add support to initialise NTEnum like NTScalar

src/p4p/nt/enum.py

@@ -38,6 +38,8 @@ def __repr__(self):
 class NTEnum(NTBase):
     """Describes a string selected from among a list of possible choices.  Stored internally as an integer
     """
+    Value = Value
+
     @staticmethod
     def buildType(extra=[], display=False, control=False, valueAlarm=False):
         F = [
@@ -61,19 +63,35 @@ def __init__(self, **kws):
 
     def wrap(self, value, choices=None, **kws):
         """Pack python value into Value
+
+        Accepts dict to explicitly initialize fields by name.
+        Any other type is assigned to the 'value' field via
+        the self.assign() method.
         """
-        V = self.type()
-        if choices is not None:
-            V['value.choices'] = choices
-
-        if isinstance(value, dict):
-            # assume dict of index and choices list
-            V.value = value
-            self._choices = V['value.choices']
+        if isinstance(value, Value):
+            pass
+        elif isinstance(value, ntwrappercommon):
+            kws.setdefault('timestamp', value.timestamp)
+            value = value.raw
+        elif isinstance(value, dict):
+            # if index, choices not in value.keys(), then
+            # use value dict to initalize fields by name
+            if {'index', 'choices'}.isdisjoint(value):
+                value = self.Value(self.type, value)
+            # if value = {'index': ..., 'choices': ...}, then
+            # assign these to value.index, value.choices
+            else:
+                value = self.Value(self.type, {'value': value})
         else:
             # index or string
+            V = self.type()
+            if choices is not None:
+                V['value.choices'] = choices
             self.assign(V, value)
-        return self._annotate(V, **kws)
+            value = V
+
+        self._choices = value['value.choices'] or self._choices
+        return self._annotate(value, **kws)
 
     def unwrap(self, value):
         """Unpack a Value into an augmented python type (selected from the 'value' field)

src/p4p/test/test_nt.py

@@ -267,18 +267,41 @@ def testSubStore(self):
         self.assertEqual(V.a.value.index, 1)
         self.assertEqual(V.b.value.index, 0)
 
-    def testWrap(self):
+    def testDictionaryOfValueWrap(self):
         W = nt.NTEnum()
         V = W.wrap({'index':1, 'choices':['X','Y']})
 
         self.assertEqual(V.value.index, 1)
         self.assertEqual(V.value.choices, ['X','Y'])
 
+    def testDictionaryWrap(self):
+        W = nt.NTEnum()
+        V = W.wrap({'value.index': 0,
+                    'value.choices': ['X','Y'],
+                    'alarm.severity': 1})
+
+        self.assertEqual(V.value.index, 0)
+        self.assertEqual(V.value.choices, ['X','Y'])
+        self.assertEqual(V.alarm.severity, 1)
+
+    def testWrap(self):
         W = nt.NTEnum()
         V = W.wrap(0)
 
         self.assertEqual(V.value.index, 0)
         self.assertEqual(V.value.choices, [])
+        self.assertTrue(V.changed('value'))
+
+        V = W.wrap(1, choices=['X', 'Y'])
+
+        self.assertEqual(V.value.index, 1)
+        self.assertEqual(V.value.choices, ['X', 'Y'])
+        self.assertTrue(V.changed('value'))
+
+        V = W.wrap('X')
+
+        self.assertEqual(V.value.index, 0)
+        self.assertTrue(V.changed('value.index'))
 
     def testAssign(self):
         W = nt.NTEnum()