%{
    #include <stdio.h>
    extern int yylex(void);
    extern void yyerror(const char*);
%}

%token LEFTBRACE RIGHTBRACE MAP AREA CORNER NORTH EAST SOUTH WEST NAME COORDINATE
%define parse.error verbose
%start input

%%

input : MAP NAME LEFTBRACE areas RIGHTBRACE ;

areas : areas area | area ;

area : AREA NAME LEFTBRACE corners RIGHTBRACE ;

corners : corners corner | corner ;

corner : CORNER COORDINATE direction COORDINATE direction ;

direction : NORTH | EAST | SOUTH | WEST ;

%%

int main(void) {
    printf("Write a complete input, ending with EOF:\n");
    yyparse();
    printf("Ok!\n");
    return 0;
}

void yyerror(const char *s) {
    printf("Incorrect input! Error message: %s\n", s);
}

int yywrap(void) {
    return 1;
}