1 files changed, 59 insertions, 0 deletions
diff --git a/vendor/doctrine/collections/lib/Doctrine/Common/Collections/Expr/ExpressionVisitor.php b/vendor/doctrine/collections/lib/Doctrine/Common/Collections/Expr/ExpressionVisitor.php
new file mode 100644
index 0000000..72bb153
--- /dev/null
+++ b/vendor/doctrine/collections/lib/Doctrine/Common/Collections/Expr/ExpressionVisitor.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Doctrine\Common\Collections\Expr;
+
+use RuntimeException;
+
+use function get_class;
+
+/**
+ * An Expression visitor walks a graph of expressions and turns them into a
+ * query for the underlying implementation.
+ */
+abstract class ExpressionVisitor
+{
+    /**
+     * Converts a comparison expression into the target query language output.
+     *
+     * @return mixed
+     */
+    abstract public function walkComparison(Comparison $comparison);
+
+    /**
+     * Converts a value expression into the target query language part.
+     *
+     * @return mixed
+     */
+    abstract public function walkValue(Value $value);
+
+    /**
+     * Converts a composite expression into the target query language output.
+     *
+     * @return mixed
+     */
+    abstract public function walkCompositeExpression(CompositeExpression $expr);
+
+    /**
+     * Dispatches walking an expression to the appropriate handler.
+     *
+     * @return mixed
+     *
+     * @throws RuntimeException
+     */
+    public function dispatch(Expression $expr)
+    {
+        switch (true) {
+            case $expr instanceof Comparison:
+                return $this->walkComparison($expr);
+
+            case $expr instanceof Value:
+                return $this->walkValue($expr);
+
+            case $expr instanceof CompositeExpression:
+                return $this->walkCompositeExpression($expr);
+
+            default:
+                throw new RuntimeException('Unknown Expression ' . get_class($expr));
+        }
+    }
+}