--- ./parser.h.xiugai	2021-08-03 20:48:31.260494920 +0800
+++ ./parser.h	2021-08-03 20:48:45.900664125 +0800
@@ -30,4 +30,4 @@

 int yylex();
 int yyerror(obj_t **root, char *s);
-FILE *yyin;
+extern FILE *yyin;