lxm.pl0

对PL0原编译器进行了以下的扩充：1.增加以下保留字else(elsesym), for(forsym),to(tosym),downto(downtosym),return(returnsym),[

var x,y;
procddure p;
var a;
procedure q;
var b;
begin(*q*)
b:=10;
end(*q*);
procedure s;
var c,d;
procedure r;
var e,f;
begin (*r*)
call q;
end(*r*);
begin(*s*)
call r;
end (*s*);
begin(*p*)
call s;
end(*p*);
begin(*main*)
call p;
end(*main*).