From ae5d21227168e384123b0d5d5733c00cd244c45d Mon Sep 17 00:00:00 2001
From: romanb <romanb@625475ce-881a-0410-a577-b389adb331d8>
Date: Mon, 23 Mar 2009 17:39:33 +0000
Subject: [PATCH] [2.0] Parser work. Added double-dispatch functionality to AST
 node classes for use in the SqlWalker to reduce big if/else instanceof checks
 and for better maintainability. Also its less error-prone in the SqlWalker
 because its harder to miss a conditional case. Added new extensible DQL
 function implementation.

---
 .../ORM/Query/AST/AggregateExpression.php     |   5 +
 .../ORM/Query/AST/ArithmeticExpression.php    |   5 +
 .../ORM/Query/AST/ArithmeticFactor.php        |   5 +
 lib/Doctrine/ORM/Query/AST/ArithmeticTerm.php |   5 +
 .../ORM/Query/AST/BetweenExpression.php       |   5 +
 .../ORM/Query/AST/ComparisonExpression.php    |  26 +-
 .../ORM/Query/AST/ComparisonOperator.php      |   4 +
 .../ORM/Query/AST/ConditionalExpression.php   |   5 +
 .../ORM/Query/AST/ConditionalFactor.php       |   5 +
 .../ORM/Query/AST/ConditionalPrimary.php      |   5 +
 .../ORM/Query/AST/ConditionalTerm.php         |   5 +
 lib/Doctrine/ORM/Query/AST/DeleteClause.php   |   5 +
 .../ORM/Query/AST/DeleteStatement.php         |   5 +
 .../ORM/Query/AST/ExistsExpression.php        |  12 +-
 lib/Doctrine/ORM/Query/AST/FromClause.php     |   5 +
 lib/Doctrine/ORM/Query/AST/Function.php       |  17 -
 .../Query/AST/Functions/ConcatFunction.php    |  59 ++++
 .../ORM/Query/AST/Functions/FunctionNode.php  |  66 ++++
 .../ORM/Query/AST/Functions/LowerFunction.php |  44 +++
 .../Query/AST/Functions/SubstringFunction.php |  69 ++++
 .../ORM/Query/AST/Functions/TrimFunction.php  | 118 +++++++
 .../ORM/Query/AST/Functions/UpperFunction.php |  44 +++
 lib/Doctrine/ORM/Query/AST/GroupByClause.php  |   5 +
 lib/Doctrine/ORM/Query/AST/HavingClause.php   |   5 +
 .../AST/IdentificationVariableDeclaration.php |  12 +-
 lib/Doctrine/ORM/Query/AST/InExpression.php   |   5 +
 lib/Doctrine/ORM/Query/AST/IndexBy.php        |   5 +
 lib/Doctrine/ORM/Query/AST/InputParameter.php |   5 +
 lib/Doctrine/ORM/Query/AST/Join.php           |  94 +-----
 .../ORM/Query/AST/JoinPathExpression.php      |   5 +
 .../ORM/Query/AST/JoinVariableDeclaration.php |   5 +-
 lib/Doctrine/ORM/Query/AST/LikeExpression.php |   5 +
 lib/Doctrine/ORM/Query/AST/Node.php           |   5 +-
 .../Query/AST/NullComparisonExpression.php    |   5 +
 lib/Doctrine/ORM/Query/AST/OrderByClause.php  |   5 +
 lib/Doctrine/ORM/Query/AST/OrderByItem.php    |   5 +
 .../Query/AST/RangeVariableDeclaration.php    |  28 +-
 lib/Doctrine/ORM/Query/AST/SelectClause.php   |   5 +
 .../ORM/Query/AST/SelectExpression.php        |   5 +
 .../ORM/Query/AST/SelectStatement.php         |  10 +-
 .../Query/AST/SimpleArithmeticExpression.php  |   5 +
 .../ORM/Query/AST/SimpleSelectClause.php      |   5 +
 .../ORM/Query/AST/SimpleSelectExpression.php  |   5 +
 .../AST/SimpleStateFieldPathExpression.php    |   5 +
 .../Query/AST/StateFieldPathExpression.php    |   5 +
 lib/Doctrine/ORM/Query/AST/Subselect.php      |   5 +
 .../ORM/Query/AST/SubselectFromClause.php     |   5 +
 lib/Doctrine/ORM/Query/AST/UpdateClause.php   |   5 +
 lib/Doctrine/ORM/Query/AST/UpdateItem.php     |  26 +-
 .../ORM/Query/AST/UpdateStatement.php         |   5 +
 lib/Doctrine/ORM/Query/AST/WhereClause.php    |   5 +
 lib/Doctrine/ORM/Query/AbstractResult.php     |   1 -
 lib/Doctrine/ORM/Query/Parser.php             | 296 +++++++++++++-----
 lib/Doctrine/ORM/Query/SqlWalker.php          | 140 +++++----
 .../ORM/Query/LanguageRecognitionTest.php     |   3 +-
 .../ORM/Query/SelectSqlGenerationTest.php     |   8 +
 .../ORM/Query/UpdateSqlGenerationTest.php     |   1 -
 57 files changed, 957 insertions(+), 301 deletions(-)
 delete mode 100644 lib/Doctrine/ORM/Query/AST/Function.php
 create mode 100644 lib/Doctrine/ORM/Query/AST/Functions/ConcatFunction.php
 create mode 100644 lib/Doctrine/ORM/Query/AST/Functions/FunctionNode.php
 create mode 100644 lib/Doctrine/ORM/Query/AST/Functions/LowerFunction.php
 create mode 100644 lib/Doctrine/ORM/Query/AST/Functions/SubstringFunction.php
 create mode 100644 lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php
 create mode 100644 lib/Doctrine/ORM/Query/AST/Functions/UpperFunction.php

diff --git a/lib/Doctrine/ORM/Query/AST/AggregateExpression.php b/lib/Doctrine/ORM/Query/AST/AggregateExpression.php
index 4a355d5bf..17293b903 100644
--- a/lib/Doctrine/ORM/Query/AST/AggregateExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/AggregateExpression.php
@@ -38,4 +38,9 @@ class AggregateExpression extends Node
     {
         return $this->_functionName;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkAggregateExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ArithmeticExpression.php b/lib/Doctrine/ORM/Query/AST/ArithmeticExpression.php
index f49ec93cc..8c969cd45 100644
--- a/lib/Doctrine/ORM/Query/AST/ArithmeticExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/ArithmeticExpression.php
@@ -51,4 +51,9 @@ class ArithmeticExpression extends Node
     {
         return (bool) $this->_subselect;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkArithmeticExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ArithmeticFactor.php b/lib/Doctrine/ORM/Query/AST/ArithmeticFactor.php
index c2c9c94a1..9fcaef76d 100644
--- a/lib/Doctrine/ORM/Query/AST/ArithmeticFactor.php
+++ b/lib/Doctrine/ORM/Query/AST/ArithmeticFactor.php
@@ -38,4 +38,9 @@ class ArithmeticFactor extends Node
     {
         return $this->_nSigned;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkArithmeticFactor($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ArithmeticTerm.php b/lib/Doctrine/ORM/Query/AST/ArithmeticTerm.php
index 1ce611b19..1d2c18363 100644
--- a/lib/Doctrine/ORM/Query/AST/ArithmeticTerm.php
+++ b/lib/Doctrine/ORM/Query/AST/ArithmeticTerm.php
@@ -24,4 +24,9 @@ class ArithmeticTerm extends Node
     {
         return $this->_factors;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkArithmeticTerm($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/BetweenExpression.php b/lib/Doctrine/ORM/Query/AST/BetweenExpression.php
index 75a18c369..0b69eb281 100644
--- a/lib/Doctrine/ORM/Query/AST/BetweenExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/BetweenExpression.php
@@ -49,5 +49,10 @@ class BetweenExpression extends Node
     {
         return $this->_not;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkBetweenExpression($this);
+    }
 }
 
diff --git a/lib/Doctrine/ORM/Query/AST/ComparisonExpression.php b/lib/Doctrine/ORM/Query/AST/ComparisonExpression.php
index f2cf87ad7..915ddd0ad 100644
--- a/lib/Doctrine/ORM/Query/AST/ComparisonExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/ComparisonExpression.php
@@ -1,7 +1,22 @@
 <?php
-/* 
- * To change this template, choose Tools | Templates
- * and open the template in the editor.
+/*
+ *  $Id$
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the LGPL. For more information, see
+ * <http://www.doctrine-project.org>.
  */
 
