Start of new ANTLR4 based parser.

Very simple tests pass.

pglablib/sqlast/StatementList.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "Node.h"
+
+#include <memory>
+#include <vector>
+
+namespace sqlast {
+
+    class Statement;
+
+    class StatementList: public Node
+    {
+    public:
+        StatementList();
+
+        void Add(std::unique_ptr<Statement> &&statement);
+        Statement &Get(int index);
+        int Count() const;
+
+    private:
+        using Statements = std::vector<std::unique_ptr<Statement>>;
+
+        Statements statements;
+    };
+
+}