Asn1Item.hasValue() added to easily distinguish initalized ASN.1 objects

from uninitialized ones (e.g. pure pyasn1 types)

2 files changed, 8 insertions, 3 deletions

diff --git a/CHANGES b/CHANGES
index c6ecfc6..1ccd415 100644
--- a/CHANGES
+++ b/CHANGES
@@ -50,6 +50,8 @@ Revision 0.1.8rc3
 - Float typed mantissa initializer to REAL type for base 2 added.
 - Encoding bases 8 and 16 support for REAL type binary encoder added.
 - More strict CER/DER encoders added for GeneralizedTime and UTCTime types.
+- Asn1Item.hasValue() added to easily distinguish initalized ASN.1 objects
+  from uninitialized ones (e.g. pure types).
 - Fix to REAL type binary decoder to handle different bases and scale factor.
 - Fix to TagSet.repr() to include [obsolete] baseTag information.
 - Fix to broken REAL type decoding handling.
diff --git a/pyasn1/type/base.py b/pyasn1/type/base.py
index 600ae98..155ed74 100644
--- a/pyasn1/type/base.py
+++ b/pyasn1/type/base.py
@@ -101,6 +101,9 @@ class AbstractSimpleAsn1Item(Asn1ItemBase):
         def __bool__(self): return bool(self._value)
     def __hash__(self): return self.__hashedValue
 
+    def hasValue(self):
+        return not isinstance(self._value, NoValue)
+
     def clone(self, value=None, tagSet=None, subtypeSpec=None):
         if value is None and tagSet is None and subtypeSpec is None:
             return self
@@ -132,10 +135,10 @@ class AbstractSimpleAsn1Item(Asn1ItemBase):
     def prettyOut(self, value): return str(value)
 
     def prettyPrint(self, scope=0):
-        if self._value is noValue:
-            return '<no value>'
-        else:
+        if self.hasValue():
             return self.prettyOut(self._value)
+        else:
+            return '<no value>'
 
     # XXX Compatibility stub
     def prettyPrinter(self, scope=0): return self.prettyPrint(scope)