change parser: now left hand side var of let clause will not enter symbol table scope until right hand side expression is parsed.

git-svn-id: https://asterixdb.googlecode.com/svn/branches/asterix_function_merge@483 eaa15691-b419-025a-1212-ee371bd00084
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/translator/AqlExpressionToPlanTranslator.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/translator/AqlExpressionToPlanTranslator.java
index e004a7d..8f928f2 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/translator/AqlExpressionToPlanTranslator.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/translator/AqlExpressionToPlanTranslator.java
@@ -348,9 +348,9 @@
                 break;
             }
             default: {
+            	v = context.newVar(lc.getVarExpr());
                 Pair<ILogicalExpression, Mutable<ILogicalOperator>> eo = aqlExprToAlgExpression(lc.getBindingExpr(),
-                        tupSource);
-                v = context.newVar(lc.getVarExpr());
+                        tupSource);                
                 returnedOp = new AssignOperator(v, new MutableObject<ILogicalExpression>(eo.first));
                 returnedOp.getInputs().add(eo.second);
                 break;
diff --git a/asterix-algebra/src/main/javacc/AQLPlus.jj b/asterix-algebra/src/main/javacc/AQLPlus.jj
index 4a10ca0..3422652 100644
--- a/asterix-algebra/src/main/javacc/AQLPlus.jj
+++ b/asterix-algebra/src/main/javacc/AQLPlus.jj
@@ -1237,12 +1237,9 @@
 	extendCurrentScope();
 }
 {
-    "let" varExp = Variable()
+    "let" varExp = Variable() ":=" beExp = Expression()
     {
       getCurrentScope().addNewVarSymbolToScope(varExp.getVar());
-	}
-     ":=" beExp = Expression()
-    {
       lc.setVarExpr(varExp);
       lc.setBeExpr(beExp);
       return lc;
diff --git a/asterix-aql/src/main/javacc/AQL.jj b/asterix-aql/src/main/javacc/AQL.jj
index b55f9c8..0767c4e 100644
--- a/asterix-aql/src/main/javacc/AQL.jj
+++ b/asterix-aql/src/main/javacc/AQL.jj
@@ -1865,12 +1865,9 @@
 	extendCurrentScope();
 }
 {
-    "let" varExp = Variable()
+    "let" varExp = Variable() ":=" beExp = Expression()
     {
       getCurrentScope().addNewVarSymbolToScope(varExp.getVar());
-	}
-     ":=" beExp = Expression()
-    {
       lc.setVarExpr(varExp);
       lc.setBeExpr(beExp);
       return lc;