=head1 DESCRIPTION
-This module provides an utility routine that can be used to temporarily change the value of a variable, until the end of the current scope is reached where the original value of the variable is restored.
+This module provides an utility routine that can be used to temporarily change the value of a scalar, array or hash variable, until the end of the current scope is reached where the original value of the variable is restored.
It is similar to C<local>, except that it can be applied onto lexicals as well as globals, and that it replaces values by copying the new value into the container variable instead of by aliasing.
=cut
+use Variable::Magic 0.51;
+
use Scope::Upper;
=head1 FUNCTIONS
temp $var;
temp $var = $value;
-Temporarily replace the value of the lexical or global variable C<$var> by C<$value>, or by C<undef> if C<$value> is omitted, until the end of the current scope.
-Any subsequent assignments to C<$var> in the current (or any inferior) scope will not affect the original value which will be restored into the variable at scope end.
+ temp @var;
+ temp @var = \@value;
+
+ temp %var;
+ temp %var = \%value;
+
+Temporarily replaces the value of the lexical or global variable C<$var> by C<$value> (respectively C<@var> by C<@value>, C<%var> by C<%value>), or by C<undef> if C<$value> is omitted (respectively empties C<@var> and C<%var> if the second argument is omitted), until the end of the current scope.
+Any subsequent assignments to this variable in the current (or any inferior) scope will not affect the original value which will be restored into the variable at scope end.
Several C<temp> calls can be made onto the same variable, and the restore are processed in reverse order.
-Note that destructors associated with C<$var> will B<not> be called when C<temp> sets the temporary value, but only at the natural end of life of the variable (i.e. at the end of the scope).
-They will trigger after any destructor associated with the replacement C<$value>.
+Note that destructors associated with the variable will B<not> be called when C<temp> sets the temporary value, but only at the natural end of life of the variable.
+They will trigger after any destructor associated with the replacement value.
Due to a shortcoming in the handling of the C<\$> prototype, which was addressed in C<perl> 5.14, the pseudo-statement C<temp $var = $value> will cause compilation errors on C<perl> 5.12.x and below.
If you want your code to run on these versions of C<perl>, you are encouraged to use L</set_temp> instead.
=cut
-sub temp (\$) :lvalue {
- my $var = $_[0];
- my $save = $$var;
- &Scope::Upper::reap(sub { $$var = $save } => Scope::Upper::UP);
- $$var;
+my $wiz;
+$wiz = Variable::Magic::wizard(
+ data => sub { $_[1] },
+ set => sub {
+ my ($token, $var) = @_;
+ &Variable::Magic::dispell($token, $wiz);
+ if (ref $var eq 'ARRAY') {
+ @$var = @$$token;
+ } else {
+ %$var = %$$token;
+ }
+ return;
+ },
+ free => sub {
+ my ($token, $var) = @_;
+ # We need Variable::Magic 0.51 so that dispell in free does not crash.
+ &Variable::Magic::dispell($token, $wiz);
+ if (ref $var eq 'ARRAY') {
+ @$var = ();
+ } else {
+ %$var = ();
+ }
+ },
+);
+
+sub temp (\[$@%]) :lvalue {
+ my $var = $_[0];
+ my $target = Scope::Upper::UP;
+ my $ret;
+ my $type = ref $var;
+ if ($type eq 'ARRAY') {
+ my @save = @$var;
+ &Scope::Upper::reap(sub { @$var = @save } => $target);
+ my $token;
+ Variable::Magic::cast($token, $wiz, $var);
+ $ret = \$token;
+ } elsif ($type eq 'HASH') {
+ my %save = %$var;
+ &Scope::Upper::reap(sub { %$var = %save } => $target);
+ my $token;
+ Variable::Magic::cast($token, $wiz, $var);
+ $ret = \$token;
+ } else { # $type eq 'SCALAR' || $type eq 'REF'
+ my $save = $$var;
+ &Scope::Upper::reap(sub { $$var = $save } => $target);
+ $ret = $var;
+ }
+ $$ret;
}
=head2 C<set_temp>
set_temp $var;
set_temp $var => $value;
+ set_temp @var;
+ set_temp @var => \@value;
+
+ set_temp %var;
+ set_temp %var => \%value;
+
A non-lvalue variant of L</temp> that can be used with any version of C<perl>.
