(*
 * This is a version of ../inputs//term-factor-does-work.rsl with the latest
 * and greates grammar-like syntax.
 *)

module TermFactorAttributeGrammar;

    (*
     * Attribute definitions.
     *)
    define obj attribute type:Type;
    define obj attribute valu:Value;
    define obj attribute text:string;

    (*
     * Attribute type definitions.
     *)
    obj Type =  string;
    obj Value =  number;
    obj Symtab =  SymtabEntry*;
    obj SymtabEntry =  n:Name and t:Type and v:Value;
    obj Name =  string;

    (*
     * Auxiliary functions.
     *)
    function Lookup(Symtab, Name)->SymtabEntry;

    (*
     * Global attributes.
     *)
    var symtab:Symtab;

    (*
     * Grammar and semantic action definitions.
     *)

    rule E	=	e:E "+" t:T
		    {this.:type = (if e.:type = t.:type
                                    then e.:type else "ERROR");
				    this.:valu = e.:valu + t.:valu}
        |
		t:T
		    {this.:type = t.:type;
                     this.:valu = t.:valu;}
	;

    rule T	=	t:T "*" f:F
		    {this.:type = (if e.:type = t.:type
                                    then e.:type else "ERROR");
				    this.:valu = e.:valu * t.:valu;}
	|
		f:F
		    {this.:type = f.:type;
                     this.:valu = f.:valu;}
	;

    rule F	=	x:"x"
	            {this.:type = Lookup(symtab, x.:text).t;
                     this.:valu = Lookup(symtab, x.:text).v;}
	;

end TermFactorAttributeGrammar;