Re^2: question 1st - undefined behaviour (perlop)

[rumos2]

I've mean exactly this -
my $x=5;
my $y=$x + ++$x;
$y returns 12.

here $x in first position is used as original $x and it's returns it's changed value after calculation of pre-increment.

my $x=5;
my $y=$x + ++$x + $x++
$y returns 18. precedence crash(5($x) + 7(++$x is 6, but returns $x and become 7 after next step) + 6($x++, at now $x is 7, but here we get copy before increment and get 6) in this order) or $x is used as a copy at here (like after $x++) and this copy is maked BEFORE any changes.
my $x=5;
my $y=++$x + $x++ + $x
$y returns 20 -
++$x return $x and make it's value 6; $x++ return 6 forever, but $x is 7 at now
7 + 6 + 7 == 20 - ok.

[Anonymous Monk]

What perl version? Have you tried 5.6,5.8,5.10,5.12,5.14,5.16,5.18? :)

I don't understand what you're after (i'm tired) but maybe you can find some winsdom at the following


Pre vs Post Incrementing variables
Prefix and postfix increment/decrement operator query
Pre-increment *and* Post-increment
Auto Increment "magic" Inquiry
Re^3: $1 not "freezing" in an addition
Quantum Weirdness and the Increment Operator

The Universe of Discourse: Undefined behavior in Perl and other languages
Order of operations, mutators, aliasing and whammies
order of operations with conditionals at the end
Perl::Critic::Policy::ValuesAndExpressions::UndefinedBehaviourMaybeQuoteit / $1 not quoted (value not frozen) undefined behaviour

[Anonymous Monk]

Re^5: Order of execution of functions in list ( \(shift @_ ) reference to alias \$_[0] references original )
shift->SUPER::new(@_) is shift(@_)->SUPER::new(@_)