Re: bad code to good golf

* shmem <[email protected]> [2007-12-10 12:55]:
> Well, if we were to return an array reference instead of a hash
> ref,
> 
> sub new{bless\@_,shift}
> 
> works. Why does the shift get executed before an array
> reference is constructed - but not if a hashref is constructed
> - from an array?

It probably doesn’t. Either way, evaluation order is a red
herring: your construction will work regardless of which
subexpression is evaluated first!

You managed to confuse yourself. Congratulations. :-)  (Or you
are underhandedly trying to confuse us. In that case, sorry bub,
better luck next time. :-) )

What happens is that `\` takes a *reference* to the array. And
of course when you do that, any modifications of the referent,
including *subsequent* modifications, will be seen by anyone who
holds a reference to it.

In contrast, the hash constructors make a *copy* of the array,
and that copy will not be affected but subsequent modifications
to the source array.

Anyone who has trouble following should consider the difference
between the following two:

    sub new { bless \@_, shift }
    # vs
    sub new { bless [@_], shift }

Consider how many arrays are involved in either case, and which
one is affected by the `shift`.

-- 
*AUTOLOAD=*_;sub _{s/(.*)::(.*)/print$2,(",$\/"," ")[defined wantarray]/e;$1}
&Just->another->Perl->hack;
#Aristotle Pagaltzis // <http://plasmasturm.org/>