This is 0.07

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

diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm
index fc3224eea7c2df138739235f521e3f29f22793bb..3b801161f5ce315a24e70bc2041a7de7154f2134 100644 (file)
--- a/lib/Scope/Upper.pm
+++ b/lib/Scope/Upper.pm
@@ -9,13 +9,13 @@ Scope::Upper - Act on upper scopes.
 
 =head1 VERSION
 
 
 =head1 VERSION
 

-Version 0.06
+Version 0.07

 
 =cut
 
 our $VERSION;
 BEGIN {
 
 =cut
 
 our $VERSION;
 BEGIN {

- $VERSION = '0.06';
+ $VERSION = '0.07';

 }
 
 =head1 SYNOPSIS
 }
 
 =head1 SYNOPSIS


@@ -79,20 +79,32 @@ BEGIN {
 
 =head1 DESCRIPTION
 
 
 =head1 DESCRIPTION
 

-This module lets you defer actions that will take place when the control flow returns into an upper scope.
-Currently, you can hook an upper scope end, or localize variables, array/hash values or deletions of elements in higher contexts.
-You can also return to an upper level and know which context was in use then.
+This module lets you defer actions I<at run-time> that will take place when the control flow returns into an upper scope.
+Currently, you can:
+
+=over 4
+
+=item *
+
+hook an upper scope end with L</reap> ;
+
+=item *
+
+localize variables, array/hash values or deletions of elements in higher contexts with respectively L</localize>, L</localize_elem> and L</localize_delete> ;
+
+=item *
+
+return values immediately to an upper level with L</unwind>, and know which context was in use then with L</want_at>.
+
+=back

 
 =head1 FUNCTIONS
 
 In all those functions, C<$context> refers to the target scope.
 
 
 =head1 FUNCTIONS
 
 In all those functions, C<$context> refers to the target scope.
 

-You have to use one or a combination of L</WORDS> to build the C<$context> to pass to these functions.
+You have to use one or a combination of L</WORDS> to build the C<$context> passed to these functions.

 This is needed in order to ensure that the module still works when your program is ran in the debugger.
 This is needed in order to ensure that the module still works when your program is ran in the debugger.

-Don't try to use a raw value or things will get messy.
-
-The only thing you can assume is that it is an I<absolute> indicator of the frame.
-This means that you can safely store it at some point and use it when needed, and it will still denote the original scope.
+The only thing you can assume is that it is an I<absolute> indicator of the frame, which means that you can safely store it at some point and use it when needed, and it will still denote the original scope.

 
 =cut
 
 
 =cut
 


@@ -169,7 +181,7 @@ C<$key> is ignored.
 
 =head2 C<unwind @values, $context>
 
 
 =head2 C<unwind @values, $context>
 

-Returns C<@values> I<from> the context pointed by C<$context>, i.e. from the subroutine, eval or format just above C<$context>.
+Returns C<@values> I<from> the context pointed by C<$context>, i.e. from the subroutine, eval or format just above C<$context>, and immediately restart the program flow at this point - thus effectively returning to (or from, depending on how you see it) an upper context.

 
 The upper context isn't coerced onto C<@values>, which is hence always evaluated in list context.
 This means that
 
 The upper context isn't coerced onto C<@values>, which is hence always evaluated in list context.
 This means that


@@ -219,10 +231,12 @@ The context of the scope just above C<$from>.
 =head3 C<SUB $from>
 
 The context of the closest subroutine 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>.
 
 =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
 
 
 =head2 Getting a context from a level
 


@@ -238,6 +252,64 @@ The C<$level>-th upper context, regardless of its type.
 The context of the C<$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.
 
 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)
+     ...
+    }->();
+    # $cxt = SCOPE(4), UP SUB UP SUB, or UP SUB EVAL, or UP CALLER(2), or TOP
+    ...
+
+Where L</unwind> and L</want_at> point to depending on the C<$cxt>:
+
+    sub {
+     eval {
+      sub {
+       {
+        unwind @things => $cxt;
+        ...
+       }
+       ...
+      }->(); # $cxt = SCOPE(0 .. 1), or HERE, or UP, or SUB, 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)
+    ...
+

 =head1 EXPORT
 
 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'>.
 =head1 EXPORT
 
 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'>.


@@ -278,11 +350,12 @@ Consider those examples:
 
 The first case is "solved" by moving the C<local> before the C<reap>, and the second by using L</localize> instead of L</reap>.
 
 
 The first case is "solved" by moving the C<local> before the C<reap>, and the second by using L</localize> instead of L</reap>.
 

-L</reap>, L</localize> and L</localize_elem> effects can't cross C<BEGIN> blocks, hence calling those functions in C<import> is deemed to be useless.
+The effects of L</reap>, L</localize> and L</localize_elem> can't cross C<BEGIN> blocks, hence calling those functions in C<import> is deemed to be useless.

 This is an hopeless case because C<BEGIN> blocks are executed once while localizing constructs should do their job at each run.
 This is an hopeless case because C<BEGIN> blocks are executed once while localizing constructs should do their job at each run.

+However, it's possible to hook the end of the current scope compilation with L<B::Hooks::EndOfScope>.

 
 Some rare oddities may still happen when running inside the debugger.
 
 Some rare oddities may still happen when running inside the debugger.

-It may help to use a perl higher than 5.8.9 or 5.10.0, as they contain some context fixes.
+It may help to use a perl higher than 5.8.9 or 5.10.0, as they contain some context-related fixes.

 
 =head1 DEPENDENCIES
 
 
 =head1 DEPENDENCIES