Implement temp/set_temp on container variables

[perl/modules/Variable-Temp.git] / lib / Variable / Temp.pm

diff --git a/lib/Variable/Temp.pm b/lib/Variable/Temp.pm
index be72888ace01d7b421b3e291464b175232961c1a..5be8073853f332eaf3493bf28263b6e0f20bfba1 100644 (file)
--- a/lib/Variable/Temp.pm
+++ b/lib/Variable/Temp.pm
@@ -34,11 +34,13 @@ BEGIN {
 
 =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
@@ -48,23 +50,72 @@ use Scope::Upper;
     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>
@@ -72,15 +123,33 @@ sub temp (\$) :lvalue {
     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;
 }
 
@@ -96,17 +165,15 @@ our @EXPORT      = ();
 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