v = getattr(namespace, n)
+      except:
+        continue
+      if type(v) == type_val and v == val:
+        names_match.append(n)
+  return names_match
+