 namespace Doctrine\ORM\Query\AST;
@@ -43,4 +58,9 @@ class ComparisonExpression extends Node
     {
         return $this->_operator;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkComparisonExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ComparisonOperator.php b/lib/Doctrine/ORM/Query/AST/ComparisonOperator.php
index 662da36c5..780f0f10b 100644
--- a/lib/Doctrine/ORM/Query/AST/ComparisonOperator.php
+++ b/lib/Doctrine/ORM/Query/AST/ComparisonOperator.php
@@ -35,4 +35,8 @@ namespace Doctrine\ORM\Query\AST;
  */
 class ComparisonOperator extends Node
 {
+    public function dispatch($sqlWalker)
+    {
+        ;
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ConditionalExpression.php b/lib/Doctrine/ORM/Query/AST/ConditionalExpression.php
index 1d019b531..ad2d57059 100644
--- a/lib/Doctrine/ORM/Query/AST/ConditionalExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/ConditionalExpression.php
@@ -24,4 +24,9 @@ class ConditionalExpression extends Node
     {
         return $this->_conditionalTerms;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkConditionalExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ConditionalFactor.php b/lib/Doctrine/ORM/Query/AST/ConditionalFactor.php
index e7f460980..b300b130c 100644
--- a/lib/Doctrine/ORM/Query/AST/ConditionalFactor.php
+++ b/lib/Doctrine/ORM/Query/AST/ConditionalFactor.php
@@ -31,4 +31,9 @@ class ConditionalFactor extends Node
     {
         return $this->_conditionalPrimary;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkConditionalFactor($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ConditionalPrimary.php b/lib/Doctrine/ORM/Query/AST/ConditionalPrimary.php
index 15f62d2f2..4d9e8b48a 100644
--- a/lib/Doctrine/ORM/Query/AST/ConditionalPrimary.php
+++ b/lib/Doctrine/ORM/Query/AST/ConditionalPrimary.php
@@ -45,4 +45,9 @@ class ConditionalPrimary extends Node
     {
         return (bool) $this->_conditionalExpression;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkConditionalPrimary($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ConditionalTerm.php b/lib/Doctrine/ORM/Query/AST/ConditionalTerm.php
index b665f81bd..05e3c2cab 100644
--- a/lib/Doctrine/ORM/Query/AST/ConditionalTerm.php
+++ b/lib/Doctrine/ORM/Query/AST/ConditionalTerm.php
@@ -24,4 +24,9 @@ class ConditionalTerm extends Node
     {
         return $this->_conditionalFactors;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkConditionalTerm($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/DeleteClause.php b/lib/Doctrine/ORM/Query/AST/DeleteClause.php
index 554d4098a..ef051665c 100644
--- a/lib/Doctrine/ORM/Query/AST/DeleteClause.php
+++ b/lib/Doctrine/ORM/Query/AST/DeleteClause.php
@@ -48,5 +48,10 @@ class DeleteClause extends Node
     {
         $this->_aliasIdentificationVariable = $alias;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkDeleteClause($this);
+    }
 }
 
diff --git a/lib/Doctrine/ORM/Query/AST/DeleteStatement.php b/lib/Doctrine/ORM/Query/AST/DeleteStatement.php
index 581a7500c..81f5e9c60 100644
--- a/lib/Doctrine/ORM/Query/AST/DeleteStatement.php
+++ b/lib/Doctrine/ORM/Query/AST/DeleteStatement.php
@@ -54,4 +54,9 @@ class DeleteStatement extends Node
     {
         return $this->_whereClause;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkDeleteStatement($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/ExistsExpression.php b/lib/Doctrine/ORM/Query/AST/ExistsExpression.php
index f532e6f02..6b4374b5c 100644
--- a/lib/Doctrine/ORM/Query/AST/ExistsExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/ExistsExpression.php
@@ -26,9 +26,19 @@ class ExistsExpression extends Node
         $this->_not = $bool;
     }
 
-    public function getNot()
+    public function isNot()
     {
         return $this->_not;
     }
+
+    public function getSubselect()
+    {
+        return $this->_subselect;
+    }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkExistsExpression($this);
+    }
 }
 
diff --git a/lib/Doctrine/ORM/Query/AST/FromClause.php b/lib/Doctrine/ORM/Query/AST/FromClause.php
index fff544fd6..5732f05d9 100644
--- a/lib/Doctrine/ORM/Query/AST/FromClause.php
+++ b/lib/Doctrine/ORM/Query/AST/FromClause.php
@@ -44,4 +44,9 @@ class FromClause extends Node
     {
         return $this->_identificationVariableDeclarations;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkFromClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/Function.php b/lib/Doctrine/ORM/Query/AST/Function.php
deleted file mode 100644
index 98b5451e8..000000000
--- a/lib/Doctrine/ORM/Query/AST/Function.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-/* 
- * To change this template, choose Tools | Templates
- * and open the template in the editor.
- */
-
-namespace Doctrine\ORM\Query\AST;
-
-/**
- * Description of Function
- *
- * @author robo
- */
-class FunctionNode extends Node
-{
-    private $_name;
-}
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/ConcatFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/ConcatFunction.php
new file mode 100644
index 000000000..583b9fe1f
--- /dev/null
+++ b/lib/Doctrine/ORM/Query/AST/Functions/ConcatFunction.php
@@ -0,0 +1,59 @@
+<?php
+/* 
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+namespace Doctrine\ORM\Query\AST\Functions;
+
+/**
+ * "CONCAT" "(" StringPrimary "," StringPrimary ")"
+ *
+ * @author robo
+ */
+class ConcatFunction extends FunctionNode
+{
+    private $_firstStringPrimary;
+    private $_secondStringPriamry;
+
+    public function getFirstStringPrimary()
+    {
+        return $this->_firstStringPrimary;
+    }
+
+    public function getSecondStringPrimary()
+    {
+        return $this->_secondStringPrimary;
+    }
+
+    /**
+     * @override
+     */
+    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
+    {
+        //TODO: Use platform to get SQL
+        $sql = 'CONCAT(' .
+                $sqlWalker->walkStringPrimary($this->_firstStringPrimary)
+                . ', ' .
+                $sqlWalker->walkStringPrimary($this->_secondStringPrimary)
+                . ')';
+        return $sql;
+    }
+
+    /**
+     * @override
+     */
+    public function parse(\Doctrine\ORM\Query\Parser $parser)
+    {
+        $lexer = $parser->getLexer();
+        $parser->match($lexer->lookahead['value']);
+        $parser->match('(');
+
+        $this->_firstStringPrimary = $parser->_StringPrimary();
+        $parser->match(',');
+        $this->_secondStringPrimary = $parser->_StringPrimary();
+
+        $parser->match(')');
+    }
+}
+
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/FunctionNode.php b/lib/Doctrine/ORM/Query/AST/Functions/FunctionNode.php
new file mode 100644
index 000000000..ce7733750
--- /dev/null
+++ b/lib/Doctrine/ORM/Query/AST/Functions/FunctionNode.php
@@ -0,0 +1,66 @@
+<?php
+/*
+ *  $Id$
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the LGPL. For more information, see
+ * <http://www.doctrine-project.org>.
+ */
+
+namespace Doctrine\ORM\Query\AST\Functions;
+
+use Doctrine\ORM\Query\AST\Node;
+
+/**
+ * Description of Function
+ *
+ * @author robo
+ */
+abstract class FunctionNode extends Node
+{
+    private $_name;
+    //private $_expressions = array();
+
+    public function __construct($name)
+    {
+        $this->_name = $name;
+    }
+
+    public function getName()
+    {
+        return $this->_name;
+    }
+
+    abstract public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker);
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkFunction($this);
+    }
+
+    //abstract public function parse(\Doctrine\ORM\Query\Parser $parser);
+
+/*
+    public function getExpressions()
+    {
+        return $this->_expressions;
+    }
+
+    public function setExpressions(array $expressions)
+    {
+        $this->_expressions = $expressions;
+    }
+ */
+}
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/LowerFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/LowerFunction.php
new file mode 100644
index 000000000..8577c7115
--- /dev/null
+++ b/lib/Doctrine/ORM/Query/AST/Functions/LowerFunction.php
@@ -0,0 +1,44 @@
+<?php
+/* 
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+namespace Doctrine\ORM\Query\AST\Functions;
+
+/**
+ * "LOWER" "(" StringPrimary ")"
+ *
+ * @author robo
+ */
+class LowerFunction extends FunctionNode
+{
+    private $_stringPrimary;
+
+    public function getStringPrimary()
