mirror of
https://git.FreeBSD.org/ports.git
synced 2024-12-12 03:00:28 +00:00
2a52f8d735
Starting with Perl 5.10, it is possible to create a lexical version of the Perl
default variable $_. Certain Perl constructs like the given keyword
automatically use a lexical $_ rather than the global $_.
It is occasionallly useful for a sub to be able to access its caller's $_
variable regardless of whether it was lexical or not. The (_) sub prototype is
the official way to do so, however there are sometimes disadvantages to this; in
particular it can only appear as the final required argument in a prototype, and
there is no way of the sub differentiating between an explicitly passed argument
and $_.
The lexical::underscore function returns a scalar reference to either a lexical
$_ variable somewhere up the call stack (using PadWalker magic), or to the
global $_ if there was no lexical version.
Wrapping lexical::underscore in ${ ... } dereferences the scalar reference,
allowing you to access (and even assign to) it.
WWW: http://search.cpan.org/dist/lexical-underscore/
20 lines
989 B
Plaintext
20 lines
989 B
Plaintext
Starting with Perl 5.10, it is possible to create a lexical version of the Perl
|
|
default variable $_. Certain Perl constructs like the given keyword
|
|
automatically use a lexical $_ rather than the global $_.
|
|
|
|
It is occasionallly useful for a sub to be able to access its caller's $_
|
|
variable regardless of whether it was lexical or not. The (_) sub prototype is
|
|
the official way to do so, however there are sometimes disadvantages to this; in
|
|
particular it can only appear as the final required argument in a prototype, and
|
|
there is no way of the sub differentiating between an explicitly passed argument
|
|
and $_.
|
|
|
|
The lexical::underscore function returns a scalar reference to either a lexical
|
|
$_ variable somewhere up the call stack (using PadWalker magic), or to the
|
|
global $_ if there was no lexical version.
|
|
|
|
Wrapping lexical::underscore in ${ ... } dereferences the scalar reference,
|
|
allowing you to access (and even assign to) it.
|
|
|
|
WWW: http://search.cpan.org/dist/lexical-underscore/
|