The following is a function with some code so it can be used if neccessary:

use Term::ReadKey;
sub masked_read(;\$$) {

  my $mask;

  if($_[1]){
    if(length $_[1] > 1){
      die "arg 2 of masked_read() should only be 1 character long";
      }
    $mask = $_[1];
    }
  else{
    $mask="*";
    }

  my $key;
  $|=1;
  while(1) {
      while(not defined($key = ReadKey(-1))) {};
      if(ord($key) != 13) {
         if(ord($key) == 8) {
            print "\b \b";
            chop(${$_[0]});
            }
         else {
            ${$_[0]} .= $key;
            print "$mask";
            }
         }
      else {last}
      }
  $|=0;
  return ${$_[0]};
  }
print "Enter:";
my $password = masked_read;
print "\npassword:$password";
[download]

The first Question:

Currently, when called two arguments are passed. The function can be called in any of the following ways:

masked_read($password, $mask);
masked_read($password, '#');
masked_read($password);
my $password = masked_read();
[download]

However, I would like the user to also have the following option: $password = masked_read('#')

I have already considered simply switching the order of the two parameters; however, that leads to syntax such as: masked_read('#',$password) . Which is counterintuitive and creates the problem of getting the scalar variable when the first value is not present.

I have also thought of creating a if-then structure to determine what the user has passed, but cannot think of or find a way to determine whether something is a variable or not.

This issue is the one that has stumped me, and any direction at all would be helpful.
Second Question:

As you can see I am currently using the length function to catch arguments in $_[1] that is more than one character. Right now this is needed because the method I use to mask the password on the screen does not work with a mask of more than one character if the person enters a backspace. This works fine, however I was wondering if there was a more efficient way of doing this. I looked through most of the information I have on prototyping and I did not see any way to accomplish it through prototyping means. If anyone knows of an alternative, it would be very helpful.


I realize this subroutine is pretty trite however I am doing this mostly as a means to learn about prototyping, subroutines, and later, making modules.