--- /dev/null
+<?php
+/*
+ * 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 MIT license. For more information, see
+ * <http://www.doctrine-project.org>.
+ */
+
+namespace Doctrine\ORM\Query;
+
+/**
+ * A parse tree printer for Doctrine Query Language parser.
+ *
+ * @author Janne Vanhala <jpvanhal@cc.hut.fi>
+ * @license http://www.opensource.org/licenses/lgpl-license.php LGPL
+ * @link http://www.phpdoctrine.org
+ * @since 2.0
+ */
+class Printer
+{
+ /**
+ * Current indentation level
+ *
+ * @var int
+ */
+ protected $_indent = 0;
+
+ /**
+ * Defines whether parse tree is printed (default, false) or not (true).
+ *
+ * @var bool
+ */
+ protected $_silent;
+
+ /**
+ * Constructs a new parse tree printer.
+ *
+ * @param bool $silent Parse tree will not be printed if true.
+ */
+ public function __construct($silent = false)
+ {
+ $this->_silent = $silent;
+ }
+
+ /**
+ * Prints an opening parenthesis followed by production name and increases
+ * indentation level by one.
+ *
+ * This method is called before executing a production.
+ *
+ * @param string $name production name
+ */
+ public function startProduction($name)
+ {
+ $this->println('(' . $name);
+ $this->_indent++;
+ }
+
+ /**
+ * Decreases indentation level by one and prints a closing parenthesis.
+ *
+ * This method is called after executing a production.
+ */
+ public function endProduction()
+ {
+ $this->_indent--;
+ $this->println(')');
+ }
+
+ /**
+ * Prints text indented with spaces depending on current indentation level.
+ *
+ * @param string $str text
+ */
+ public function println($str)
+ {
+ if ( ! $this->_silent) {
+ echo str_repeat(' ', $this->_indent), $str, "\n";
+ }
+ }
+}