Re: $arrayref.ref?

[Larry Wall]

On Sat, Jul 30, 2005 at 02:14:52PM +0200, Ingo Blechschmidt wrote:
: Hi,
: 
: http://use.perl.org/~autrijus/journal/25337:
: > deref is now 0-level; $x = 3; $y = \$x; $y++. # now an exception
: 
:     my $arrayref = [1,2,3];
: 
:     say $arrayref.ref;            # Ref or Array?

Array.

:     say $arrayref.isa("Ref");     # true or false?

False, though tied($arrayref).isa("Ref") is probably true.

:     say $arrayref.isa("Array");   # false or true?

True.

:     say +$arrayref;               # 3 or error?
:     say $arrayref + 1;            # 4 or error?

Both work.

To the first approximation, refs to scalar "non-object" values must be
explicitly derefed.  But refs to non-scalar containers are considered
objects so they will happily autoderef one level.  It's possible we
may find a way to relax the former constraint, but if so, it would
go back to one-level deref, not all levels.

Larry