es */
precedence left PLUS, MINUS;
precedence left TIMES, DIVIDE, MOD;
precedence left UMINUS;

/* The grammar */
expr_list ::= expr_list expr_part | 
              expr_part;
expr_part ::= expr SEMI;
expr      ::= expr PLUS expr 
            | expr MINUS expr  
            | expr TIMES expr  
            | expr DIVIDE expr  
            | expr MOD expr 
	    | MINUS expr %prec UMINUS
            | LPAREN expr RPAREN
	    | NUMBER
	    ;
</tt></pre>
<hr><br>
We will consider each part of the specification s