From 04cc61d317213ad3a1964e3420777a2e82fe2ee2 Mon Sep 17 00:00:00 2001
From: LtWorf <LtWorf@014f5005-505e-4b48-8d0a-63407b615a7c>
Date: Mon, 11 May 2009 16:38:49 +0000
Subject: [PATCH] redoundant renames still under work... this thing is harder
 than i though

git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@156 014f5005-505e-4b48-8d0a-63407b615a7c
---
 relational/optimizations.py | 40 ++++++++++++++++++++++++-------------
 relational/optimizer.py     |  7 +++++--
 2 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/relational/optimizations.py b/relational/optimizations.py
index 157c98c..1737ce1 100644
--- a/relational/optimizations.py
+++ b/relational/optimizations.py
@@ -121,22 +121,34 @@ def selection_inside_projection(n):
 def subsequent_renames(n):
     '''This function removes redoundant subsequent renames'''
     changes=0
-    print "in"
-    if n.name=='π' and n.child.name==n.name:
-        changes=1
-        print "in-in"
-        
-        n.prop+=','+n.child.prop
-
-        _vars={}
-        for i in n.child.prop.split(','):
-            q=i.split('➡')
-            c_vars[q[0]]=q[1]
-        n.child=n.child.child
-        
     
+    if n.name=='ρ' and n.child.name==n.name:
+        changes=1
+        
+        
+        print "PROP",n.prop,"==========",n.child.prop
+        n.prop+=','+n.child.prop
+        
+        _vars={}
+        for i in n.prop.split(','):
+            q=i.split('➡')
+            _vars[q[0]]=q[1]
+        n.child=n.child.child
+        print _vars
+        for i in list(_vars.keys()):
+            print i
+            if _vars[i] in _vars.keys():
+                #Double rename on attribute
+                print "i:%s\tvars[i]:%s\t_vars[_vars[i]]: %s\n" % (i,_vars[i],_vars[_vars[i]])
+                _vars[i] =  _vars[_vars[i]]
+                _vars.pop(i)
+        n.prop=""
+        print _vars
+        for i in _vars.items():
+            n.prop+="%s➡%s" % (i[0],i[1])
+            
     #recoursive scan
-    if n.kind==optimizer.UNARY:
+    if n.kind==optimizer.UNARY:        
         changes+=subsequent_renames(n.child)
     elif n.kind==optimizer.BINARY:
         changes+=subsequent_renames(n.right)
diff --git a/relational/optimizer.py b/relational/optimizer.py
index bb16f70..7d8d590 100644
--- a/relational/optimizer.py
+++ b/relational/optimizer.py
@@ -192,8 +192,11 @@ if __name__=="__main__":
     #a= tokenize("(a - (a ᑌ b) * π a,b (a-b)) - ρ 123 (a)")
     #a= tokenize(u"π a,b (a*b)")
     #a=tokenize("(a-b*c)*(b-c)")
-    print tree("σ i==2 (c ᑌ d - (aᑎb))") == tree("σ i==3 (c ᑌ d - (aᑎb))")
-    a=general_optimize("π age➡a(π ciccio➡age(R))")
+    #print tree("σ i==2 (c ᑌ d - (aᑎb))") == tree("σ i==3 (c ᑌ d - (aᑎb))")
+    print tree("ρ age➡a,cognome➡cogn(ρ ciccio➡age,nome➡nom(R))")
+    
+    
+    a=general_optimize("ρ age➡a(ρ ciccio➡age(R))")
     #a=general_optimize("σ i==2 (σ b>5 (d))")
     print '=========',a
     #print node(a)