Problème en lex et yacc

%{
#include <stdio.h>
#include "yab.h"
%}
%%
[0-9]+                  NUMBER;
heat                    TOKHEAT;
on|off                  STATE;
target                  TOKTARGET;
temperature             TOKTEMPERATURE;
\n                      ;
[ \t]+                  ;


%%

%{
#include <stdio.h>
#include <string.h>
%}

%token NUMBER TOKHEAT STATE TOKTARGET TOKTEMPERATURE

%%

commands:
        | commands command
        ;

command:
        heat_switch
        |
        target_set
        ;

heat_switch:
        TOKHEAT STATE
        {
                printf("\tHeat turned on or off\n");
        }
        ;

target_set:
        TOKTARGET TOKTEMPERATURE NUMBER
        {
                printf("\tTemperature set\n");
        }
        ;
%%

int yyerror(const char *str)
{
        fprintf(stderr,"error: %s\n",str);
}
 
int yywrap()
{
        return 1;
} 
  
main()
{
        yyparse();
} 

 lex example4.l
yacc example4.y
cc lex.yy.c y.tab.c -o example4 

example4.l: Dans la fonction «yylex» :
example4.l:6: erreur: «NUMBER» undeclared (first use in this function)
example4.l:6: erreur: (Each undeclared identifier is reported only once
example4.l:6: erreur: for each function it appears in.)
example4.l:7: erreur: «TOKHEAT» undeclared (first use in this function)
example4.l:8: erreur: «STATE» undeclared (first use in this function)
example4.l:9: erreur: «TOKTARGET» undeclared (first use in this function)
example4.l:10: erreur: «TOKTEMPERATURE» undeclared (first use in this function)