Some work on parser, not used yet.

core/SqlParser.h

@@ -2,6 +2,7 @@
 #define SQLPARSER_H
 
 #include "SqlLexer.h"
+#include "SqlAstNode.h"
 #include <memory>
 #include <optional>
 
@@ -22,6 +23,7 @@ enum class Keyword {
 
 namespace SqlAst {
 
+	class Node;
 	class Select;
 	class SelectList;
 
@@ -37,7 +39,7 @@ class SqlParser
 public:
 	explicit SqlParser(SqlLexer &lexer);
 
-	void parse();
+	std::shared_ptr<SqlAst::Node> parse();
 
 	/** Checks to see if the next token is the expected keyword.
 	 *