+ # not reached
+ }->();
+
+will rightfully set C<$num> to C<26>.
+
+=head2 C<uplevel $code, @args, $context>
+
+Executes the code reference C<$code> with arguments C<@args> as if it were located at the subroutine stack frame pointed by C<$context>, effectively fooling C<caller> and C<die> into believing that the call actually happened higher in the stack.
+The code is executed in the context of the C<uplevel> call, and what it returns is returned as-is by C<uplevel>.
+
+ sub target {
+ faker(@_);
+ }
+
+ sub faker {
+ uplevel {
+ map { 1 / $_ } @_;
+ } @_ => CALLER(1);
+ }
+
+ my @inverses = target(1, 2, 4); # @inverses contains (0, 0.5, 0.25)
+ my $count = target(1, 2, 4); # $count is 3
+
+L<Sub::Uplevel> also implements a pure-Perl version of C<uplevel>.
+Both are identical, with the following caveats :
+
+=over 4
+
+=item *
+
+The L<Sub::Uplevel> implementation of C<uplevel> may execute a code reference in the context of B<any> upper stack frame.
+The L<Scope::Upper> version can only uplevel to a B<subroutine> stack frame, and will croak if you try to target an C<eval> or a format.
+
+=item *
+
+Exceptions thrown from the code called by this version of C<uplevel> will not be caught by C<eval> blocks between the target frame and the uplevel call, while they will for L<Sub::Uplevel>'s version.
+This means that :
+
+ eval {
+ sub {
+ local $@;
+ eval {
+ sub {
+ uplevel { die 'wut' } CALLER(2); # for Scope::Upper
+ # uplevel(3, sub { die 'wut' }) # for Sub::Uplevel
+ }->();
+ };
+ print "inner block: $@";
+ $@ and exit;
+ }->();
+ };
+ print "outer block: $@";
+
+will print "inner block: wut..." with L<Sub::Uplevel> and "outer block: wut..." with L<Scope::Upper>.
+
+=item *
+
+L<Sub::Uplevel> globally overrides the Perl keyword C<caller>, while L<Scope::Upper> does not.
+
+=back
+
+A simple wrapper lets you mimic the interface of L<Sub::Uplevel/uplevel> :
+
+ use Scope::Upper;
+
+ sub uplevel {
+ my $frame = shift;
+ my $code = shift;
+ my $cxt = Scope::Upper::CALLER($frame);
+ &Scope::Upper::uplevel($code => @_ => $cxt);
+ }
+
+Albeit the three exceptions listed above, it passes all the tests of L<Sub::Uplevel>.
+
+=head1 CONSTANTS
+
+=head2 C<SU_THREADSAFE>
+
+True iff the module could have been built when thread-safety features.
+
+=head1 WORDS
+
+=head2 Constants
+
+=head3 C<TOP>
+
+Returns the context that currently represents the highest scope.
+
+=head3 C<HERE>
+
+The context of the current scope.
+
+=head2 Getting a context from a context
+
+For any of those functions, C<$from> is expected to be a context.
+When omitted, it defaults to the the current context.
+
+=head3 C<UP $from>
+
+The context of the scope just above C<$from>.
+
+=head3 C<SUB $from>
+
+The context of the closest subroutine above C<$from>.
+Note that C<$from> is returned if it is already a subroutine context ; hence C<SUB SUB == SUB>.
+
+=head3 C<EVAL $from>
+
+The context of the closest eval above C<$from>.
+Note that C<$from> is returned if it is already an eval context ; hence C<EVAL EVAL == EVAL>.
+
+=head2 Getting a context from a level
+
+Here, C<$level> should denote a number of scopes above the current one.
+When omitted, it defaults to C<0> and those functions return the same context as L</HERE>.
+
+=head3 C<SCOPE $level>
+
+The C<$level>-th upper context, regardless of its type.
+
+=head3 C<CALLER $level>
+
+The context of the C<$level>-th upper subroutine/eval/format.
+It kind of corresponds to the context represented by C<caller $level>, but while e.g. C<caller 0> refers to the caller context, C<CALLER 0> will refer to the top scope in the current context.
+
+=head2 Examples
+
+Where L</reap> fires depending on the C<$cxt> :
+
+ sub {
+ eval {
+ sub {
+ {
+ reap \&cleanup => $cxt;
+ ...
+ } # $cxt = SCOPE(0), or HERE
+ ...
+ }->(); # $cxt = SCOPE(1), or UP, or SUB, or CALLER, or CALLER(0)
+ ...
+ }; # $cxt = SCOPE(2), or UP UP, or UP SUB, or EVAL, or CALLER(1)
+ ...
+ }->(); # $cxt = SCOPE(3), or SUB UP SUB, or SUB EVAL, or CALLER(2)
+ ...
+
+Where L</localize>, L</localize_elem> and L</localize_delete> act depending on the C<$cxt> :
+
+ sub {
+ eval {
+ sub {
+ {
+ localize '$x' => 1 => $cxt;
+ # $cxt = SCOPE(0), or HERE
+ ...
+ }
+ # $cxt = SCOPE(1), or UP, or SUB, or CALLER, or CALLER(0)
+ ...
+ }->();
+ # $cxt = SCOPE(2), or UP UP, or UP SUB, or EVAL, or CALLER(1)
+ ...
+ };
+ # $cxt = SCOPE(3), or SUB UP SUB, or SUB EVAL, or CALLER(2)
+ ...