Show unwind() and want_at() in the synopsys and the samples

[perl/modules/Scope-Upper.git] / lib / Scope / Upper.pm

diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm
index ca8ecc98638cb6f05c2375d622c25271410d39be..ba26e61291537cb5049c51732a7ecc25036f8247 100644 (file)
--- a/lib/Scope/Upper.pm
+++ b/lib/Scope/Upper.pm
@@ -56,6 +56,26 @@ BEGIN {
      ...
     } # "pie: done" is printed
 
+    package Z;
+
+    use Scope::Upper qw/unwind want_at :words/;
+
+    sub try (&) {
+     my @result = shift->();
+     my $cx = SUB UP SUB;
+     unwind +(want_at($cx) ? @result : scalar @result) => $cx;
+    }
+
+    ...
+
+    sub zap {
+     try {
+      return @things; # returns to try() and then outside zap()
+     }
+    }
+
+    my @what = zap(); # @what contains @things
+
 =head1 DESCRIPTION
 
 This module lets you defer actions that will take place when the control flow returns into an upper scope.
@@ -136,6 +156,15 @@ C<$key> is ignored.
 
 =back
 
+=head2 C<unwind @values, $level>
+
+Returns C<@values> I<from> the context indicated by C<$level>, i.e. from the subroutine, eval or format just above C<$level>.
+The upper level isn't coerced onto C<@values>, which is hence always evaluated in list context.
+
+=head2 C<want_at $level>
+
+Like C<wantarray>, but for the subroutine/eval/format context just above C<$level>.
+
 =head1 WORDS
 
 =head2 C<TOP>
@@ -164,11 +193,15 @@ The level of the closest eval context above C<$from>.
 
 If C<$from> is omitted in any of those functions, the current level is used as the reference level.
 
+=head2 C<CALLER $stack>
+
+The level corresponding to the stack referenced by C<caller $stack>.
+
 =head1 EXPORT
 
-The functions L</reap>, L</localize>, L</localize_elem> and L</localize_delete> are only exported on request, either individually or by the tags C<':funcs'> and C<':all'>.
+The functions L</reap>, L</localize>, L</localize_elem>, L</localize_delete>,  L</unwind> and L</want_at> are only exported on request, either individually or by the tags C<':funcs'> and C<':all'>.
 
-Same goes for the words L</TOP>, L</HERE>, L</UP>, L</DOWN>, L</SUB> and L</EVAL> that are only exported on request, individually or by the tags C<':words'> and C<':all'>.
+Same goes for the words L</TOP>, L</HERE>, L</UP>, L</DOWN>, L</SUB>, L</EVAL> and L</CALLER> that are only exported on request, individually or by the tags C<':words'> and C<':all'>.
 
 =cut
 
@@ -176,8 +209,8 @@ use base qw/Exporter/;
 
 our @EXPORT      = ();
 our %EXPORT_TAGS = (
- funcs => [ qw/reap localize localize_elem localize_delete/ ],
- words => [ qw/TOP HERE UP DOWN SUB EVAL/ ],
+ funcs => [ qw/reap localize localize_elem localize_delete unwind want_at/ ],
+ words => [ qw/TOP HERE UP DOWN SUB EVAL CALLER/ ],
 );
 our @EXPORT_OK   = map { @$_ } values %EXPORT_TAGS;
 $EXPORT_TAGS{'all'} = [ @EXPORT_OK ];