add antlr

lib/antlr4/include/atn/EmptyPredictionContext.h

@@ -0,0 +1,27 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/SingletonPredictionContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC EmptyPredictionContext : public SingletonPredictionContext {
+  public:
+    EmptyPredictionContext();
+
+    virtual bool isEmpty() const override;
+    virtual size_t size() const override;
+    virtual Ref<PredictionContext> getParent(size_t index) const override;
+    virtual size_t getReturnState(size_t index) const override;
+    virtual std::string toString() const override;
+
+    virtual bool operator == (const PredictionContext &o) const override;
+  };
+
+} // namespace atn
+} // namespace antlr4