Simple yacc grammars give an error
yacc
Solution
Its a warning, not an error, so you should be fine if you ignore it. But if you really want to get rid of the warning, you could add
%{
int yylex();
%}
to the top of your `.y` file
Problem
I have a question for yacc compiler. I do not compile simple yacc grammar. Here is the code section : ``` /*anbn_0.y */ %token A B %% start: anbn '\n' {printf(" is in anbn_0\n"); return 0;} anbn: empty | A anbn B ; empty: ; %% #include "lex.yy.c" yyerror(s) char *s; { printf("%s, it is not in anbn_0\n", s); ``` I use mac os x and, i try yo command; `$ yacc anbn_0.y` and then `$ gcc -o anbn_0 y.tab.c -ll` and give me error. Here is the error ; ``` warning: implicit declaration of function 'yylex' is invalid in C99 [-Wimplicit-function-declaration] yychar = YYLEX; ``` Why do I get an error ?