- Fixes __eq__ method

- Fixes tokenization of python expressions, using python's builtin module tokenizer


git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@256 014f5005-505e-4b48-8d0a-63407b615a7c

relational/optimizations.py

@@ -32,6 +32,10 @@ A function will have to return the number of changes performed on the tree.
 
 import optimizer
 import parser
+
+from cStringIO import StringIO
+from tokenize import generate_tokens
+
 sel_op=('//=','**=','and','not','in','//','**','<<','>>','==','!=','>=','<=','+=','-=','*=','/=','%=','or','+','-','*','/','&','|','^','~','<','>','%','=','(',')',',','[',']')
 
 def replace_node(replace,replacement):
@@ -307,58 +311,22 @@ def tokenize_select(expression):
     selection. The expression can contain parenthesis.
     It will use a subclass of str with the attribute level, which
     will specify the nesting level of the token into parenthesis.'''
-    sel_op=('//=','**=','and ','not ','in ','//','**','<<','>>','==','!=','>=','<=','+=','-=','*=','/=','%=','or ','+','-','*','/','&','|','^','~','<','>','%','=','(',')',',','[',']')
+    g=generate_tokens(StringIO(expression).readline)
-    l=0
+    l=list(token[1] for token in g)
-    while l!=len(expression):
-        l=len(expression)
-        if expression.startswith('(') and parser.find_matching_parenthesis(expression)+1==len(expression):
-            expression= expression[1:-1]
     
-    tokens=[]
+    l.remove('')
-    temp=''
-    level=0
     
-    while len(expression)!=0:
+    #Changes the 'a','.','method' token group into a single 'a.method' token
-        expression=expression.strip()
+    try:
+        while True:
+            dot=l.index('.')
+            l[dot]='%s.%s' % (l[dot-1],l[dot+1])
+            l.pop(dot+1)
+            l.pop(dot-1)
+    except:
+        pass
     
-        if expression[0:1]=='(': #Expression into parenthesis
+    return l
-            level+=1
-        elif expression[0:1]==')':
-            level-=1
-        
-        for i in range(4,0,-1):#operators
-            if expression[0:i] in sel_op:
-                t=level_string(temp)
-                t.level=level
-                tokens.append(t)
-                temp=''
-                t=level_string(expression[0:i].strip())
-                t.level=level
-                tokens.append(t)
-                expression=expression[i:]
-        if expression[0:1]=="'":#String
-            end=expression.index("'",1)
-            while expression[end-1]=='\\':
-                end=expression.index("'",end+1)
-            #Add string to list
-            t=level_string(expression[0:end+1])
-            t.level=level
-            tokens.append(t)
-            expression=expression[end+1:]
-        else:
-            temp+=expression[0:1]
-            expression=expression[1:]
-            pass
-    if len(temp)!=0:
-        t=level_string(temp)
-        t.level=level
-        tokens.append(t)
-    while True:
-        try:
-            tokens.remove('')
-        except:
-            break
-    return tokens
 
 def swap_rename_projection(n):
     '''This function locates things like π k(ρ j(R))

relational/optimizer.py

@@ -54,7 +54,6 @@ def optimize_all(expression,rels):
             total+=i(n) #Performs the optimization
     return n.__str__()
 
-
 def specific_optimize(expression,rels):
     '''This function performs specific optimizations. Means that it will need to
     know the fields used by the relations

relational/relation.py

@@ -381,13 +381,15 @@ class relation (object):
     def __eq__(self,other):
         '''Returns true if the relations are the same, ignoring order of items.
         This operation is rather heavy, since it requires sorting and comparing.'''
+        other=self._rearrange_(other) #Rearranges attributes' order so can compare tuples directly
+        
         if (self.__class__!=other.__class__)or(self.header!=other.header):
             return False #Both parameters must be a relation
 
         if set(self.header.attributes)!=set(other.header.attributes):
             return False
         
-        other=self._rearrange_(other) #Rearranges attributes' order so can compare tuples directly
+        
         
         #comparing content
         return self.content==other.content
@@ -519,20 +521,18 @@ class header (object):
     def rename(self,old,new):
         '''Renames a field. Doesn't check if it is a duplicate.
         Returns True if the field was renamed, False otherwise'''
-        for i in range(len(self.attributes)):
+        print self.attributes,old, new
-            if self.attributes[i]==old:
-                self.attributes[i]=new
-                return True
-        return False #Requested field was not found    
         
+        try:
+            id_=self.attributes.index(old)
+            self.attributes[id_]=new
+        except:
+            return False
+        return True
     
     def sharedAttributes(self,other):
         '''Returns how many attributes this header has in common with a given one'''
-        res=0
+        return len(set(self.attributes).intersection(set(other.attributes)))
-        for i in self.attributes:
-            if i in other.attributes:
-                res+=1
-        return res
     
     def __str__(self):
         '''Returns String representation of the field's list'''