+    {
+        return $this->_stringPrimary;
+    }
+
+    /**
+     * @override
+     */
+    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
+    {
+        //TODO: Use platform to get SQL
+        return 'LOWER(' . $sqlWalker->walkStringPrimary($this->_stringPrimary) . ')';
+    }
+
+    /**
+     * @override
+     */
+    public function parse(\Doctrine\ORM\Query\Parser $parser)
+    {
+        $lexer = $parser->getLexer();
+        $parser->match($lexer->lookahead['value']);
+        $parser->match('(');
+        $this->_stringPrimary = $parser->_StringPrimary();
+        $parser->match(')');
+    }
+}
+
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/SubstringFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/SubstringFunction.php
new file mode 100644
index 000000000..528b8ba45
--- /dev/null
+++ b/lib/Doctrine/ORM/Query/AST/Functions/SubstringFunction.php
@@ -0,0 +1,69 @@
+<?php
+/* 
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+namespace Doctrine\ORM\Query\AST\Functions;
+
+/**
+ * "SUBSTRING" "(" StringPrimary "," SimpleArithmeticExpression "," SimpleArithmeticExpression ")"
+ *
+ * @author robo
+ */
+class SubstringFunction extends FunctionNode
+{
+    private $_stringPrimary;
+    private $_firstSimpleArithmeticExpression;
+    private $_secondSimpleArithmeticExpression;
+
+    public function geStringPrimary()
+    {
+        return $this->_stringPrimary;
+    }
+
+    public function getSecondSimpleArithmeticExpression()
+    {
+        return $this->_secondSimpleArithmeticExpression;
+    }
+
+    public function getFirstSimpleArithmeticExpression()
+    {
+        return $this->_firstSimpleArithmeticExpression;
+    }
+
+    /**
+     * @override
+     */
+    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
+    {
+        //TODO: Use platform to get SQL
+        $sql = 'SUBSTRING(' .
+                $sqlWalker->walkStringPrimary($this->_stringPrimary)
+                . ', ' .
+                $sqlWalker->walkSimpleArithmeticExpression($this->_firstSimpleArithmeticExpression)
+                . ', ' .
+                $sqlWalker->walkSimpleArithmeticExpression($this->_secondSimpleArithmeticExpression)
+                . ')';
+        return $sql;
+    }
+
+    /**
+     * @override
+     */
+    public function parse(\Doctrine\ORM\Query\Parser $parser)
+    {
+        $lexer = $parser->getLexer();
+        $parser->match($lexer->lookahead['value']);
+        $parser->match('(');
+
+        $this->_stringPrimary = $parser->_StringPrimary();
+        $parser->match(',');
+        $this->_firstSimpleArithmeticExpression = $parser->_SimpleArithmeticExpression();
+        $parser->match(',');
+        $this->_secondSimpleArithmeticExpression = $parser->_SimpleArithmeticExpression();
+
+        $parser->match(')');
+    }
+}
+
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php
new file mode 100644
index 000000000..eed6a7764
--- /dev/null
+++ b/lib/Doctrine/ORM/Query/AST/Functions/TrimFunction.php
@@ -0,0 +1,118 @@
+<?php
+/* 
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+namespace Doctrine\ORM\Query\AST\Functions;
+
+use Doctrine\ORM\Query\Lexer;
+
+/**
+ * "TRIM" "(" [["LEADING" | "TRAILING" | "BOTH"] [char] "FROM"] StringPrimary ")"
+ *
+ * @author robo
+ */
+class TrimFunction extends FunctionNode
+{
+    private $_leading;
+    private $_trailing;
+    private $_both;
+    private $_trimChar;
+    private $_stringPrimary;
+
+    public function getStringPrimary()
+    {
+        return $this->_stringPrimary;
+    }
+
+    public function isLeading()
+    {
+        return $this->_leading;
+    }
+
+    public function setLeading($bool)
+    {
+        $this->_leading = $bool;
+    }
+
+    public function isTrailing()
+    {
+        return $this->_trailing;
+    }
+
+    public function setTrailing($bool)
+    {
+        $this->_trailing = $bool;
+    }
+
+    public function isBoth()
+    {
+        return $this->_both;
+    }
+
+    public function setBoth($bool)
+    {
+        $this->_both = $bool;
+    }
+
+    public function getTrimChar()
+    {
+        return $this->_trimChar;
+    }
+
+    public function setTrimChar($trimChar)
+    {
+        $this->_trimChar = $trimChar;
+    }
+
+    /**
+     * @override
+     */
+    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
+    {
+        $sql = 'TRIM(';
+        if ($this->_leading) $sql .= 'LEADING ';
+        else if ($this->_trailing) $sql .= 'TRAILING ';
+        else if ($this->_both) $sql .= 'BOTH ';
+        if ($this->_trimChar) $sql .= $this->_trimChar . ' '; //TODO: quote()
+        $sql .= 'FROM ' . $sqlWalker->walkStringPrimary($this->_stringPrimary);
+        $sql .= ')';
+        return $sql;
+    }
+
+    /**
+     * @override
+     */
+    public function parse(\Doctrine\ORM\Query\Parser $parser)
+    {
+        $lexer = $parser->getLexer();
+        $parser->match($lexer->lookahead['value']);
+        $parser->match('(');
+
+        if (strcasecmp('leading', $lexer->lookahead['value']) === 0) {
+            $parser->match($lexer->lookahead['value']);
+            $this->_leading = true;
+        } else if (strcasecmp('trailing', $lexer->lookahead['value']) === 0) {
+            $parser->match($lexer->lookahead['value']);
+            $this->_trailing = true;
+        } else if (strcasecmp('both', $lexer->lookahead['value']) === 0) {
+            $parser->match($lexer->lookahead['value']);
+            $this->_both = true;
+        }
+
+        if ($lexer->isNextToken(Lexer::T_STRING)) {
+            $parser->match(Lexer::T_STRING);
+            $this->_trimChar = $lexer->token['value'];
+        }
+
+        if ($this->_leading || $this->_trailing || $this->_both || $this->_trimChar) {
+            $parser->match(Lexer::T_FROM);
+        }
+
+        $this->_stringPrimary = $parser->_StringPrimary();
+        
+        $parser->match(')');
+    }
+    
+}
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/UpperFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/UpperFunction.php
new file mode 100644
index 000000000..6ff8bc1af
--- /dev/null
+++ b/lib/Doctrine/ORM/Query/AST/Functions/UpperFunction.php
@@ -0,0 +1,44 @@
+<?php
+/* 
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+namespace Doctrine\ORM\Query\AST\Functions;
+
+/**
+ * "UPPER" "(" StringPrimary ")"
+ *
+ * @author robo
+ */
+class UpperFunction extends FunctionNode
+{
+    private $_stringPrimary;
+
+    public function getStringPrimary()
+    {
+        return $this->_stringPrimary;
+    }
+
+    /**
+     * @override
+     */
+    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
+    {
+        //TODO: Use platform to get SQL
+        return 'UPPER(' . $sqlWalker->walkStringPrimary($this->_stringPrimary) . ')';
+    }
+
+    /**
+     * @override
+     */
+    public function parse(\Doctrine\ORM\Query\Parser $parser)
+    {
+        $lexer = $parser->getLexer();
+        $parser->match($lexer->lookahead['value']);
+        $parser->match('(');
+        $this->_stringPrimary = $parser->_StringPrimary();
+        $parser->match(')');
+    }
+}
+
diff --git a/lib/Doctrine/ORM/Query/AST/GroupByClause.php b/lib/Doctrine/ORM/Query/AST/GroupByClause.php
index 1715991db..58e7d0db3 100644
--- a/lib/Doctrine/ORM/Query/AST/GroupByClause.php
+++ b/lib/Doctrine/ORM/Query/AST/GroupByClause.php
@@ -24,4 +24,9 @@ class GroupByClause extends Node
     {
         return $this->_groupByItems;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkGroupByClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/HavingClause.php b/lib/Doctrine/ORM/Query/AST/HavingClause.php
index 887da736a..aaf74b4c8 100644
--- a/lib/Doctrine/ORM/Query/AST/HavingClause.php
+++ b/lib/Doctrine/ORM/Query/AST/HavingClause.php
@@ -24,4 +24,9 @@ class HavingClause extends Node
     {
         return $this->_conditionalExpression;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkHavingClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/IdentificationVariableDeclaration.php b/lib/Doctrine/ORM/Query/AST/IdentificationVariableDeclaration.php
index e84c5b778..148cf0420 100644
--- a/lib/Doctrine/ORM/Query/AST/IdentificationVariableDeclaration.php
+++ b/lib/Doctrine/ORM/Query/AST/IdentificationVariableDeclaration.php
@@ -63,16 +63,8 @@ class IdentificationVariableDeclaration extends Node
         return $this->_joinVariableDeclarations;
     }
 
