X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FScope%2FUpper.pm;h=b114f2f0130e6faa46309a6d41c0e6260cd1888c;hb=780a9a13dd0a14aabed9c7c91613d4ad75190c9f;hp=a6d85d26d4d338219ee9c4bbcf24e86692af2bc3;hpb=99122cf481918c10d5c22719c89b5af960084f77;p=perl%2Fmodules%2FScope-Upper.git

diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm
index a6d85d2..b114f2f 100644
--- a/lib/Scope/Upper.pm
+++ b/lib/Scope/Upper.pm
@@ -1,5 +1,7 @@
 package Scope::Upper;
 
+use 5.006_001;
+
 use strict;
 use warnings;
 
@@ -9,13 +11,13 @@ Scope::Upper - Act on upper scopes.
 
 =head1 VERSION
 
-Version 0.21
+Version 0.31
 
 =cut
 
 our $VERSION;
 BEGIN {
- $VERSION = '0.21';
+ $VERSION = '0.31';
 }
 
 =head1 SYNOPSIS
@@ -182,7 +184,7 @@ execute a subroutine in the setting of an upper subroutine stack frame with L</u
 
 =item *
 
-uniquely identify contextes with L</uid> and L</validate_uid>.
+uniquely identify contexts with L</uid> and L</validate_uid>.
 
 =back
 
@@ -290,7 +292,7 @@ A glob, in which case C<$key> is ignored and the call is equivalent to C<local *
 
 =item *
 
-A string beginning with C<'@'> or C<'%'>, for which the call is equivalent to respectiveley C<local $a[$key]; delete $a[$key]> and C<local $h{$key}; delete $h{$key}>.
+A string beginning with C<'@'> or C<'%'>, for which the call is equivalent to respectively C<local $a[$key]; delete $a[$key]> and C<local $h{$key}; delete $h{$key}>.
 
 =item *
 
@@ -603,7 +605,7 @@ 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.
+When omitted, it defaults to the current context.
 
 =head3 C<UP>
 
@@ -611,6 +613,7 @@ When omitted, it defaults to the the current context.
     my $upper_context = UP $from;
 
 The context of the scope just above C<$from>.
+If C<$from> points to the top-level scope in the current stack, then a warning is emitted and C<$from> is returned (see L</DIAGNOSTICS> for details).
 
 =head3 C<SUB>
 
@@ -618,7 +621,8 @@ The context of the scope just above C<$from>.
     my $sub_context = 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>.
+If C<$from> already designates a subroutine context, then it is returned as-is ; hence C<SUB SUB == SUB>.
+If no subroutine context is present in the call stack, then a warning is emitted and the current context is returned (see L</DIAGNOSTICS> for details).
 
 =head3 C<EVAL>
 
@@ -626,7 +630,8 @@ Note that C<$from> is returned if it is already a subroutine context ; hence C<S
     my $eval_context = 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>.
+If C<$from> already designates an eval context, then it is returned as-is ; hence C<EVAL EVAL == EVAL>.
+If no eval context is present in the call stack, then a warning is emitted and the current context is returned (see L</DIAGNOSTICS> for details).
 
 =head2 Getting a context from a level
 
@@ -639,6 +644,7 @@ When omitted, it defaults to C<0> and those functions return the same context as
     my $context = SCOPE $level;
 
 The C<$level>-th upper context, regardless of its type.
+If C<$level> points above the top-level scope in the current stack, then a warning is emitted and the top-level context is returned (see L</DIAGNOSTICS> for details).
 
 =head3 C<CALLER>
 
@@ -647,6 +653,7 @@ 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 $level>, but while e.g. C<caller 0> refers to the caller context, C<CALLER 0> will refer to the top scope in the current context.
+If C<$level> points above the top-level scope in the current stack, then a warning is emitted and the top-level context is returned (see L</DIAGNOSTICS> for details).
 
 =head2 Examples
 
@@ -710,6 +717,19 @@ Where L</unwind>, L</yield>, L</want_at>, L</context_info> and L</uplevel> point
     # (*) Note that uplevel() will croak if you pass that scope frame,
     #     because it cannot target eval scopes.
 
