78 lines
1.6 KiB
Perl
78 lines
1.6 KiB
Perl
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package Env;
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=head1 NAME
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Env - perl module that imports environment variables
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=head1 SYNOPSIS
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use Env;
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use Env qw(PATH HOME TERM);
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=head1 DESCRIPTION
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Perl maintains environment variables in a pseudo-hash named %ENV. For
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when this access method is inconvenient, the Perl module C<Env> allows
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environment variables to be treated as simple variables.
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The Env::import() function ties environment variables with suitable
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names to global Perl variables with the same names. By default it
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does so with all existing environment variables (C<keys %ENV>). If
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the import function receives arguments, it takes them to be a list of
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environment variables to tie; it's okay if they don't yet exist.
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After an environment variable is tied, merely use it like a normal variable.
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You may access its value
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@path = split(/:/, $PATH);
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or modify it
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$PATH .= ":.";
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however you'd like.
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To remove a tied environment variable from
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the environment, assign it the undefined value
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undef $PATH;
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=head1 AUTHOR
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Chip Salzenberg E<lt>F<chip@fin.uucp>E<gt>
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=cut
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sub import {
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my ($callpack) = caller(0);
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my $pack = shift;
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my @vars = grep /^[A-Za-z_]\w*$/, (@_ ? @_ : keys(%ENV));
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return unless @vars;
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eval "package $callpack; use vars qw("
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. join(' ', map { '$'.$_ } @vars) . ")";
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die $@ if $@;
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foreach (@vars) {
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tie ${"${callpack}::$_"}, Env, $_;
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}
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}
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sub TIESCALAR {
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bless \($_[1]);
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}
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sub FETCH {
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my ($self) = @_;
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$ENV{$$self};
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}
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sub STORE {
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my ($self, $value) = @_;
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if (defined($value)) {
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$ENV{$$self} = $value;
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} else {
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delete $ENV{$$self};
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}
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}
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1;
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