/ 
Symbol-Get-0.05
River stage one • 2 direct dependents • 2 total dependents
/ Symbol::Get

NAME

Symbol::Get - Read Perl’s symbol table programmatically

SYNOPSIS

package Foo;

our $name = 'haha';
our @list = ( 1, 2, 3 );
our %hash = ( foo => 1, bar => 2 );

use constant my_const => 'haha';

sub doit { ... }

my $name_sr = Symbol::Get::get('$Foo::name');    # \$name
my $list_ar = Symbol::Get::get('$Foo::list');    # \@list
my $hash_hr = Symbol::Get::get('$Foo::hash');    $ \%hash

#Defaults to __PACKAGE__ if none is given:
my $doit_cr = Symbol::Get::get('&doit');

#A constant--note the lack of sigil.
my $const_sr = Symbol::Get::get('Foo::my_const');

#The below return the same results since get_names() defaults
#to the current package if none is given.
my @names = Symbol::Get::get_names('Foo');      # keys %Foo::
my @names = Symbol::Get::get_names();

DESCRIPTION

Occasionally I have need to reference a variable programmatically. This module facilitates that by providing an easy, syntactic-sugar-y, read-only interface to the symbol table.

The SYNOPSIS above should pretty well cover usage.

ABOUT PERL CONSTANTS

This construction:

use constant foo => 'bar';

… does something rather special with the symbol table: while you access foo as though it were a function (e.g., foo(), or just bareword foo), the actual symbol table entry is a SCALAR reference, not a GLOB like other entries.

Symbol::Get::get() expects you to pass in names of constants WITHOUT trailing parens (()), as in the example above.

List constants are a bit more “interesting”. The following:

use constant things => qw( a b c );

… will, in Perl versions since 5.20, create an array reference in the symbol table, analogous to the scalar reference for a single value. Symbol::Get::get() will return a reference to that array.

PRE-5.20 NOTE: Perl versions prior to 5.20 stored list constants as code references. If you’re wanting to fetch a list constant in pre-5.20 code, you’ll need to fetch it as a coderef. An exception is thrown if you try to access a list constant without a sigil via Symbol::Get::get() in pre-5.20 Perl versions.

SEE ALSO

LICENSE

This module is licensed under the same license as Perl.