John W. Krahn wrote: > Steve Bertrand wrote: >> What I want to know, is if someone could place parens to help me better >> understand the precedence order in the last two lines. I know they are >> legal as they do work, but I don't know how the interpreter is >> interpreting them:
>> $user_ref->{$username}{payment} += $payment ||= $payment;
>> $user_ref->{$username}{amount} += $amount ||= $amount;
> Assignments happen right-to-left so, for instance, this will work:
>
> my $x = my $y = my $z = some_value();
>
> where $z will be assigned to first and then $y will be assigned the
> result of the first assigment and $x will be assigned the result of the
> second assignment.
>
> $ perl -MO=Deparse,-p -e'my $x = my $y = my $z = some_value();'
> (my $x = (my $y = (my $z = some_value())));
> -e syntax OK
Ahh. Not only did you make it understandable verbally, but also rendered
it in a way that I (and others) could yank/put it in order to find out
the parenthesis of my own code for myself!:
% perl -MO=Deparse,-p -e \
'my $user_ref->{$username}{amount} += $amount ||= $amount;'
($my $user_ref{$username}{'amount'} += ($amount ||= $amount));
-e syntax OK
Nice! Perl just tells me... after I've been informed :)
Thanks John!
Steve
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