Beefy Boxes and Bandwidth Generously Provided by pair Networks
Syntactic Confectionery Delight

Re^5: Perl bug ?

by choroba (Bishop)
on Feb 06, 2013 at 12:35 UTC ( #1017407=note: print w/replies, xml ) Need Help??

in reply to Re^4: Perl bug ?
in thread Perl bug ?

Hmmm... strange. Can be simplified to
perl -E 'my $e; say for $e && 0, $e->[0];'
لսႽ ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

Replies are listed 'Best First'.
Re^6: Perl bug ?
by tinita (Parson) on Feb 06, 2013 at 13:20 UTC
    seems like the arguments for "for" are executed first and then the loop body. so:
    the first element is $e && 0 which evaluates to $e. then the second argument is processed, autovivify happens.
    when in the loop body, $e is an array reference already, and because the first element is an alias to $e it prints ARRAY(0xde0d48). seems logical to me.

      Yes. B::Deparse shows the same interpretation:

      Q:\>perl -MO=Deparse -E "my $e; say for $e && 0, $e->[0];" BEGIN { $^H{'feature_unicode'} = q(1); $^H{'feature_say'} = q(1); $^H{'feature_state'} = q(1); $^H{'feature_switch'} = q(1); } my $e; ; say $_ foreach ($e && 0, $$e[0]); -e syntax OK

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1017407]
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others making s'mores by the fire in the courtyard of the Monastery: (5)
As of 2018-02-22 05:20 GMT
Find Nodes?
    Voting Booth?
    When it is dark outside I am happiest to see ...

    Results (288 votes). Check out past polls.