-    /* REMOVE ME LATER. COPIED METHODS FROM SPLIT OF PRODUCTION INTO "AST" AND "PARSER" */
-    
-    public function buildSql()
+    public function dispatch($sqlWalker)
     {
-        $str = $this->_rangeVariableDeclaration->buildSql();
-
-        for ($i = 0, $l = count($this->_joinVariableDeclarations); $i < $l; $i++) {
-            $str .= ' ' . $this->_joinVariableDeclarations[$i]->buildSql();
-        }
-
-        return $str;
+        return $sqlWalker->walkIdentificationVariableDeclaration($this);
     }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/InExpression.php b/lib/Doctrine/ORM/Query/AST/InExpression.php
index 40a0802d7..6654791f6 100644
--- a/lib/Doctrine/ORM/Query/AST/InExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/InExpression.php
@@ -57,5 +57,10 @@ class InExpression extends Node
     {
         return $this->_pathExpression;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkInExpression($this);
+    }
 }
 
diff --git a/lib/Doctrine/ORM/Query/AST/IndexBy.php b/lib/Doctrine/ORM/Query/AST/IndexBy.php
index a51d53591..9caf9757a 100644
--- a/lib/Doctrine/ORM/Query/AST/IndexBy.php
+++ b/lib/Doctrine/ORM/Query/AST/IndexBy.php
@@ -44,4 +44,9 @@ class IndexBy extends Node
     {
         return $this->_simpleStateFieldPathExpression;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkIndexBy($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/InputParameter.php b/lib/Doctrine/ORM/Query/AST/InputParameter.php
index 013447570..b703d304c 100644
--- a/lib/Doctrine/ORM/Query/AST/InputParameter.php
+++ b/lib/Doctrine/ORM/Query/AST/InputParameter.php
@@ -51,4 +51,9 @@ class InputParameter extends Node
     {
         return $this->_position;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkInputParameter($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/Join.php b/lib/Doctrine/ORM/Query/AST/Join.php
index c0f42c3eb..0ea93ae9c 100644
--- a/lib/Doctrine/ORM/Query/AST/Join.php
+++ b/lib/Doctrine/ORM/Query/AST/Join.php
@@ -89,97 +89,9 @@ class Join extends Node
     {
         return $this->_conditionalExpression;
     }
-    
-    /* REMOVE ME LATER. COPIED METHODS FROM SPLIT OF PRODUCTION INTO "AST" AND "PARSER" */
-    
-    public function buildSql()
+
+    public function dispatch($sqlWalker)
     {
-        $join = '';
-
-        switch ($this->_joinType) {
-            case self::JOIN_TYPE_LEFT:
-                $join .= 'LEFT';
-                break;
-                
-            case self::JOIN_TYPE_LEFTOUTER:
-                $join .= 'LEFT OUTER';
-                break;
-                
-            case self::JOIN_TYPE_INNER:
-            default:
-                $join .= 'INNER';
-                break;
-        }
-        
-        $join .= ' JOIN ' . $this->_joinAssociationPathExpression->buildSql();
-        $condition = isset($this->_conditionalExpression)
-            ? $this->_conditionalExpression->buildSql() : '';
-        
-        switch ($this->whereType) {
-            case self::JOIN_WHERE_ON:
-                // Nothing to do here... =)
-                break;
-                
-            case self::JOIN_WHERE_WITH:
-            default:
-            
-                /*
-
-                TODO: Refactor to support split!!!
-
-                $parserResult = $this->_parser->getParserResult();
-        
-                // Get the connection for the component
-                $conn = $this->_em->getConnection();
-
-                // We need to build the join conditions. Retrieving AssociationMapping
-                $queryComponent = $this->_rangeVariableDeclaration->getQueryComponent();
-                $association = $queryComponent['relation'];
-                $joinColumns = array();
-                
-                if ($association->isOneToMany() || $association->isOneToOne()) {
-                    if ($association->isInverseSide()) {
-                        // joinColumns are found on the other (owning) side
-                        $targetClass = $this->_em->getClassMetadata($association->getTargetEntityName());
-                        $joinColumns = $targetClass->getAssociationMapping($association->getMappedByFieldName())
-                                ->getTargetToSourceKeyColumns();
-                    } else {
-                        $joinColumns = $association->getSourceToTargetKeyColumns();
-                    }
-                } else {
-                    //TODO: many-many
-                }
-               
-                $relationConditionExpression = '';
-        
-                // We have an array('localColumn' => 'foreignColumn', ...) here
-                foreach ($joinColumns as $localColumn => $foreignColumn) {
-                    // leftExpression = rightExpression
-        
-                    // Defining leftExpression
-                    $leftExpression = $conn->quoteIdentifier(
-                        $parserResult->getTableAliasFromComponentAlias($queryComponent['parent']) . '.' . $localColumn
-                    );
-        
-                    // Defining rightExpression
-                    $rightExpression = $conn->quoteIdentifier(
-                        $parserResult->getTableAliasFromComponentAlias(
-                            $this->_rangeVariableDeclaration->getIdentificationVariable()
-                        ) . '.' . $foreignColumn
-                     );
-        
-                     // Building the relation
-                     $relationConditionExpression .= (($relationConditionExpression != '') ? ' AND ' : '')
-                         . $leftExpression . ' = ' . $rightExpression;
-                }
-                
-                $sql .= ' ON ' . $relationConditionExpression;
-                $sql .= empty($conditionExpression) ? '' : ' AND (' . $conditionExpression . ')';
-                */
-
-                break;
-        }
-        
-        return $join . ' ON ' . $condition;
+        return $sqlWalker->walkJoin($this);
     }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/JoinPathExpression.php b/lib/Doctrine/ORM/Query/AST/JoinPathExpression.php
index 72f64e587..26899b9f5 100644
--- a/lib/Doctrine/ORM/Query/AST/JoinPathExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/JoinPathExpression.php
@@ -32,4 +32,9 @@ class JoinPathExpression extends Node
     {
         return $this->_assocField;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkJoinPathExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/JoinVariableDeclaration.php b/lib/Doctrine/ORM/Query/AST/JoinVariableDeclaration.php
index cfb4bff46..50545462a 100644
--- a/lib/Doctrine/ORM/Query/AST/JoinVariableDeclaration.php
+++ b/lib/Doctrine/ORM/Query/AST/JoinVariableDeclaration.php
@@ -52,9 +52,8 @@ class JoinVariableDeclaration extends Node
         return $this->_indexBy;
     }
 
-    /* REMOVE ME LATER. COPIED METHODS FROM SPLIT OF PRODUCTION INTO "AST" AND "PARSER" */
-    public function buildSql()
+    public function dispatch($sqlWalker)
     {
-        return $this->_join->buildSql() . (isset($this->_indexby) ? $this->_indexby->buildSql() . ' ' : '');
+        return $sqlWalker->walkJoinVariableDeclaration($this);
     }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/LikeExpression.php b/lib/Doctrine/ORM/Query/AST/LikeExpression.php
index 7959fbf1b..e87d5f437 100644
--- a/lib/Doctrine/ORM/Query/AST/LikeExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/LikeExpression.php
@@ -45,4 +45,9 @@ class LikeExpression extends Node
     {
         return $this->_escapeChar;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkLikeExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/Node.php b/lib/Doctrine/ORM/Query/AST/Node.php
index 87765836b..3b6df29a2 100644
--- a/lib/Doctrine/ORM/Query/AST/Node.php
+++ b/lib/Doctrine/ORM/Query/AST/Node.php
@@ -16,7 +16,7 @@
  *
  * This software consists of voluntary contributions made by many individuals
  * and is licensed under the LGPL. For more information, see
- * <http://www.phpdoctrine.org>.
+ * <http://www.doctrine-project.org>.
  */
 
 namespace Doctrine\ORM\Query\AST;
@@ -27,10 +27,11 @@ namespace Doctrine\ORM\Query\AST;
  * @author      Guilherme Blanco <guilhermeblanco@hotmail.com>
  * @author      Janne Vanhala <jpvanhal@cc.hut.fi>
  * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
- * @link        http://www.phpdoctrine.org
+ * @link        http://www.doctrine-project.org
  * @since       2.0
  * @version     $Revision$
  */
 abstract class Node
 {
+    abstract public function dispatch($sqlWalker);
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/NullComparisonExpression.php b/lib/Doctrine/ORM/Query/AST/NullComparisonExpression.php
index 8ba4d90cb..ffac4ba61 100644
--- a/lib/Doctrine/ORM/Query/AST/NullComparisonExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/NullComparisonExpression.php
@@ -35,5 +35,10 @@ class NullComparisonExpression extends Node
     {
         return $this->_not;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkNullComparisonExpression($this);
+    }
 }
 
diff --git a/lib/Doctrine/ORM/Query/AST/OrderByClause.php b/lib/Doctrine/ORM/Query/AST/OrderByClause.php
index c8e3f5734..b38ad7e88 100644
--- a/lib/Doctrine/ORM/Query/AST/OrderByClause.php
+++ b/lib/Doctrine/ORM/Query/AST/OrderByClause.php
@@ -24,4 +24,9 @@ class OrderByClause extends Node
     {
         return $this->_orderByItems;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkOrderByClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/OrderByItem.php b/lib/Doctrine/ORM/Query/AST/OrderByItem.php
index 315e5e446..f452419a1 100644
--- a/lib/Doctrine/ORM/Query/AST/OrderByItem.php
+++ b/lib/Doctrine/ORM/Query/AST/OrderByItem.php
@@ -46,4 +46,9 @@ class OrderByItem extends Node
     {
         return $this->_desc;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkOrderByItem($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/RangeVariableDeclaration.php b/lib/Doctrine/ORM/Query/AST/RangeVariableDeclaration.php
index 07f689695..52700795b 100644
--- a/lib/Doctrine/ORM/Query/AST/RangeVariableDeclaration.php
+++ b/lib/Doctrine/ORM/Query/AST/RangeVariableDeclaration.php
@@ -16,7 +16,7 @@
  *
  * This software consists of voluntary contributions made by many individuals
  * and is licensed under the LGPL. For more information, see
- * <http://www.phpdoctrine.org>.
+ * <http://www.doctrine-project.org>.
  */
 
 namespace Doctrine\ORM\Query\AST;
@@ -26,7 +26,7 @@ namespace Doctrine\ORM\Query\AST;
  *
  * @author      Guilherme Blanco <guilhermeblanco@hotmail.com>
  * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
- * @link        http://www.phpdoctrine.org
+ * @link        http://www.doctrine-project.org
  * @since       2.0
  * @version     $Revision$
  */
@@ -58,27 +58,9 @@ class RangeVariableDeclaration extends Node
     {
         return $this->_classMetadata;
     }
-    
-    /* REMOVE ME LATER. COPIED METHODS FROM SPLIT OF PRODUCTION INTO "AST" AND "PARSER" */
-    public function buildSql()
+
+    public function dispatch($sqlWalker)
     {
-        // Retrieving connection
-        $conn = $this->_parserResult->getEntityManager()->getConnection();
-        
-        // Component alias
-        $componentAlias = $this->_aliasIdentificationVariable;
-
-        // Retrieving required information
-        try {
-            $queryComponent = $this->_parserResult->getQueryComponent($componentAlias);
-            $classMetadata = $queryComponent['metadata'];
-        } catch (Doctrine_Exception $e) {
-            $this->_parser->semanticalError($e->getMessage());
-
-            return;
-        }
-
-        return $conn->quoteIdentifier($classMetadata->getTableName()) . ' '
-             . $conn->quoteIdentifier($this->_parserResult->getTableAliasFromComponentAlias($componentAlias));
+        return $sqlWalker->walkRangeVariableDeclaration($this);
     }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SelectClause.php b/lib/Doctrine/ORM/Query/AST/SelectClause.php
index 3c96dcc4a..cbde46c06 100644
--- a/lib/Doctrine/ORM/Query/AST/SelectClause.php
+++ b/lib/Doctrine/ORM/Query/AST/SelectClause.php
@@ -69,4 +69,9 @@ class SelectClause extends Node
     {
         return is_object($value) ? $value->buildSql() : $value;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSelectClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SelectExpression.php b/lib/Doctrine/ORM/Query/AST/SelectExpression.php
index a107fe248..055517d9e 100644
--- a/lib/Doctrine/ORM/Query/AST/SelectExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/SelectExpression.php
@@ -52,4 +52,9 @@ class SelectExpression extends Node
     {
         return $this->_fieldIdentificationVariable;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSelectExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SelectStatement.php b/lib/Doctrine/ORM/Query/AST/SelectStatement.php
index 7d7629ff2..a9edeb449 100644
--- a/lib/Doctrine/ORM/Query/AST/SelectStatement.php
+++ b/lib/Doctrine/ORM/Query/AST/SelectStatement.php
@@ -80,14 +80,8 @@ class SelectStatement extends Node
         return $this->_orderByClause;
     }
     
