package Scope::Upper;
+use 5.006_001;
+
use strict;
use warnings;
=head1 VERSION
-Version 0.19
+Version 0.23
=cut
our $VERSION;
BEGIN {
- $VERSION = '0.19';
+ $VERSION = '0.23';
}
=head1 SYNOPSIS
=item *
-return values immediately to an upper level with L</unwind>, L</yield> and L</leave>, and know which context was in use then with L</want_at> ;
+return values immediately to an upper level with L</unwind>, L</yield> and L</leave> ;
+
+=item *
+
+gather information about an upper context with L</want_at> and L</context_info> ;
=item *
=item *
-uniquely identify contextes with L</uid> and L</validate_uid>.
+uniquely identify contexts with L</uid> and L</validate_uid>.
=back
=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 *
unwind;
unwind @values, $context;
-Returns C<@values> I<from> the subroutine, eval or format context pointed by or just above C<$context>, and immediately restart the program flow at this point - thus effectively returning C<@values> to an upper scope.
+Returns C<@values> I<from> the subroutine, eval or format context pointed by or just above C<$context>, and immediately restarts the program flow at this point - thus effectively returning C<@values> to an upper scope.
If C<@values> is empty, then the C<$context> parameter is optional and defaults to the current context (making the call equivalent to a bare C<return;>) ; otherwise it is mandatory.
The upper context isn't coerced onto C<@values>, which is hence always evaluated in list context.
yield;
yield @values, $context;
-Returns C<@values> I<from> the context pointed by or just above C<$context>, and immediately restart the program flow at this point.
+Returns C<@values> I<from> the context pointed by or just above C<$context>, and immediately restarts the program flow at this point.
If C<@values> is empty, then the C<$context> parameter is optional and defaults to the current context ; otherwise it is mandatory.
L</yield> differs from L</unwind> in that it can target I<any> upper scope (besides a C<s///e> substitution context) and not necessarily a sub, an eval or a format.
} @things;
Like for L</unwind>, the upper context isn't coerced onto C<@values>.
+You can use the fifth value returned by L</context_info> to handle context coercion.
=head2 C<leave>
leave @values;
Immediately returns C<@values> from the current block, whatever it may be (besides a C<s///e> substitution context).
-C<leave> is actually a synonym for C<unwind HERE>, while C<leave @values> is a synonym for C<yield @values, HERE>.
+C<leave> is actually a synonym for C<yield HERE>, while C<leave @values> is a synonym for C<yield @values, HERE>.
+
+Like for L</yield>, you can use the fifth value returned by L</context_info> to handle context coercion.
=head2 C<want_at>
my $want = want_at;
my $want = want_at $context;
-Like C<wantarray>, but for the subroutine/eval/format at or just above C<$context>.
+Like L<perlfunc/wantarray>, but for the subroutine, eval or format context located at or just above C<$context>.
-The previous example can then be "corrected" :
+It can be used to revise the example showed in L</unwind> :
my $num = sub {
my @a = ('a' .. 'z');
will rightfully set C<$num> to C<26>.
+=head2 C<context_info>
+
+ my ($package, $filename, $line, $subroutine, $hasargs,
+ $wantarray, $evaltext, $is_require, $hints, $bitmask,
+ $hinthash) = context_info $context;
+
+Gives information about the context denoted by C<$context>, akin to what L<perlfunc/caller> provides but not limited only to subroutine, eval and format contexts.
+When C<$context> is omitted, it defaults to the current context.
+
+The returned values are, in order :
+
+=over 4
+
+=item *
+
+I<(index 0)> : the namespace in use when the context was created ;
+
+=item *
+
+I<(index 1)> : the name of the file at the point where the context was created ;
+
+=item *
+
+I<(index 2)> : the line number at the point where the context was created ;
+
+=item *
+
+I<(index 3)> : the name of the subroutine called for this context, or C<undef> if this is not a subroutine context ;
+
+=item *
+
+I<(index 4)> : a boolean indicating whether a new instance of C<@_> was set up for this context, or C<undef> if this is not a subroutine context ;
+
+=item *
+
+I<(index 5)> : the context (in the sense of L<perlfunc/wantarray>) in which the context (in our sense) is executed ;
+
+=item *
+
+I<(index 6)> : the contents of the string being compiled for this context, or C<undef> if this is not an eval context ;
+
+=item *
+
+I<(index 7)> : a boolean indicating whether this eval context was created by C<require>, or C<undef> if this is not an eval context ;
+
+=item *
+
+I<(index 8)> : the value of the lexical hints in use when the context was created ;
+
+=item *
+
+I<(index 9)> : a bit string representing the warnings in use when the context was created ;
+
+=item *
+
+I<(index 10)> : a reference to the lexical hints hash in use when the context was created (only on perl 5.10 or greater).
+
+=back
+
=head2 C<uplevel>
my @ret = uplevel { ...; return @ret };
=head2 Getting a context from a context
For any of those functions, C<$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>
# $cxt = SCOPE(4), UP SUB UP SUB = UP SUB EVAL = UP CALLER(2) = TOP
...
-Where L</unwind>, L</yield>, L</want_at> and L</uplevel> point to depending on the C<$cxt>:
+Where L</unwind>, L</yield>, L</want_at>, L</context_info> and L</uplevel> point to depending on the C<$cxt>:
sub {
eval {
=head1 EXPORT
-The functions L</reap>, L</localize>, L</localize_elem>, L</localize_delete>, L</unwind>, L</yield>, L</leave>, L</want_at> and L</uplevel> 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>, 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'>.
The constant L</SU_THREADSAFE> is also only exported on request, individually or by the tags C<':consts'> and C<':all'>.
reap
localize localize_elem localize_delete
unwind yield leave
- want_at
+ want_at context_info
uplevel
uid validate_uid
> ],
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>.
=head1 DEPENDENCIES
-L<perl> 5.6.
+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
=head1 COPYRIGHT & LICENSE
-Copyright 2008,2009,2010,2011,2012 Vincent Pit, all rights reserved.
+Copyright 2008,2009,2010,2011,2012,2013 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.
projects / perl / modules / Scope-Upper.git / blobdiff