=cut
-sub set_temp (\$;$) {
- my $var = $_[0];
- my $save = $$var;
- &Scope::Upper::reap(sub { $$var = $save } => Scope::Upper::UP);
- $$var = $_[1] if @_ >= 2;
+sub set_temp (\[$@%];$) {
+ my $var = $_[0];
+ my $target = Scope::Upper::UP;
+ my $type = ref $var;
+ if ($type eq 'ARRAY') {
+ my @save = @$var;
+ &Scope::Upper::reap(sub { @$var = @save } => $target);
+ @$var = @_ >= 2 ? @{$_[1]} : ();
+ } elsif ($type eq 'HASH') {
+ my %save = %$var;
+ &Scope::Upper::reap(sub { %$var = %save } => $target);
+ %$var = @_ >= 2 ? %{$_[1]} : ();
+ } else { # $type eq 'SCALAR' || $type eq 'REF'
+ my $save = $$var;
+ &Scope::Upper::reap(sub { $$var = $save } => $target);
+ $$var = $_[1];
+ }
return;
}
our %EXPORT_TAGS = ();
our @EXPORT_OK = qw<temp set_temp>;
-=head1 CAVEATS
-
-Currently only applies to scalar variables.
-
=head1 DEPENDENCIES
L<perl> 5.6.
+L<Exporter> (core since perl 5).
+
L<Scope::Upper>.
-L<Exporter> (core since perl 5).
+L<Variable::Magic> 0.51.
=head1 SEE ALSO
use Variable::Temp 'set_temp';
-use Test::More tests => 7 + 13;
+use Test::More tests => (7 + 2 * 19) * 2 + 6 * 3;
+
+sub describe {
+ my $h = $_[0];
+ return join ', ', map "$_:$h->{$_}", sort keys %$h;
+}
+
+# Lexicals
my $x = 1;
is $x, 1;
}
is $x, 1;
+{
+ my @y = (1, 2);
+ is "@y", "1 2";
+ {
+ set_temp @y => [ 3 ];
+ is "@y", '3';
+ @y = (4, 5, 6);
+ is "@y", '4 5 6';
+ $y[3] = 7;
+ is "@y", '4 5 6 7';
+ }
+ is "@y", "1 2";
+ {
+ set_temp @y => [ 8, 9, 10 ];
+ is "@y", '8 9 10';
+ $y[1] = 11;
+ is "@y", '8 11 10';
+ }
+ is "@y", "1 2";
+ {
+ set_temp @y => [ 12, 13, 14 ];
+ is "@y", '12 13 14';
+ set_temp @y => [ 15, 16];
+ is "@y", '15 16';
+ }
+ is "@y", '1 2';
+ {
+ set_temp @y;
+ is "@y", '';
+ }
+ is "@y", '1 2';
+ {
+ set_temp @y => [ qw<a b c> ];
+ is "@y", 'a b c';
+ {
+ local $y[1] = 'd';
+ is "@y", 'a d c';
+ {
+ local @y[2, 3] = qw<e f>;
+ is "@y", 'a d e f';
+ }
+ is "@y", 'a d c';
+ }
+ is "@y", 'a b c';
+ }
+ is "@y", '1 2';
+}
+
+{
+ my %z = (a => 1);
+ is describe(\%z), 'a:1';
+ {
+ set_temp %z => { b => 2 };
+ is describe(\%z), 'b:2';
+ %z = (c => 3);
+ is describe(\%z), 'c:3';
+ $z{d} = 4;
+ is describe(\%z), 'c:3, d:4';
+ }
+ is describe(\%z), 'a:1';
+ {
+ set_temp %z => { a => 5 };
+ is describe(\%z), 'a:5';
+ $z{a} = 6;
+ is describe(\%z), 'a:6';
+ }
+ is describe(\%z), 'a:1';
+ {
+ set_temp %z => { a => 7, d => 8 };
+ is describe(\%z), 'a:7, d:8';
+ set_temp %z => { d => 9, e => 10 };
+ is describe(\%z), 'd:9, e:10';
+ }
+ is describe(\%z), 'a:1';
+ {
+ set_temp %z;
+ is describe(\%z), '';
+ }
+ is describe(\%z), 'a:1';
+ {
+ set_temp %z => { a => 11, f => 12 };
+ is describe(\%z), 'a:11, f:12';
