=head1 NAME
-Env - perl module that imports environment variables
+Env - perl module that imports environment variables as scalars or arrays
=head1 SYNOPSIS
use Env;
use Env qw(PATH HOME TERM);
+ use Env qw($SHELL @LD_LIBRARY_PATH);
=head1 DESCRIPTION
-Perl maintains environment variables in a pseudo-hash named %ENV. For
+Perl maintains environment variables in a special hash named C<%ENV>. For
when this access method is inconvenient, the Perl module C<Env> allows
-environment variables to be treated as simple variables.
+environment variables to be treated as scalar or array variables.
-The Env::import() function ties environment variables with suitable
+The C<Env::import()> function ties environment variables with suitable
names to global Perl variables with the same names. By default it
-does so with all existing environment variables (C<keys %ENV>). If
-the import function receives arguments, it takes them to be a list of
-environment variables to tie; it's okay if they don't yet exist.
+ties all existing environment variables (C<keys %ENV>) to scalars. If
+the C<import> function receives arguments, it takes them to be a list of
+variables to tie; it's okay if they don't yet exist. The scalar type
+prefix '$' is inferred for any element of this list not prefixed by '$'
+or '@'. Arrays are implemented in terms of C<split> and C<join>, using
+C<$Config::Config{path_sep}> as the delimiter.
After an environment variable is tied, merely use it like a normal variable.
You may access its value
@path = split(/:/, $PATH);
+ print join("\n", @LD_LIBRARY_PATH), "\n";
or modify it
$PATH .= ":.";
+ push @LD_LIBRARY_PATH, $dir;
+
+however you'd like. Bear in mind, however, that each access to a tied array
+variable requires splitting the environment variable's string anew.
+
+The code:
+
+ use Env qw(@PATH);
+ push @PATH, '.';
+
+is equivalent to:
+
+ use Env qw(PATH);
+ $PATH .= ":.";
+
+except that if C<$ENV{PATH}> started out empty, the second approach leaves
+it with the (odd) value "C<:.>", but the first approach leaves it with "C<.>".
-however you'd like.
To remove a tied environment variable from
the environment, assign it the undefined value
undef $PATH;
+ undef @LD_LIBRARY_PATH;
+
+=head1 LIMITATIONS
+
+On VMS systems, arrays tied to environment variables are read-only. Attempting
+to change anything will cause a warning.
=head1 AUTHOR
Chip Salzenberg E<lt>F<chip@fin.uucp>E<gt>
+and
+Gregor N. Purdy E<lt>F<gregor@focusresearch.com>E<gt>
=cut
sub import {
my ($callpack) = caller(0);
my $pack = shift;
- my @vars = grep /^[A-Za-z_]\w*$/, (@_ ? @_ : keys(%ENV));
+ my @vars = grep /^[\$\@]?[A-Za-z_]\w*$/, (@_ ? @_ : keys(%ENV));
return unless @vars;
- eval "package $callpack; use vars qw("
- . join(' ', map { '$'.$_ } @vars) . ")";
+ @vars = map { m/^[\$\@]/ ? $_ : '$'.$_ } @vars;
+
+ eval "package $callpack; use vars qw(" . join(' ', @vars) . ")";
die $@ if $@;
foreach (@vars) {
- tie ${"${callpack}::$_"}, Env, $_;
+ my ($type, $name) = m/^([\$\@])(.*)$/;
+ if ($type eq '$') {
+ tie ${"${callpack}::$name"}, Env, $name;
+ } else {
+ if ($^O eq 'VMS') {
+ tie @{"${callpack}::$name"}, Env::Array::VMS, $name;
+ } else {
+ tie @{"${callpack}::$name"}, Env::Array, $name;
+ }
+ }
}
}
}
}
+######################################################################
+
+package Env::Array;
+
+use Config;
+use Tie::Array;
+
+@ISA = qw(Tie::Array);
+
+my $sep = $Config::Config{path_sep};
+
+sub TIEARRAY {
+ bless \($_[1]);
+}
+
+sub FETCHSIZE {
+ my ($self) = @_;
