summaryrefslogtreecommitdiff
path: root/lib/Env.pm
blob: 21870903b4b5b0246d57384bf45caa744e0a4b29 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
package Env;

=head1 NAME

Env - Perl module that imports environment variables

=head1 DESCRIPTION

Perl maintains environment variables in a pseudo-associative-array
named %ENV.  For when this access method is inconvenient, the Perl
module C<Env> allows environment variables to be treated as simple
variables.

The Env::import() function ties environment variables with suitable
names to global Perl variables with the same names.  By default it
does so with all existing environment variables (C<keys %ENV>).  If
the import function receives arguments, it takes them to be a list of
environment variables to tie; it's okay if they don't yet exist.

After an environment variable is tied, merely use it like a normal variable.
You may access its value 

    @path = split(/:/, $PATH);

or modify it

    $PATH .= ":.";

however you'd like.
To remove a tied environment variable from
the environment, assign it the undefined value

    undef $PATH;

=head1 AUTHOR

Chip Salzenberg <chip@fin.uucp>

=cut

sub import {
    my ($callpack) = caller(0);
    my $pack = shift;
    my @vars = @_ ? @_ : keys(%ENV);

    foreach (@vars) {
	tie ${"${callpack}::$_"}, Env, $_ if /^[A-Za-z_]\w*$/;
    }
}

sub TIESCALAR {
    bless \($_[1]);
}

sub FETCH {
    my ($self) = @_;
    $ENV{$$self};
}

sub STORE {
    my ($self, $value) = @_;
    if (defined($value)) {
	$ENV{$$self} = $value;
    } else {
	delete $ENV{$$self};
    }
}

1;