Re^2: overload conflict between * and *= (as an example)

yeah, this took care of it, thanks. I had read that part of the perldoc before, but I could not imagine how this could be relevant, but looking at the section again, lit the light for me;-)
And any suggestion as to why the rather inconspicious and innocent $test->{obj} = $N; can screw up the entire short program? I guessed that, if Perl would consider the "=" overloaded, it had to work only on lvalues, but the offending $N here is a rvalue, so, why does this produce a reaction at all?

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Re^3: overload conflict between * and *= (as an example) by tobyink (Canon) on Feb 27, 2012 at 18:13 UTC
The reason is that with numbers you can do this: `my $a = 1; my $b = $a; $a++; $b++; say $a; # says "2" say $b; # says "2"` [download] But if $a and $b are overloaded references to numbers, then they refer to the same object, so you've actually incremented the same object twice. $a and $b are both 3. Perl forces you to deal with (or at least acknowledge that you've thought about) this problem by in certain circumstances forcing you to provide an overload for "=".	[reply] [d/l]

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Re^3: overload conflict between * and *= (as an example)
by tobyink (Canon) on Feb 27, 2012 at 18:13 UTC

The reason is that with numbers you can do this:

my $a = 1;
my $b = $a;
$a++;
$b++;
say $a; # says "2"
say $b; # says "2"
[download]

But if $a and $b are overloaded references to numbers, then they refer to the same object, so you've actually incremented the same object twice. $a and $b are both 3.

Perl forces you to deal with (or at least acknowledge that you've thought about) this problem by in certain circumstances forcing you to provide an overload for "=".

[reply]
[d/l]