What happens when a ref is blessed into a non-existent class. Afterall bless's 2nd argument is a string and not a package qualifier.

bless [1,2,3] => 'nonexistent'

Some (irrelevant) info:

my use case is for "tagging" basic Perl data structures.

For example, a sub normally returns an arrayref. But in case of error it returns again an arrayref as: [code,errstr]. How can I differentiate the 2 cases? (Well the obvious way would be to create a proper Error class and return that in case of errors), but just for fun:

sub foo {
  if( $error ){
    return bless [0, "error was ..."] => 'YouveGotError'
  }
  return [42,43]
}
my $ret = foo();
die "@$ret" if ref($ret) eq 'YouveGotError';

[download]

Thanks LanX for looking this up on CB and Corion for pointing to %main:: (I was looking in %INC)

2' Edit: here is another use-case for distinguishing between scalar(ref)s

sub fortunecookie {
  my $cookie = ...;
  if( ! $cookie ){
    my $errstr = "failed to get a cookie because ...";
    return bless \$errstr => 'YouveGotError'
  }
  return \$cookie
}
# ok a bit awkward with the stringref but it demonstrates that one can
+ do this with scalars too

[download]

blw bli ako

In reply to Blessing with unknown classnames by bliako

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