Hello kcott!

Interesting to hear about your experience teaching students. I am sure the style you introduced might indeed help improve the situation you described. But once you have declared a variable with a prefix, it is no longer optional to remove the prefix. This is why I don't like the idea of a prefix that is part of the variable name. A prefix as a part of the sigil would seem like a better idea. Then it could be made optional.

For example, consider a function called with three references. A scalar reference, a hash reference, and a string reference;

sub func {
   my ( $rs_str, $hr_desktop_info, $ha_files ) = @_; 

  $$rs_string = update_string_ref();
  for ( keys %$hr_desktop_info ) {
     ...
     push @$ha_files, $file;
  }
  ....

}
[download]

I seems to me like the prefixes will introduce too much noise in the source code. In this case, it might be better if only the first line in the function documented the type of the reference, and then subsequent lines could omit the variable name prefix:

sub func {
   my ( $rs_str, $hr_desktop_info, $ha_files ) = @_; 

  $$str = update_string_ref();
  for ( keys %$desktop_info ) {
     ...
     push @$files, $file;
  }
  ....

}
[download]

Of course, the above code is not yet possible. And further it could not easily be made part of Perl in the future. But maybe a new type of prefix could be used, for example $>$, $>%, and $>@ ?

sub func {
   my ( $>$str, $>%desktop_info, $>@files ) = @_; 

  ....

}
[download]

On the other hand, I can see the clash here with the Perl special variable $> (The effective uid of this process). So this syntax might be difficult to implement.

Regarding the last point of your reply. Yes, I agree that if I call func( $var->@* ), the function will indeed receive @$var. But I assumed a function definition on the form

sub func {
  my ( $var ) = @_;
 
  ...

}
[download]

Now, the function would "receive" $var->[0] ( in the sense that $var in the function will be equal $var->[0] of the caller). But I think this (minor) issue of whether the function receives the whole array or only its first item is just a distraction from the main topic of the discussion. So I will not go further into the issue.