Imagine you have a reference to a subroutine that may return a reference to a list, or a reference to a hash, or a list, or a hash.

If we were only getting references back, life would be good : 

sub determineType 
{
   $sub_ref = shift;
   $rval = $sub_ref(@_);
   return @$rval if( ref($rval) eq 'ARRAY' );
   return %$rval if( ref($rval) eq 'HASH' );
}

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What I need is some analog for non-reference return values. For instace, if the subroutine returns a list I don't want to evaluate it in scalar context and end up with the length.

Can I only reflect on references and not on base types?

Is there some way I can cast the return value of the subroutine to a reference on the fly; so that I may inspect it?

UPDATE

Thanks to all those who responded. Particularly phaylon, friedo, and ikegami. As I stated below, I'm basiclly trying to pass through the return value of the subroutine reference. Here is the "final" proof of concept. 
sub execSubroutine
{
    my $sub = shift;
    my @sub_ret = &{$sub}(@_);

    # Return an list if we get a list with more than one value
    # this will satisfy callers expecting lists and/or hashes
    return @sub_ret if (@sub_ret > 1);

    my $rval = $sub_ret[0];

    # If we have a ref de-reference and return.
    if (my $type = ref($rval)) {
        return @$rval if ($type eq 'ARRAY');
        return %$rval if ($type eq 'HASH');
    }

    # If not a ref and the caller wants a list, give it to them
    if (wantarray) {
        return @sub_ret;
    }

    # Otherwise return a scalar
    return $rval;
}

[download]
If you are interested in seeing the code I used to test this routine, drop me a line and I'll add it.

In reply to Determining subroutine return type by satchm0h

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