+=head1 DIAGNOSTICS
+
+=head2 C<Cannot target a scope outside of the current stack>
+
+This warning is emitted when L</UP>, L</SCOPE> or L</CALLER> end up pointing to a context that is above the top-level context of the current stack.
+It indicates that you tried to go higher than the main scope, or to point across a C<DESTROY> method, a signal handler, an overloaded or tied method call, a C<require> statement or a C<sort> callback.
+In this case, the resulting context is the highest reachable one.
+
+=head2 C<No targetable %s scope in the current stack>
+
+This warning is emitted when you ask for an L</EVAL> or L</SUB> context and no such scope can be found in the call stack.
+The resulting context is the current one.
+
 =head1 EXPORT
 
 The functions L</reap>, L</localize>, L</localize_elem>, L</localize_delete>,  L</unwind>, L</yield>, L</leave>, L</want_at>, L</context_info> and L</uplevel> are only exported on request, either individually or by the tags C<':funcs'> and C<':all'>.
@@ -740,6 +760,8 @@ $EXPORT_TAGS{'all'} = [ @EXPORT_OK ];
 
 =head1 CAVEATS
 
+It is not possible to act upon a scope that belongs to another perl 'stack', i.e. to target a scope across a C<DESTROY> method, a signal handler, an overloaded or tied method call, a C<require> statement or a C<sort> callback.
+
 Be careful that local variables are restored in the reverse order in which they were localized.
 Consider those examples:
 
@@ -787,9 +809,12 @@ when the runloop callback is replaced by another module.
 
 In those three cases, L</uplevel> will look for a C<goto &sub> statement in its callback and, if there is one, throw an exception before executing the code.
 
-Moreover, in order to handle C<goto> statements properly, L</uplevel> currently has to suffer a run-time overhead proportional to the size of the the callback in every case (with a small ratio), and proportional to the size of B<all> the code executed as the result of the L</uplevel> call (including subroutine calls inside the callback) when a C<goto> statement is found in the L</uplevel> callback.
+Moreover, in order to handle C<goto> statements properly, L</uplevel> currently has to suffer a run-time overhead proportional to the size of the callback in every case (with a small ratio), and proportional to the size of B<all> the code executed as the result of the L</uplevel> call (including subroutine calls inside the callback) when a C<goto> statement is found in the L</uplevel> callback.
 Despite this shortcoming, this XS version of L</uplevel> should still run way faster than the pure-Perl version from L<Sub::Uplevel>.
 
+Starting from C<perl> 5.19.4, it is unfortunately no longer possible to reliably throw exceptions from L</uplevel>'d code while the debugger is in use.
+This may be solved in a future version depending on how the core evolves.
+
 =head1 DEPENDENCIES
 
 L<perl> 5.6.1.
@@ -797,7 +822,7 @@ L<perl> 5.6.1.
 A C compiler.
 This module may happen to build with a C++ compiler as well, but don't rely on it, as no guarantee is made in this regard.
 
-L<XSLoader> (core since perl 5.006).
+L<XSLoader> (core since perl 5.6.0).
 
 =head1 SEE ALSO
 
@@ -814,7 +839,7 @@ L<Scope::Escape>.
 
 =head1 AUTHOR
 
-Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
+Vincent Pit C<< <vpit at cpan.org> >>.
 
 You can contact me by mail or on C<irc.perl.org> (vincent).
 
@@ -829,17 +854,18 @@ You can find documentation for this module with the perldoc command.
 
     perldoc Scope::Upper
 
-Tests code coverage report is available at L<http://www.profvince.com/perl/cover/Scope-Upper>.
-
 =head1 ACKNOWLEDGEMENTS
 
 Inspired by Ricardo Signes.
 
+The reimplementation of a large part of this module for perl 5.24 was provided by David Mitchell.
+His work was sponsored by the Perl 5 Core Maintenance Grant from The Perl Foundation.
+
 Thanks to Shawn M. Moore for motivation.
 
 =head1 COPYRIGHT & LICENSE
 
-Copyright 2008,2009,2010,2011,2012,2013 Vincent Pit, all rights reserved.
+Copyright 2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019 Vincent Pit, all rights reserved.
 
 This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.