From 19ac2aaacdf0a31cfa59e585286c8624252afd2f Mon Sep 17 00:00:00 2001
From: LtWorf <LtWorf@014f5005-505e-4b48-8d0a-63407b615a7c>
Date: Fri, 26 Nov 2010 09:12:34 +0000
Subject: [PATCH] - Set hash method for the classes

git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@265 014f5005-505e-4b48-8d0a-63407b615a7c
---
 CHANGELOG              | 1 +
 relational/parser.py   | 2 ++
 relational/relation.py | 7 ++++++-
 relational/rtypes.py   | 4 +++-
 4 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 282419f..92f9c47 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -10,6 +10,7 @@
 - Fixed optimization involving selection and parenthesis in the expression (Rev 260)
 - Fixed futile_union_intersection_subtraction optimization that didn't work when selection operator was in the left subtree (Rev 261)
 - Module parallel does something, can execute queries in parallel
+- Set hash method for the classes
 
 0.11
 - Font is set only on windows (Rev 206)
diff --git a/relational/parser.py b/relational/parser.py
index 04319a1..cc3c184 100644
--- a/relational/parser.py
+++ b/relational/parser.py
@@ -51,6 +51,7 @@ class node (object):
     
     This class is used to convert an expression into python code.'''
     kind=None
+    __hash__=None
     
     def __init__(self,expression=None):
         '''Generates the tree from the tokenized expression
@@ -186,6 +187,7 @@ class node (object):
         if self.kind==BINARY:
             return self.left==other.left and self.right==other.right
         return True
+        
     def __str__(self):
         if (self.kind==RELATION):
             return self.name
diff --git a/relational/relation.py b/relational/relation.py
index 230fdfc..6475fd2 100644
--- a/relational/relation.py
+++ b/relational/relation.py
@@ -25,6 +25,8 @@ class relation (object):
     A relation can be represented using a table
     Calling an operation and providing a non relation parameter when it is expected will
     result in a None value'''    
+    __hash__=None
+    
     def __init__(self,filename=""):
         '''Creates a relation, accepts a filename and then it will load the relation from
         that file. If no parameter is supplied an empty relation is created. Empty
@@ -185,7 +187,6 @@ class relation (object):
             if (newt.header.rename(old,new)) == False:
                 return None
         
-        #TODO only copy the link and mark the new relation as read only
         newt.content=self.content
         newt._readonly=True
         return newt
@@ -511,9 +512,13 @@ class header (object):
     '''This class defines the header of a relation.
     It is used within relations to know if requested operations are accepted'''
     
+    #Since relations are mutalbe we explicitly block hashing them
+    __hash__=None
+    
     def __init__(self,attributes):
         '''Accepts a list with attributes' names. Names MUST be unique'''
         self.attributes=attributes
+        
     def __repr__(self):
         return "header(%s)" % (self.attributes.__repr__())
         
diff --git a/relational/rtypes.py b/relational/rtypes.py
index 8727251..0f38bf4 100644
--- a/relational/rtypes.py
+++ b/relational/rtypes.py
@@ -53,7 +53,9 @@ class rdate (object):
         self.month=self.intdate.month
         self.weekday=self.intdate.weekday()
         self.year=self.intdate.year
-        
+    
+    def __hash__(self):
+        return self.intdate.__hash__()
     def __str__(self):
         return self.intdate.__str__()
     def __add__(self,days):