Name

lexicals - Get a hash of your current 'my' variables

Synopsis

use Template::Toolkit::Simple;
use lexicals;

sub mail {
  my $self = shift;
  my $name = 'Mr. ' . $self->get_name;
  my $address = $self->fetch_address($name);
  my $stamp = Postage::Stamp->new(0.44);
  my $envelope = tt->render('envelope', lexicals);
}

Description

Python has a builtin function called locals() that returns the lexically scoped variables in a name/value mapping. This is a very useful idiom. Instead of needing to create a hash like this:

my $hash = {
  foo => $foo,
  bar => $bar,
};

Just say:

my $hash = lexicals;

Assuming you have a $foo and $bar defined, you get the same thing.

The lexicals module exports a function called lexicals. This function returns the lexicals as a hash reference (in scalar or list context).

Arrays and Hashes

The above examples deal with lexical scalars. You can also get back lexical arrays and hashes. Note: since there is no sigil to tell scalars from arrays from hashes, you can't get back a scalar and an array or hash of the same name. In this case, SCALAR beats HASH beats ARRAY. Why? Because I said so! (Actually I just used the sort order of the sigils).

sub foo {
  my %h = ( O => 'HAI' );
  my @a = [ qw( foo bar baz ) ];
  my $s = 42;
  my %x = ( O => 'HAI' );
  my @x = [ qw( foo bar baz ) ];
  my $x = 42;
  print Dump lexicals;
}

would yield:

---
a:
- foo
- bar
- baz
h:
  O: HAI
s: 42
x: 42

Note

The lexicals function only reports the lexical variables variables that were defined before where it gets called.

Debugging Trick

This could be a handy idiom for debugging:

use XXX;

sub foo {
  ...
  XXX lexicals;     # See your lexicals in the nude.
  ...
}

See Also

• PadWalker

• Acme::Locals

• XXX

Author

Ingy döt Net <ingy@cpan.org>

Copyright and License

Copyright 2011-2015. Ingy döt Net.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See http://www.perl.com/perl/misc/Artistic.html