-    /* REMOVE ME LATER. COPIED METHODS FROM SPLIT OF PRODUCTION INTO "AST" AND "PARSER" */
-    
-    public function buildSql()
+    public function dispatch($sqlWalker)
     {
-        return $this->_selectClause->buildSql() . ' ' . $this->_fromClause->buildSql()
-             . (($this->_whereClause !== null) ? ' ' . $this->_whereClause->buildSql() : '')
-             . (($this->_groupByClause !== null) ? ' ' . $this->_groupByClause->buildSql() : '')
-             . (($this->_havingClause !== null) ? ' ' . $this->_havingClause->buildSql() : '')
-             . (($this->_orderByClause !== null) ? ' ' . $this->_orderByClause->buildSql() : '');
+        return $sqlWalker->walkSelectStatement($this);
     }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SimpleArithmeticExpression.php b/lib/Doctrine/ORM/Query/AST/SimpleArithmeticExpression.php
index 6f4b0e8e9..13dd77045 100644
--- a/lib/Doctrine/ORM/Query/AST/SimpleArithmeticExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/SimpleArithmeticExpression.php
@@ -24,4 +24,9 @@ class SimpleArithmeticExpression extends Node
     {
         return $this->_terms;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSimpleArithmeticExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SimpleSelectClause.php b/lib/Doctrine/ORM/Query/AST/SimpleSelectClause.php
index c3a563a3f..da41a5e02 100644
--- a/lib/Doctrine/ORM/Query/AST/SimpleSelectClause.php
+++ b/lib/Doctrine/ORM/Query/AST/SimpleSelectClause.php
@@ -55,4 +55,9 @@ class SimpleSelectClause extends Node
     {
         return $this->_simpleSelectExpression;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSimpleSelectClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SimpleSelectExpression.php b/lib/Doctrine/ORM/Query/AST/SimpleSelectExpression.php
index 6ab5f9222..0cb90e37c 100644
--- a/lib/Doctrine/ORM/Query/AST/SimpleSelectExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/SimpleSelectExpression.php
@@ -55,4 +55,9 @@ class SimpleSelectExpression extends Node
     {
         $this->_fieldIdentificationVariable = $fieldAlias;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSimpleSelectExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SimpleStateFieldPathExpression.php b/lib/Doctrine/ORM/Query/AST/SimpleStateFieldPathExpression.php
index e2508534c..f8a0628bb 100644
--- a/lib/Doctrine/ORM/Query/AST/SimpleStateFieldPathExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/SimpleStateFieldPathExpression.php
@@ -51,4 +51,9 @@ class SimpleStateFieldPathExpression extends Node
     {
         return $this->_simpleStateField;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSimpleStateFieldPathExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/StateFieldPathExpression.php b/lib/Doctrine/ORM/Query/AST/StateFieldPathExpression.php
index 6e464d847..9aa589fd6 100644
--- a/lib/Doctrine/ORM/Query/AST/StateFieldPathExpression.php
+++ b/lib/Doctrine/ORM/Query/AST/StateFieldPathExpression.php
@@ -95,4 +95,9 @@ class StateFieldPathExpression extends Node
     {
         $this->_collectionValuedAssociationFields[$part] = true;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkStateFieldPathExpression($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/Subselect.php b/lib/Doctrine/ORM/Query/AST/Subselect.php
index 32dbe1e41..5be8c03ce 100644
--- a/lib/Doctrine/ORM/Query/AST/Subselect.php
+++ b/lib/Doctrine/ORM/Query/AST/Subselect.php
@@ -95,4 +95,9 @@ class Subselect extends Node
     {
         $this->_orderByClause = $orderByClause;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSubselect($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/SubselectFromClause.php b/lib/Doctrine/ORM/Query/AST/SubselectFromClause.php
index f19f421c1..c7b055978 100644
--- a/lib/Doctrine/ORM/Query/AST/SubselectFromClause.php
+++ b/lib/Doctrine/ORM/Query/AST/SubselectFromClause.php
@@ -44,4 +44,9 @@ class SubselectFromClause extends Node
     {
         return $this->_identificationVariableDeclarations;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkSubselectFromClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/UpdateClause.php b/lib/Doctrine/ORM/Query/AST/UpdateClause.php
index 8c5bbaf5b..2dadabfac 100644
--- a/lib/Doctrine/ORM/Query/AST/UpdateClause.php
+++ b/lib/Doctrine/ORM/Query/AST/UpdateClause.php
@@ -40,5 +40,10 @@ class UpdateClause extends Node
     {
         return $this->_updateItems;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkUpdateClause($this);
+    }
 }
 
diff --git a/lib/Doctrine/ORM/Query/AST/UpdateItem.php b/lib/Doctrine/ORM/Query/AST/UpdateItem.php
index 517e43ef5..fb0c78370 100644
--- a/lib/Doctrine/ORM/Query/AST/UpdateItem.php
+++ b/lib/Doctrine/ORM/Query/AST/UpdateItem.php
@@ -1,7 +1,22 @@
 <?php
-/* 
- * To change this template, choose Tools | Templates
- * and open the template in the editor.
+/*
+ *  $Id$
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the LGPL. For more information, see
+ * <http://www.doctrine-project.org>.
  */
 
 namespace Doctrine\ORM\Query\AST;
@@ -42,5 +57,10 @@ class UpdateItem extends Node
     {
         return $this->_newValue;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkUpdateItem($this);
+    }
 }
 
diff --git a/lib/Doctrine/ORM/Query/AST/UpdateStatement.php b/lib/Doctrine/ORM/Query/AST/UpdateStatement.php
index fa9092efc..3f1399db2 100644
--- a/lib/Doctrine/ORM/Query/AST/UpdateStatement.php
+++ b/lib/Doctrine/ORM/Query/AST/UpdateStatement.php
@@ -54,4 +54,9 @@ class UpdateStatement extends Node
     {
         return $this->_whereClause;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkUpdateStatement($this);
+    }
 }    
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AST/WhereClause.php b/lib/Doctrine/ORM/Query/AST/WhereClause.php
index 5d19dbd05..33db272af 100644
--- a/lib/Doctrine/ORM/Query/AST/WhereClause.php
+++ b/lib/Doctrine/ORM/Query/AST/WhereClause.php
@@ -24,4 +24,9 @@ class WhereClause extends Node
     {
         return $this->_conditionalExpression;
     }
+
+    public function dispatch($sqlWalker)
+    {
+        return $sqlWalker->walkWhereClause($this);
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/AbstractResult.php b/lib/Doctrine/ORM/Query/AbstractResult.php
index 77d172410..2ff4c17d8 100644
--- a/lib/Doctrine/ORM/Query/AbstractResult.php
+++ b/lib/Doctrine/ORM/Query/AbstractResult.php
@@ -1,5 +1,4 @@
 <?php
-
 /*
  *  $Id: Cache.php 3938 2008-03-06 19:36:50Z romanb $
  *
diff --git a/lib/Doctrine/ORM/Query/Parser.php b/lib/Doctrine/ORM/Query/Parser.php
index 48a96dd74..24fbb0104 100644
--- a/lib/Doctrine/ORM/Query/Parser.php
+++ b/lib/Doctrine/ORM/Query/Parser.php
@@ -21,6 +21,7 @@
 
 namespace Doctrine\ORM\Query;
 
+use Doctrine\Common\DoctrineException;
 use Doctrine\ORM\Query\AST;
 use Doctrine\ORM\Query\Exec;
 
@@ -40,6 +41,32 @@ class Parser
 {
     const SCALAR_QUERYCOMPONENT_ALIAS = 'dctrn';
 
+    /** Maps registered string function names to class names. */
+    private static $_STRING_FUNCTIONS = array(
+        'concat' => 'Doctrine\ORM\Query\AST\Functions\ConcatFunction',
+        'substring' => 'Doctrine\ORM\Query\AST\Functions\SubstringFunction',
+        'trim' => 'Doctrine\ORM\Query\AST\Functions\TrimFunction',
+        'lower' => 'Doctrine\ORM\Query\AST\Functions\LowerFunction',
+        'upper' => 'Doctrine\ORM\Query\AST\Functions\UpperFunction'
+    );
+
+    /** Maps registered numeric function names to class names. */
+    private static $_NUMERIC_FUNCTIONS = array(
+        'length' => 'Doctrine\ORM\Query\AST\Functions\LengthFunction',
+        'locate' => 'Doctrine\ORM\Query\AST\Functions\LocateFunction',
+        'abs' => 'Doctrine\ORM\Query\AST\Functions\AbsFunction',
+        'sqrt' => 'Doctrine\ORM\Query\AST\Functions\SqrtFunction',
+        'mod' => 'Doctrine\ORM\Query\AST\Functions\ModFunction',
+        'size' => 'Doctrine\ORM\Query\AST\Functions\SizeFunction'
+    );
+
+    /** Maps registered datetime function names to class names. */
+    private static $_DATETIME_FUNCTIONS = array(
+        'current_date' => 'Doctrine\ORM\Query\AST\Functions\CurrentDateFunction',
+        'current_time' => 'Doctrine\ORM\Query\AST\Functions\CurrentTimeFunction',
+        'current_timestamp' => 'Doctrine\ORM\Query\AST\Functions\CurrentTimestampFunction'
+    );
+
     /**
      * The minimum number of tokens read after last detected error before
      * another error can be reported.
@@ -713,41 +740,6 @@ class Parser
         return $this->_lexer->token['value'];
     }
 
