Issue 1780: Allow leading and trailing whitespace in Decimal constructor,
when constructing from a string. Disallow trailing newlines in
Context.create_decimal.
diff --git a/Lib/decimal.py b/Lib/decimal.py
index 8b54821..7e24516 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -523,6 +523,8 @@
         Decimal("314")
         >>> Decimal(Decimal(314))        # another decimal instance
         Decimal("314")
+        >>> Decimal('  3.14  \\n')        # leading and trailing whitespace okay
+        Decimal("3.14")
         """
 
         # Note that the coefficient, self._int, is actually stored as
@@ -538,7 +540,7 @@
         # From a string
         # REs insist on real strings, so we can too.
         if isinstance(value, basestring):
-            m = _parser(value)
+            m = _parser(value.strip())
             if m is None:
                 if context is None:
                     context = getcontext()
@@ -3533,7 +3535,16 @@
         return rounding
 
     def create_decimal(self, num='0'):
-        """Creates a new Decimal instance but using self as context."""
+        """Creates a new Decimal instance but using self as context.
+
+        This method implements the to-number operation of the
+        IBM Decimal specification."""
+
+        if isinstance(num, basestring) and num != num.strip():
+            return self._raise_error(ConversionSyntax,
+                                     "no trailing or leading whitespace is "
+                                     "permitted.")
+
         d = Decimal(num, context=self)
         if d._isnan() and len(d._int) > self.prec - self._clamp:
             return self._raise_error(ConversionSyntax,
@@ -5148,7 +5159,7 @@
         (?P<diag>\d*)         # with (possibly empty) diagnostic information.
     )
 #    \s*
-    $
+    \Z
 """, re.VERBOSE | re.IGNORECASE).match
 
 _all_zeros = re.compile('0*$').match
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
index 03cff60..2135637 100644
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -429,6 +429,10 @@
         #just not a number
         self.assertEqual(str(Decimal('ugly')), 'NaN')
 
+        #leading and trailing whitespace permitted
+        self.assertEqual(str(Decimal('1.3E4 \n')), '1.3E+4')
+        self.assertEqual(str(Decimal('  -7.89')), '-7.89')
+
     def test_explicit_from_tuples(self):
 
         #zero
@@ -517,6 +521,10 @@
         self.assertEqual(str(d), '456789')
         d = nc.create_decimal('456789')
         self.assertEqual(str(d), '4.57E+5')
+        # leading and trailing whitespace should result in a NaN;
+        # spaces are already checked in Cowlishaw's test-suite, so
+        # here we just check that a trailing newline results in a NaN
+        self.assertEqual(str(nc.create_decimal('3.14\n')), 'NaN')
 
         # from tuples
         d = Decimal( (1, (4, 3, 4, 9, 1, 3, 5, 3, 4), -25) )