printf ::= #foreign("printf","libc.so.6") fn(#C &"const char", #C ..) #C int; // NOTE: this doesn't work (e.g. "%%%") tprintf_valid ::= fn(fmt :: []char, nargs: int) bool { if fmt[fmt.len-1] != '\0' { return false; } count := 0; for x, i := fmt { if x == '%' { if i == fmt.len-1 { count += 1; } elif fmt[i+1] != '%' { count += 1; } else { count -= 1; } } } count == nargs }; tprintf ::= fn(fmt :: []char, args: ..) { #if !tprintf_valid(fmt, args.len) { #error "Invalid printf format"; } f := fmt; printf(&f[0], args); }; main ::= fn() { tprintf("%d %d%%\n\0", 3, 4); tprintf("%d %d %d%%\n\0", 3, 4, 5); tprintf("Hello!\n\0"); };