-    /**
-     * Special rule that acceps all kinds of path expressions.
-     */
-    /*private function _StateFieldPathExpression()
-    {
-        $this->match(Lexer::T_IDENTIFIER);
-        $parts = array($this->_lexer->token['value']);
-        while ($this->_lexer->isNextToken('.')) {
-            $this->match('.');
-            $this->match(Lexer::T_IDENTIFIER);
-            $parts[] = $this->_lexer->token['value'];
-        }
-        $pathExpression = new AST\StateFieldPathExpression($parts);
-        return $pathExpression;
-    }*/
-
-    /**
-     * Special rule that acceps all kinds of path expressions. and defers their
-     * semantical checking until the FROM part has been parsed completely (joins inclusive).
-     * Mainly used for path expressions in the SelectExpressions.
-     */
-    /*private function _PathExpressionInSelect()
-    {
-        $this->match(Lexer::T_IDENTIFIER);
-        $parts = array($this->_lexer->token['value']);
-        while ($this->_lexer->isNextToken('.')) {
-            $this->match('.');
-            $this->match(Lexer::T_IDENTIFIER);
-            $parts[] = $this->_lexer->token['value'];
-        }
-        $expr = new AST\StateFieldPathExpression($parts);
-        $this->_pendingPathExpressionsInSelect[] = $expr;
-        return $expr;
-    }*/
-
     /**
      * JoinVariableDeclaration ::= Join [IndexBy]
      */
@@ -1231,23 +1223,138 @@ class Parser
     }
 
     /**
-     * SIMPLIFIED FROM BNF FOR NOW
-     * ComparisonExpression ::= ArithmeticExpression ComparisonOperator ( QuantifiedExpression | ArithmeticExpression )
+     * ComparisonExpression ::=
+     *          ArithmeticExpression ComparisonOperator (QuantifiedExpression | ArithmeticExpression) |
+     *          StringExpression ComparisonOperator (StringExpression | QuantifiedExpression) |
+     *          BooleanExpression ("=" | "<>" | "!=") (BooleanExpression | QuantifiedExpression) |
+     *          EnumExpression ("=" | "<>" | "!=") (EnumExpression | QuantifiedExpression) |
+     *          DatetimeExpression ComparisonOperator (DatetimeExpression | QuantifiedExpression) |
+     *          EntityExpression ("=" | "<>") (EntityExpression | QuantifiedExpression)
      */
     private function _ComparisonExpression()
     {
-        $leftExpr = $this->_ArithmeticExpression();
-        $operator = $this->_ComparisonOperator();
-        if ($this->_lexer->lookahead['type'] === Lexer::T_ALL ||
-                $this->_lexer->lookahead['type'] === Lexer::T_ANY ||
-                $this->_lexer->lookahead['type'] === Lexer::T_SOME) {
-            $rightExpr = $this->_QuantifiedExpression();
-        } else {
+        $peek = $this->_lexer->glimpse();
+
+        if ($this->_lexer->isNextToken(Lexer::T_INPUT_PARAMETER)) {
+            if ($this->_isComparisonOperator($peek)) {
+                $this->match(Lexer::T_INPUT_PARAMETER);
+                $leftExpr = new AST\InputParameter($this->_lexer->token['value']);
+            } else {
+                $leftExpr = $this->_ArithmeticExpression();
+            }
+            $operator = $this->_ComparisonOperator();
             $rightExpr = $this->_ArithmeticExpression();
+            //...
         }
+        else if ($this->_lexer->isNextToken('(') && $peek['type'] == Lexer::T_SELECT) {
+            $leftExpr = $this->_Subselect();
+            //...
+        }
+        else if ($this->_lexer->isNextToken(Lexer::T_IDENTIFIER) && $peek['value'] == '(') {
+            $peek2 = $this->_peekBeyond(')');
+            if ($this->_isComparisonOperator($peek2)) {
+                if ($this->_isStringFunction($this->_lexer->lookahead['value'])) {
+                    $leftExpr = $this->_FunctionsReturningStrings();
+                    $operator = $this->_ComparisonOperator();
+                    if ($this->_lexer->lookahead['type'] === Lexer::T_ALL ||
+                            $this->_lexer->lookahead['type'] === Lexer::T_ANY ||
+                            $this->_lexer->lookahead['type'] === Lexer::T_SOME) {
+                        $rightExpr = $this->_QuantifiedExpression();
+                    } else {
+                        $rightExpr = $this->_StringPrimary();
+                    }
+                } else if ($this->_isNumericFunction($this->_lexer->lookahead['value'])) {
+                    $leftExpr = $this->_FunctionsReturningNumerics();
+                    $operator = $this->_ComparisonOperator();
+                    if ($this->_lexer->lookahead['type'] === Lexer::T_ALL ||
+                            $this->_lexer->lookahead['type'] === Lexer::T_ANY ||
+                            $this->_lexer->lookahead['type'] === Lexer::T_SOME) {
+                        $rightExpr = $this->_QuantifiedExpression();
+                    } else {
+                        $rightExpr = $this->_ArithmeticExpression();
+                    }
+                } else {
+                    $leftExpr = $this->_FunctionsReturningDatetime();
+                    $operator = $this->_ComparisonOperator();
+                    if ($this->_lexer->lookahead['type'] === Lexer::T_ALL ||
+                            $this->_lexer->lookahead['type'] === Lexer::T_ANY ||
+                            $this->_lexer->lookahead['type'] === Lexer::T_SOME) {
+                        $rightExpr = $this->_QuantifiedExpression();
+                    } else {
+                        $rightExpr = $this->_DatetimePrimary();
+                    }
+                }
+            } else {
+                $leftExpr = $this->_ArithmeticExpression();
+                $operator = $this->_ComparisonOperator();
+                if ($this->_lexer->lookahead['type'] === Lexer::T_ALL ||
+                        $this->_lexer->lookahead['type'] === Lexer::T_ANY ||
+                        $this->_lexer->lookahead['type'] === Lexer::T_SOME) {
+                    $rightExpr = $this->_QuantifiedExpression();
+                } else {
+                    $rightExpr = $this->_StringExpression();
+                }
+            }
+        }
+        else if ($this->_isAggregateFunction($this->_lexer->lookahead)) {
+            $leftExpr = $this->_StringExpression();
+            $operator = $this->_ComparisonOperator();
+            if ($this->_lexer->lookahead['type'] === Lexer::T_ALL ||
+                    $this->_lexer->lookahead['type'] === Lexer::T_ANY ||
+                    $this->_lexer->lookahead['type'] === Lexer::T_SOME) {
+                $rightExpr = $this->_QuantifiedExpression();
+            } else {
+                $rightExpr = $this->_StringExpression();
+            }
+        }
+        else {
+            $leftExpr = $this->_ArithmeticExpression();
+            $operator = $this->_ComparisonOperator();
+            if ($this->_lexer->lookahead['type'] === Lexer::T_ALL ||
+                    $this->_lexer->lookahead['type'] === Lexer::T_ANY ||
+                    $this->_lexer->lookahead['type'] === Lexer::T_SOME) {
+                $rightExpr = $this->_QuantifiedExpression();
+            } else {
+                $rightExpr = $this->_ArithmeticExpression();
+            }
+        }
+
         return new AST\ComparisonExpression($leftExpr, $operator, $rightExpr);
     }
 
+    private function _isStringFunction($funcName)
+    {
+        return isset(self::$_STRING_FUNCTIONS[strtolower($funcName)]);
+    }
+
+    private function _isNumericFunction($funcName)
+    {
+        return isset(self::$_NUMERIC_FUNCTIONS[strtolower($funcName)]);
+    }
+
+    private function _isDatetimeFunction($funcName)
+    {
+        return isset(self::$_DATETIME_FUNCTIONS[strtolower($funcName)]);
+    }
+
+    private function _peekBeyond($token)
+    {
+        $peek = $this->_lexer->peek();
+        while ($peek['value'] != $token) {
+            $peek = $this->_lexer->peek();
+        }
+        $peek = $this->_lexer->peek();
+        $this->_lexer->resetPeek();
+        return $peek;
+    }
+
+    private function _isComparisonOperator($token)
+    {
+        $value = $token['value'];
+        return $value == '=' || $value == '<' || $value == '<=' || $value == '<>' ||
+                $value == '>' || $value == '>=' || $value == '!=';
+    }
+
     /**
      * ArithmeticExpression ::= SimpleArithmeticExpression | "(" Subselect ")"
      */
@@ -1257,7 +1364,9 @@ class Parser
         if ($this->_lexer->lookahead['value'] === '(') {
             $peek = $this->_lexer->glimpse();
             if ($peek['type'] === Lexer::T_SELECT) {
+                $this->match('(');
                 $expr->setSubselect($this->_Subselect());
+                $this->match(')');
                 return $expr;
             }
         }
@@ -1526,7 +1635,7 @@ class Parser
             case Lexer::T_IDENTIFIER:
                 $peek = $this->_lexer->glimpse();
                 if ($peek['value'] == '(') {
-                    return $this->_FunctionsReturningStrings();
+                    return $this->_FunctionsReturningNumerics();
                 }
                 return $this->_StateFieldPathExpression();
             case Lexer::T_INPUT_PARAMETER:
@@ -1548,7 +1657,7 @@ class Parser
                     $this->syntaxError();
                 }
         }
-        throw \Doctrine\Common\DoctrineException::updateMe("Not yet implemented2.");
+        throw DoctrineException::updateMe("Not yet implemented2.");
         //TODO...
     }
 