+ {
+ local $z{a} = 13;
+ is describe(\%z), 'a:13, f:12';
+ {
+ local @z{qw<f g>} = (14, 15);
+ is describe(\%z), 'a:13, f:14, g:15';
+ }
+ is describe(\%z), 'a:13, f:12';
+ }
+ is describe(\%z), 'a:11, f:12';
+ }
+ is describe(\%z), 'a:1';
+}
+
+# Globals
+
our $X = 1;
is $X, 1;
{
is $X, 3;
}
is $X, 1;
+
+{
+ our @Y = (1, 2);
+ is "@Y", "1 2";
+ {
+ set_temp @Y => [ 3 ];
+ is "@Y", '3';
+ @Y = (4, 5, 6);
+ is "@Y", '4 5 6';
+ $Y[3] = 7;
+ is "@Y", '4 5 6 7';
+ }
+ is "@Y", "1 2";
+ {
+ set_temp @Y => [ 8, 9, 10 ];
+ is "@Y", '8 9 10';
+ $Y[1] = 11;
+ is "@Y", '8 11 10';
+ }
+ is "@Y", "1 2";
+ {
+ set_temp @Y => [ 12, 13, 14 ];
+ is "@Y", '12 13 14';
+ set_temp @Y => [ 15, 16];
+ is "@Y", '15 16';
+ }
+ is "@Y", '1 2';
+ {
+ set_temp @Y;
+ is "@Y", '';
+ }
+ is "@Y", '1 2';
+ {
+ set_temp @Y => [ qw<a b c> ];
+ is "@Y", 'a b c';
+ {
+ local $Y[1] = 'd';
+ is "@Y", 'a d c';
+ {
+ local @Y[2, 3] = qw<e f>;
+ is "@Y", 'a d e f';
+ }
+ is "@Y", 'a d c';
+ }
+ is "@Y", 'a b c';
+ }
+ is "@Y", '1 2';
+ {
+ local @Y = qw<A B>;
+ is "@Y", 'A B';
+ }
+ is "@Y", '1 2';
+ {
+ local @Y = qw<C D E>;
+ set_temp @Y => [ qw<F> ];
+ is "@Y", 'F';
+ }
+ is "@Y", '1 2';
+ {
+ set_temp @Y => [ qw<G H I> ];
+ local @Y = qw<J>;
+ is "@Y", 'J';
+ }
+ is "@Y", '1 2';
+}
+
+{
+ our %Z = (a => 1);
+ is describe(\%Z), 'a:1';
+ {
+ set_temp %Z => { b => 2 };
+ is describe(\%Z), 'b:2';
+ %Z = (c => 3);
+ is describe(\%Z), 'c:3';
+ $Z{d} = 4;
+ is describe(\%Z), 'c:3, d:4';
+ }
+ is describe(\%Z), 'a:1';
+ {
+ set_temp %Z => { a => 5 };
+ is describe(\%Z), 'a:5';
+ $Z{a} = 6;
+ is describe(\%Z), 'a:6';
+ }
+ is describe(\%Z), 'a:1';
+ {
+ set_temp %Z => { a => 7, d => 8 };
+ is describe(\%Z), 'a:7, d:8';
+ set_temp %Z => { d => 9, e => 10 };
+ is describe(\%Z), 'd:9, e:10';
+ }
+ is describe(\%Z), 'a:1';
+ {
+ set_temp %Z;
+ is describe(\%Z), '';
+ }
+ is describe(\%Z), 'a:1';
+ {
+ set_temp %Z => { a => 11, f => 12 };
+ is describe(\%Z), 'a:11, f:12';
+ {
+ local $Z{a} = 13;
+ is describe(\%Z), 'a:13, f:12';
+ {
+ local @Z{qw<f g>} = (14, 15);
+ is describe(\%Z), 'a:13, f:14, g:15';
+ }
+ is describe(\%Z), 'a:13, f:12';
+ }
+ is describe(\%Z), 'a:11, f:12';
+ }
+ is describe(\%Z), 'a:1';
+ {
+ local %Z = (A => 1, B => 2);
+ is describe(\%Z), 'A:1, B:2';
+ }
+ is describe(\%Z), 'a:1';
+ {
+ local %Z = (A => 3, C => 4);
+ set_temp %Z => { A => 5, D => 6 };
+ is describe(\%Z), 'A:5, D:6';
+ }
+ is describe(\%Z), 'a:1';
+ {
+ set_temp %Z => { A => 7, E => 8 };
+ local %Z = (A => 9, F => 10);
+ is describe(\%Z), 'A:9, F:10';
+ }
+ is describe(\%Z), 'a:1';
+}
projects / perl / modules / Variable-Temp.git / commitdiff