implemented the missing Interval.__add__

Author: Richard Jones

roundup/date.py

@@ -15,7 +15,7 @@
 # BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
 # SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 # 
-# $Id: date.py,v 1.34 2002-10-10 08:24:37 richard Exp $
+# $Id: date.py,v 1.35 2002-10-11 01:25:40 richard Exp $
 
 __doc__ = """
 Date, time and time interval handling.
@@ -354,6 +354,22 @@ def __str__(self):
             l.append('%d:%02d'%(self.hour, self.minute))
         return ' '.join(l)
 
+    def __add__(self, other):
+        if isinstance(other, Date):
+            # the other is a Date - produce a Date
+            return Date(other.addInterval(self))
+        elif isinstance(other, Interval):
+            # add the other Interval to this one
+            a = self.get_tuple()
+            b = other.get_tuple()
+            if b[0] < 0:
+                i = Interval([x-y for x,y in zip(a[1:],b[1:])])
+            else:
+                i = Interval([x+y for x,y in zip(a[1:],b[1:])])
+            return i
+        # nope, no idea what to do with this other...
+        raise TypeError, "Can't add %r"%other
+
     def set(self, spec, interval_re=re.compile('''
             \s*(?P<s>[-+])?         # + or -
             \s*((?P<y>\d+\s*)y)?    # year

test/test_dates.py

@@ -15,7 +15,7 @@
 # BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
 # SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 # 
-# $Id: test_dates.py,v 1.13 2002-09-10 00:19:54 richard Exp $ 
+# $Id: test_dates.py,v 1.14 2002-10-11 01:25:40 richard Exp $ 
 
 import unittest, time
 
@@ -148,6 +148,15 @@ def testInterval(self):
         ae(str(Interval(' 14:00 ')), '+ 14:00')
         ae(str(Interval(' 0:04:33 ')), '+ 0:04:33')
 
+        # __add__
+        # XXX these are fairly arbitrary and need fixing once the __add__
+        # code handles the odd cases more correctly
+        ae(str(Interval('1y') + Interval('1y')), '+ 2y')
+        ae(str(Interval('1y') + Interval('1m')), '+ 1y 1m')
+        ae(str(Interval('1y') + Interval('2:40')), '+ 1y 2:40')
+        ae(str(Interval('1y') + Interval('- 1y')), '+')
+        ae(str(Interval('1y') + Interval('- 1m')), '+ 1y -1m')
+
 def suite():
    return unittest.makeSuite(DateTestCase, 'test')