diff --git a/amend/lexer.h b/amend/lexer.h
new file mode 100644
index 0000000..fc716fd
--- /dev/null
+++ b/amend/lexer.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef AMEND_LEXER_H_
+#define AMEND_LEXER_H_
+
+#define AMEND_LEXER_BUFFER_INPUT 1
+
+void yyerror(const char *msg);
+int yylex(void);
+
+#if AMEND_LEXER_BUFFER_INPUT
+void setLexerInputBuffer(const char *buf, size_t buflen);
+#else
+#include <stdio.h>
+void yyset_in(FILE *in_str);
+#endif
+
+const char *tokenToString(int token);
+
+typedef enum {
+    AM_UNKNOWN_ARGS,
+    AM_WORD_ARGS,
+    AM_BOOLEAN_ARGS,
+} AmArgumentType;
+
+void setLexerArgumentType(AmArgumentType type);
+int getLexerLineNumber(void);
+
+#endif  // AMEND_LEXER_H_