makePrintable method
Implementation
String makePrintable(String s) {
final result = StringBuffer();
for (int i = 0; i < s.length; i++) {
if (s.codeUnitAt(i) < 32 || s.codeUnitAt(i) > 126) {
result.write('.');
} else {
result.writeCharCode(s.codeUnitAt(i));
}
}
return result.toString();
}