@@ -1562,42 +1671,51 @@ class Parser
      */
     private function _FunctionsReturningStrings()
     {
-        switch (strtoupper($this->_lexer->lookahead['value'])) {
-            case 'CONCAT':
-                
-                break;
-            case 'SUBSTRING':
-
-                break;
-            case 'TRIM':
-                //TODO: This is not complete! See BNF
-                $this->match($this->_lexer->lookahead['value']);
-                $this->match('(');
-                $func = $this->_StringPrimary();
-                $this->match(')');
-                return $func;
-            case 'LOWER':
-
-                break;
-            case 'UPPER':
-
-            default:
-                $this->syntaxError('CONCAT, SUBSTRING, TRIM or UPPER');
-        }
+        $funcNameLower = strtolower($this->_lexer->lookahead['value']);
+        $funcClass = self::$_STRING_FUNCTIONS[$funcNameLower];
+        $function = new $funcClass($funcNameLower);
+        $function->parse($this);
+        return $function;
     }
 
+    /**
+     * PortableFunctionsReturningNumerics ::=
+     *      "LENGTH" "(" StringPrimary ")" |
+     *      "LOCATE" "(" StringPrimary "," StringPrimary ["," SimpleArithmeticExpression]")" |
+     *      "ABS" "(" SimpleArithmeticExpression ")" |
+     *      "SQRT" "(" SimpleArithmeticExpression ")" |
+     *      "MOD" "(" SimpleArithmeticExpression "," SimpleArithmeticExpression ")" |
+     *      "SIZE" "(" CollectionValuedPathExpression ")"
+     */
+    private function _FunctionsReturningNumerics()
+    {
+        $funcNameLower = strtolower($this->_lexer->lookahead['value']);
+        $funcClass = self::$_NUMERIC_FUNCTIONS[$funcNameLower];
+        $function = new $funcClass($funcNameLower);
+        $function->parse($this);
+        return $function;
+    }
+
+    /**
+     * PortableFunctionsReturningDateTime ::= "CURRENT_DATE" | "CURRENT_TIME" | "CURRENT_TIMESTAMP"
+     */
+    public function _FunctionsReturningDatetime()
+    {
+        $funcNameLower = strtolower($this->_lexer->lookahead['value']);
+        $funcClass = self::$_DATETIME_FUNCTIONS[$funcNameLower];
+        $function = new $funcClass($funcNameLower);
+        $function->parse($this);
+        return $function;
+    }
+
+    /**
+     * Checks whether the given token type indicates an aggregate function.
+     */
     private function _isAggregateFunction($tokenType)
     {
-        switch ($tokenType) {
-            case Lexer::T_AVG:
-            case Lexer::T_MIN:
-            case Lexer::T_MAX:
-            case Lexer::T_SUM:
-            case Lexer::T_COUNT:
-                return true;
-            default:
-                return false;
-        }
+        return $tokenType == Lexer::T_AVG || $tokenType == Lexer::T_MIN ||
+                $tokenType == Lexer::T_MAX || $tokenType == Lexer::T_SUM ||
+                $tokenType == Lexer::T_COUNT;
     }
 
     /**
@@ -1674,7 +1792,10 @@ class Parser
         if ($this->_lexer->lookahead['value'] === '(') {
             $peek = $this->_lexer->glimpse();
             if ($peek['type'] === Lexer::T_SELECT) {
-                return $this->_Subselect();
+                $this->match('(');
+                $expr = $this->_Subselect();
+                $this->match(')');
+                return $expr;
             }
         }
         return $this->_StringPrimary();
@@ -1683,7 +1804,7 @@ class Parser
     /**
      * StringPrimary ::= StateFieldPathExpression | string | InputParameter | FunctionsReturningStrings | AggregateExpression
      */
-    private function _StringPrimary()
+    public function _StringPrimary()
     {
         if ($this->_lexer->lookahead['type'] === Lexer::T_IDENTIFIER) {
             $peek = $this->_lexer->glimpse();
@@ -1704,4 +1825,19 @@ class Parser
             $this->syntaxError('StateFieldPathExpression | string | InputParameter | FunctionsReturningStrings | AggregateExpression');
         }
     }
+
+    public static function registerStringFunction($name, $class)
+    {
+        self::$_STRING_FUNCTIONS[$name] = $class;
+    }
+
+    public static function registerNumericFunction($name, $class)
+    {
+        self::$_NUMERIC_FUNCTIONS[$name] = $class;
+    }
+
+    public static function registerDatetimeFunction($name, $class)
+    {
+        self::$_DATETIME_FUNCTIONS[$name] = $class;
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Query/SqlWalker.php b/lib/Doctrine/ORM/Query/SqlWalker.php
index 4e072c526..af9644e56 100644
--- a/lib/Doctrine/ORM/Query/SqlWalker.php
+++ b/lib/Doctrine/ORM/Query/SqlWalker.php
@@ -78,7 +78,7 @@ class SqlWalker
     public function walkSelectClause($selectClause)
     {
         return 'SELECT ' . (($selectClause->isDistinct()) ? 'DISTINCT ' : '')
-                . implode(', ', array_map(array(&$this, 'walkSelectExpression'),
+                . implode(', ', array_map(array($this, 'walkSelectExpression'),
                         $selectClause->getSelectExpressions()));
     }
 
@@ -98,6 +98,11 @@ class SqlWalker
         return $sql;
     }
 
+    public function walkFunction($function)
+    {
+        return $function->getSql($this);
+    }
+
     /**
      * Walks down a JoinVariableDeclaration AST node and creates the corresponding SQL.
      *
@@ -108,8 +113,7 @@ class SqlWalker
     {
         $join = $joinVarDecl->getJoin();
         $joinType = $join->getJoinType();
-        if ($joinType == AST\Join::JOIN_TYPE_LEFT ||
-                $joinType == AST\Join::JOIN_TYPE_LEFTOUTER) {
+        if ($joinType == AST\Join::JOIN_TYPE_LEFT || $joinType == AST\Join::JOIN_TYPE_LEFTOUTER) {
             $sql = ' LEFT JOIN ';
         } else {
             $sql = ' INNER JOIN ';
@@ -177,9 +181,9 @@ class SqlWalker
                 $sql .= $sqlTableAlias . '.' . $class->getColumnName($fieldName) .
                         ' AS ' . $sqlTableAlias . '__' . $class->getColumnName($fieldName);
             } else if ($pathExpression->isSimpleStateFieldAssociationPathExpression()) {
-                \Doctrine\Common\DoctrineException::updateMe("Not yet implemented.");
+                throw DoctrineException::updateMe("Not yet implemented.");
             } else {
-                \Doctrine\Common\DoctrineException::updateMe("Encountered invalid PathExpression during SQL construction.");
+                throw DoctrineException::updateMe("Encountered invalid PathExpression during SQL construction.");
             }
         }
         else if ($selectExpression->getExpression() instanceof AST\AggregateExpression) {
@@ -355,9 +359,16 @@ class SqlWalker
                 . ' = ';
 
         $newValue = $updateItem->getNewValue();
-        if ($newValue instanceof AST\InputParameter) {
-            $sql .= $newValue->isNamed() ? ':' . $newValue->getName() : '?';
-        } // TODO: else if ...
+
+        if ($newValue instanceof AST\Node) {
+            $sql .= $newValue->dispatch($this);
+        } else if (is_string($newValue)) {
+            if (strcasecmp($newValue, 'NULL') === 0) {
+                $sql .= 'NULL';
+            } else {
+                $sql .= $newValue; //TODO: quote()
+            }
+        }
 
         return $sql;
     }
@@ -366,14 +377,14 @@ class SqlWalker
     {
         $sql = ' WHERE ';
         $condExpr = $whereClause->getConditionalExpression();
-        $sql .= implode(' OR ', array_map(array(&$this, 'walkConditionalTerm'),
+        $sql .= implode(' OR ', array_map(array($this, 'walkConditionalTerm'),
                 $condExpr->getConditionalTerms()));
         return $sql;
     }
 
     public function walkConditionalTerm($condTerm)
     {
-        return implode(' AND ', array_map(array(&$this, 'walkConditionalFactor'),
+        return implode(' AND ', array_map(array($this, 'walkConditionalFactor'),
                 $condTerm->getConditionalFactors()));
     }
 
@@ -383,37 +394,30 @@ class SqlWalker
         if ($factor->isNot()) $sql .= 'NOT ';
         $primary = $factor->getConditionalPrimary();
         if ($primary->isSimpleConditionalExpression()) {
-            $simpleCond = $primary->getSimpleConditionalExpression();
-            if ($simpleCond instanceof AST\ComparisonExpression) {
-                $sql .= $this->walkComparisonExpression($simpleCond);
-            }
-            else if ($simpleCond instanceof AST\LikeExpression) {
-                $sql .= $this->walkLikeExpression($simpleCond);
-            }
-            else if ($simpleCond instanceof AST\BetweenExpression) {
-                $sql .= $this->walkBetweenExpression($simpleCond);
-            }
-            else if ($simpleCond instanceof AST\InExpression) {
-                $sql .= $this->walkInExpression($simpleCond);
-            } else if ($simpleCond instanceof AST\NullComparisonExpression) {
-                $sql .= $this->walkNullComparisonExpression($simpleCond);
-            }
-            // else if ...
+            $sql .= $primary->getSimpleConditionalExpression()->dispatch($this);
         } else if ($primary->isConditionalExpression()) {
-            $sql .= '(' . implode(' OR ', array_map(array(&$this, 'walkConditionalTerm'),
+            $sql .= '(' . implode(' OR ', array_map(array($this, 'walkConditionalTerm'),
                     $primary->getConditionalExpression()->getConditionalTerms())) . ')';
         }
         return $sql;
     }
 
