http://www.perlmonks.org?node_id=1057148


in reply to shift implicit dereference

if you don't really need references use aliasing !

DB<122> $a => 5 DB<123> sub alias_add { $_[0]+=2 } DB<124> alias_add $a => 7 DB<125> $a => 7

But to fully answer the original question:

DB<126> sub ref_add { ${ shift() }+=2 } DB<127> ref_add \$a => 9 DB<128> $a => 9 DB<129> sub ref_add2 { ${ +shift }+=2 } DB<130> ref_add \$a => 11 DB<131> $a => 11

update

or using parens

DB<102> $a=11 => 11 DB<103> sub ref_add3 { ${ (shift) }+=2 } DB<104> ref_add3 \$a; $a => 13

Cheers Rolf

( addicted to the Perl Programming Language)

1) from perlsub:

Any arguments passed in show up in the array @_. Therefore, if + you called a function with two arguments, those would be stored in +$_[0] and $_[1]. The array @_ is a local array, but its elements are + aliases for the actual scalar parameters. In particular, if an element + $_[0] is updated, the corresponding argument is updated (or an error +occurs if it is not updatable).