X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FScope%2FUpper.pm;h=f2a97c5a5c201c9387d15c0643f5a48e405123f5;hb=0f7334e9f0acbdac38c362be678bd6ecb658cb0b;hp=6ef56c0b9da2dbebed800056b1a5fa8eb28dbe6c;hpb=c6e995c68b5384510061cde2d433e9506a3935f5;p=perl%2Fmodules%2FScope-Upper.git
diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm
index 6ef56c0..f2a97c5 100644
--- a/lib/Scope/Upper.pm
+++ b/lib/Scope/Upper.pm
@@ -128,6 +128,28 @@ L :
target('hello'); # "hello from Uplevel::target()"
+L and L :
+
+ use Scope::Upper qw;
+
+ my $uid;
+
+ {
+ $uid = uid();
+ {
+ if ($uid eq uid(UP)) { # yes
+ ...
+ }
+ if (validate_uid($uid)) { # yes
+ ...
+ }
+ }
+ }
+
+ if (validate_uid($uid)) { # no
+ ...
+ }
+
=head1 DESCRIPTION
This module lets you defer actions I that will take place when the control flow returns into an upper scope.
@@ -149,7 +171,11 @@ return values immediately to an upper level with L, and know which cont
=item *
-execute a subroutine in the setting of an upper subroutine stack frame with L.
+execute a subroutine in the setting of an upper subroutine stack frame with L ;
+
+=item *
+
+uniquely identify contextes with L and L.
=back
@@ -353,6 +379,73 @@ A simple wrapper lets you mimic the interface of L :
Albeit the three exceptions listed above, it passes all the tests of L.
+=head2 C
+
+Returns an unique identifier (UID) for the context (or dynamic scope) pointed by C<$context>, or for the current context if C<$context> is omitted.
+This UID will only be valid for the life time of the context it represents, and another UID will be generated next time the same scope is executed.
+
+ my $uid;
+
+ {
+ $uid = uid;
+ if ($uid eq uid()) { # yes, this is the same context
+ ...
+ }
+ {
+ if ($uid eq uid()) { # no, we are one scope below
+ ...
+ }
+ if ($uid eq uid(UP)) { # yes, UP points to the same scope as $uid
+ ...
+ }
+ }
+ }
+
+ # $uid is now invalid
+
+ {
+ if ($uid eq uid()) { # no, this is another block
+ ...
+ }
+ }
+
+For example, each loop iteration gets its own UID :
+
+ my %uids;
+
+ for (1 .. 5) {
+ my $uid = uid;
+ $uids{$uid} = $_;
+ }
+
+ # %uids has 5 entries
+
+The UIDs are not guaranteed to be numbers, so you must use the C operator to compare them.
+
+To check whether a given UID is valid, you can use the L function.
+
+=head2 C
+
+Returns true if and only if C<$uid> is the UID of a currently valid context (that is, it designates a scope that is higher than the current one in the call stack).
+
+ my $uid;
+
+ {
+ $uid = uid();
+ if (validate_uid($uid)) { # yes
+ ...
+ }
+ {
+ if (validate_uid($uid)) { # yes
+ ...
+ }
+ }
+ }
+
+ if (validate_uid($uid)) { # no
+ ...
+ }
+
=head1 CONSTANTS
=head2 C
@@ -484,6 +577,7 @@ our %EXPORT_TAGS = (
localize localize_elem localize_delete
unwind want_at
uplevel
+ uid validate_uid
> ],
words => [ qw ],
consts => [ qw ],