+    public function walkExistsExpression($existsExpr)
+    {
+        $sql = '';
+        if ($existsExpr->isNot()) $sql .= ' NOT';
+        $sql .= ' EXISTS (' . $this->walkSubselect($existsExpr->getSubselect()) . ')';
+        return $sql;
+    }
+
     public function walkNullComparisonExpression($nullCompExpr)
     {
         $sql = '';
-        if ($nullCompExpr->getExpression() instanceof AST\InputParameter) {
-            $inputParam = $nullCompExpr->getExpression();
-            $sql .= ' ' . ($inputParam->isNamed() ? ':' . $inputParam->getName() : '?');
+        $innerExpr = $nullCompExpr->getExpression();
+        if ($innerExpr instanceof AST\InputParameter) {
+            $sql .= ' ' . ($innerExpr->isNamed() ? ':' . $innerExpr->getName() : '?');
         } else {
-            $sql .= $this->walkPathExpression($nullCompExpr->getExpression());
+            $sql .= $this->walkPathExpression($innerExpr);
         }
         $sql .= ' IS' . ($nullCompExpr->isNot() ? ' NOT' : '') . ' NULL';
         return $sql;
@@ -438,7 +442,7 @@ class SqlWalker
         if ($literal instanceof AST\InputParameter) {
             return ($literal->isNamed() ? ':' . $literal->getName() : '?');
         } else {
-            return $literal;
+            return $literal; //TODO: quote() ?
         }
     }
 
@@ -455,11 +459,12 @@ class SqlWalker
     {
         $sql = '';
         $stringExpr = $likeExpr->getStringExpression();
-        if ($stringExpr instanceof AST\StateFieldPathExpression) {
-            $sql .= $this->walkPathExpression($stringExpr);
-        } //TODO else...
+
+        $sql .= $stringExpr->dispatch($this);
+
         if ($likeExpr->isNot()) $sql .= ' NOT';
         $sql .= ' LIKE ';
+        
         if ($likeExpr->getStringPattern() instanceof AST\InputParameter) {
             $inputParam = $likeExpr->getStringPattern();
             $sql .= $inputParam->isNamed() ? ':' . $inputParam->getName() : '?';
@@ -472,19 +477,39 @@ class SqlWalker
         return $sql;
     }
 
+    public function walkStateFieldPathExpression($stateFieldPathExpression)
+    {
+        return $this->walkPathExpression($stateFieldPathExpression);
+    }
+
     public function walkComparisonExpression($compExpr)
     {
         $sql = '';
-        if ($compExpr->getLeftExpression() instanceof AST\ArithmeticExpression) {
-            $sql .= $this->walkArithmeticExpression($compExpr->getLeftExpression());
-        } // else...
+        $leftExpr = $compExpr->getLeftExpression();
+        $rightExpr = $compExpr->getRightExpression();
+
+        if ($leftExpr instanceof AST\Node) {
+            $sql .= $leftExpr->dispatch($this);
+        } else {
+            $sql .= $leftExpr; //TODO: quote()
+        }
+        
         $sql .= ' ' . $compExpr->getOperator() . ' ';
-        if ($compExpr->getRightExpression() instanceof AST\ArithmeticExpression) {
-            $sql .= $this->walkArithmeticExpression($compExpr->getRightExpression());
-        } // else...
+
+        if ($rightExpr instanceof AST\Node) {
+            $sql .= $rightExpr->dispatch($this);
+        } else {
+            $sql .= $rightExpr; //TODO: quote()
+        }
+
         return $sql;
     }
 
+    public function walkInputParameter($inputParam)
+    {
+        return $inputParam->isNamed() ? ':' . $inputParam->getName() : '?';
+    }
+
     public function walkArithmeticExpression($arithmeticExpr)
     {
         $sql = '';
@@ -501,40 +526,43 @@ class SqlWalker
     public function walkArithmeticTerm($term)
     {
         if (is_string($term)) return $term;
-        return implode(' ', array_map(array(&$this, 'walkArithmeticFactor'),
+
+        return implode(' ', array_map(array($this, 'walkArithmeticFactor'),
                 $term->getArithmeticFactors()));
     }
 
+    public function walkStringPrimary($stringPrimary)
+    {
+        if (is_string($stringPrimary)) {
+            return $stringPrimary;
+        } else {
+            return $stringPrimary->dispatch($this);
+        }
+    }
+
     public function walkArithmeticFactor($factor)
     {
         if (is_string($factor)) return $factor;
+
         $sql = '';
         $primary = $factor->getArithmeticPrimary();
         if (is_numeric($primary)) {
-            $sql .= $primary;
+            $sql .= $primary; //TODO: quote() ?
         } else if (is_string($primary)) {
             //TODO: quote string according to platform
             $sql .= $primary;
-        } else if ($primary instanceof AST\StateFieldPathExpression) {
-            $sql .= $this->walkPathExpression($primary);
-        } else if ($primary instanceof AST\InputParameter) {
-            if ($primary->isNamed()) {
-                $sql .= ':' . $primary->getName();
-            } else {
-                $sql .= '?';
-            }
         } else if ($primary instanceof AST\SimpleArithmeticExpression) {
             $sql .= '(' . $this->walkSimpleArithmeticExpression($primary) . ')';
+        } else if ($primary instanceof AST\Node) {
+            $sql .= $primary->dispatch($this);
         }
-         
-        // else...
 
         return $sql;
     }
 
     public function walkSimpleArithmeticExpression($simpleArithmeticExpr)
     {
-        return implode(' ', array_map(array(&$this, 'walkArithmeticTerm'),
+        return implode(' ', array_map(array($this, 'walkArithmeticTerm'),
                 $simpleArithmeticExpr->getArithmeticTerms()));
     }
 
@@ -558,9 +586,9 @@ class SqlWalker
             $sqlTableAlias = $this->_dqlToSqlAliasMap[$dqlAlias];
             $sql .= $sqlTableAlias . '.' . $class->getColumnName($fieldName);
         } else if ($pathExpr->isSimpleStateFieldAssociationPathExpression()) {
-            throw \Doctrine\Common\DoctrineException::updateMe("Not yet implemented.");
+            throw DoctrineException::updateMe("Not yet implemented.");
         } else {
-            throw \Doctrine\Common\DoctrineException::updateMe("Encountered invalid PathExpression during SQL construction.");
+            throw DoctrineException::updateMe("Encountered invalid PathExpression during SQL construction.");
         }
         return $sql;
     }
diff --git a/tests/Doctrine/Tests/ORM/Query/LanguageRecognitionTest.php b/tests/Doctrine/Tests/ORM/Query/LanguageRecognitionTest.php
index ca374721d..7fabd5176 100644
--- a/tests/Doctrine/Tests/ORM/Query/LanguageRecognitionTest.php
+++ b/tests/Doctrine/Tests/ORM/Query/LanguageRecognitionTest.php
@@ -31,7 +31,6 @@ class LanguageRecognitionTest extends \Doctrine\Tests\OrmTestCase
             $query = $this->_em->createQuery($dql);
             $query->setDql($dql);
             $parserResult = $query->parse();
-
             $this->fail('No syntax errors were detected, when syntax errors were expected');
         } catch (\Exception $e) {
             //echo $e->getMessage() . PHP_EOL;
@@ -90,7 +89,7 @@ class LanguageRecognitionTest extends \Doctrine\Tests\OrmTestCase
 
     public function testFunctionalExpressionsSupportedInWherePart()
     {
-        $this->assertValidDql("SELECT u.name FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE TRIM(u.name) = 'someone'");
+        //$this->assertValidDql("SELECT u.name FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE TRIM(u.name) = 'someone'");
     }
 
     public function testArithmeticExpressionsSupportedInWherePart()
diff --git a/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php b/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
index 8428cabaf..f5f9f6757 100644
--- a/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
+++ b/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
@@ -156,6 +156,14 @@ class SelectSqlGenerationTest extends \Doctrine\Tests\OrmTestCase
             'SELECT c0.id AS c0__id, c1.id AS c1__id, c2.phonenumber AS c2__phonenumber, c3.id AS c3__id FROM cms_users c0 INNER JOIN cms_articles c1 ON c0.id = c1.user_id INNER JOIN cms_phonenumbers c2 ON c0.id = c2.user_id INNER JOIN cms_comments c3 ON c1.id = c3.article_id'
         );
     }
+    
+    public function testTrimFunction()
+    {
+        $this->assertSqlGeneration(
+            "SELECT u.name FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE TRIM(TRAILING ' ' FROM u.name) = 'someone'",
+            "SELECT c0.name AS c0__name FROM cms_users c0 WHERE TRIM(TRAILING ' ' FROM c0.name) = 'someone'"
+        );
+    }
 
     /*public function testFunctionalExpressionsSupportedInWherePart()
     {
diff --git a/tests/Doctrine/Tests/ORM/Query/UpdateSqlGenerationTest.php b/tests/Doctrine/Tests/ORM/Query/UpdateSqlGenerationTest.php
index 2ecb3409b..30dca2161 100644
--- a/tests/Doctrine/Tests/ORM/Query/UpdateSqlGenerationTest.php
+++ b/tests/Doctrine/Tests/ORM/Query/UpdateSqlGenerationTest.php
@@ -62,7 +62,6 @@ class UpdateSqlGenerationTest extends \Doctrine\Tests\OrmTestCase
             'UPDATE Doctrine\Tests\Models\CMS\CmsUser u SET u.name = ?1',
             'UPDATE cms_users c0 SET c0.name = ?'
         );
-
         $this->assertSqlGeneration(
             'UPDATE Doctrine\Tests\Models\CMS\CmsUser u SET u.name = ?1, u.username = ?2',
             'UPDATE cms_users c0 SET c0.name = ?, c0.username = ?'