+ my @temp = split($sep, $ENV{$$self});
+ return scalar(@temp);
+}
+
+sub STORESIZE {
+ my ($self, $size) = @_;
+ my @temp = split($sep, $ENV{$$self});
+ $#temp = $size - 1;
+ $ENV{$$self} = join($sep, @temp);
+}
+
+sub CLEAR {
+ my ($self) = @_;
+ $ENV{$$self} = '';
+}
+
+sub FETCH {
+ my ($self, $index) = @_;
+ return (split($sep, $ENV{$$self}))[$index];
+}
+
+sub STORE {
+ my ($self, $index, $value) = @_;
+ my @temp = split($sep, $ENV{$$self});
+ $temp[$index] = $value;
+ $ENV{$$self} = join($sep, @temp);
+ return $value;
+}
+
+sub PUSH {
+ my $self = shift;
+ my @temp = split($sep, $ENV{$$self});
+ push @temp, @_;
+ $ENV{$$self} = join($sep, @temp);
+ return scalar(@temp);
+}
+
+sub POP {
+ my ($self) = @_;
+ my @temp = split($sep, $ENV{$$self});
+ my $result = pop @temp;
+ $ENV{$$self} = join($sep, @temp);
+ return $result;
+}
+
+sub UNSHIFT {
+ my $self = shift;
+ my @temp = split($sep, $ENV{$$self});
+ my $result = unshift @temp, @_;
+ $ENV{$$self} = join($sep, @temp);
+ return $result;
+}
+
+sub SHIFT {
+ my ($self) = @_;
+ my @temp = split($sep, $ENV{$$self});
+ my $result = shift @temp;
+ $ENV{$$self} = join($sep, @temp);
+ return $result;
+}
+
+sub SPLICE {
+ my $self = shift;
+ my $offset = shift;
+ my $length = shift;
+ my @temp = split($sep, $ENV{$$self});
+ if (wantarray) {
+ my @result = splice @temp, $self, $offset, $length, @_;
+ $ENV{$$self} = join($sep, @temp);
+ return @result;
+ } else {
+ my $result = scalar splice @temp, $offset, $length, @_;
+ $ENV{$$self} = join($sep, @temp);
+ return $result;
+ }
+}
+
+######################################################################
+
+package Env::Array::VMS;
+use Tie::Array;
+
+@ISA = qw(Tie::Array);
+
+sub TIEARRAY {
+ bless \($_[1]);
+}
+
+sub FETCHSIZE {
+ my ($self) = @_;
+ my $i = 0;
+ while ($i < 127 and defined $ENV{$$self . ';' . $i}) { $i++; };
+ return $i;
+}
+
+sub FETCH {
+ my ($self, $index) = @_;
+ return $ENV{$$self . ';' . $index};
+}
+
1;
--- /dev/null
+#!./perl
+
+$| = 1;
+
+BEGIN {
+ chdir 't' if -d 't';
+ unshift @INC, '../lib';
+}
+
+if ($^O eq 'VMS') {
+ print "1..11\n";
+ foreach (1..11) { print "ok $_ # skipped for VMS\n"; }
+ exit 0;
+}
+
+use Env qw(@FOO);
+use vars qw(@BAR);
+
+sub array_equal
+{
+ my ($a, $b) = @_;
+ return 0 unless scalar(@$a) == scalar(@$b);
+ for my $i (0..scalar(@$a) - 1) {
+ return 0 unless $a->[$i] eq $b->[$i];
+ }
+ return 1;
+}
+
+sub test
+{
+ my ($desc, $code) = @_;
+
+ &$code;
+
+ print "# $desc...\n";
+ print "# FOO = (", join(", ", @FOO), ")\n";
+ print "# BAR = (", join(", ", @BAR), ")\n";
+
+ if (defined $check) { print "not " unless &$check; }
+ else { print "not " unless array_equal(\@FOO, \@BAR); }
+
+ print "ok ", ++$i, "\n";
+}
+
+print "1..11\n";
+
+test "Assignment", sub {
+ @FOO = qw(a B c);
+ @BAR = qw(a B c);
+};
+
+test "Storing", sub {
+ $FOO[1] = 'b';
+ $BAR[1] = 'b';
+};
+
+test "Truncation", sub {
+ $#FOO = 0;
+ $#BAR = 0;
+};
+
+test "Push", sub {
+ push @FOO, 'b', 'c';
+ push @BAR, 'b', 'c';
+};
+
+test "Pop", sub {
+ pop @FOO;
+ pop @BAR;
+};
+
+test "Shift", sub {
+ shift @FOO;
+ shift @BAR;
+};
+
+test "Push", sub {
+ push @FOO, 'c';
+ push @BAR, 'c';
+};
+
+test "Unshift", sub {
+ unshift @FOO, 'a';
+ unshift @BAR, 'a';
+};
+
+test "Reverse", sub {
+ @FOO = reverse @FOO;
+ @BAR = reverse @BAR;
+};
+
+test "Sort", sub {
+ @FOO = sort @FOO;
+ @BAR = sort @BAR;
+};
+
+test "Splice", sub {
+ splice @FOO, 1, 1, 'B';
+ splice @BAR, 1, 1, 'B';
+};
projects / p5sagit/p5-mst-13.2.git / commitdiff