%{
    #define COLORS

    #include <stdio.h>
    #include "extio.h"
    extern int yylineno;

    int yyerror(char*);
    int yylex();
%}

%union {
    char *str;
    int num;
}

%token Variable
%token Integer
%token <str> Ident
%token <num> Number
%token Operator

%%
program:    decllist exprlist;

decllist:   decl ';'
            | decllist decl ';'
            | /* empty */ |
            error ';' { notify(ERROR, "in declaration"); };

decl:       Variable idlist ':' type { notify(DEBUG, "declaration found"); };

idlist:     Ident { notify(DEBUG, "identifier found"); };
            | idlist ',' Ident;

type:       Integer { notify(DEBUG, "type found"); };

exprlist:   expr ';' { notify(DEBUG, "expression discovered"); }
            | exprlist expr ';';

expr:       '(' expr Operator expr ')'
            | error expr Operator expr ')'  { notify(ERROR, "missing open parenthesis"); }
            | '(' error Operator expr ')'   { notify(ERROR, "error in left hand expression"); }
            | '(' expr error expr ')'       { notify(ERROR, "expected operator in expression"); }
            | '(' expr Operator error ')'   { notify(ERROR, "error in right hand expression"); }
            | '(' expr Operator expr error  { notify(ERROR, "missing closing parenthesis"); }
            | Ident { notify(DEBUG, "identifier: %s", $1); }
            | Number { notify(DEBUG, "number: %08x", yyval.num); }
            | error ';' { notify(ERROR, "in expression"); };
%%

int main() {
    printf("Bitte geben Sie ein Program ein: \n");
    yyparse();
    return 0;
}

int yyerror(char *s) {
    return 0;
}