This is 0.23

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

diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm
index ac97d57cd360c8d38ec77ec8436b9c2697521d17..7553492c3bde6d88189582c33be7c70f34b70a7c 100644 (file)
--- a/lib/Scope/Upper.pm
+++ b/lib/Scope/Upper.pm
@@ -1,5 +1,7 @@
 package Scope::Upper;
 
 package Scope::Upper;
 

+use 5.006_001;
+

 use strict;
 use warnings;
 
 use strict;
 use warnings;
 


@@ -9,13 +11,13 @@ Scope::Upper - Act on upper scopes.
 
 =head1 VERSION
 
 
 =head1 VERSION
 

-Version 0.18
+Version 0.23

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

- $VERSION = '0.18';
+ $VERSION = '0.23';

 }
 
 =head1 SYNOPSIS
 }
 
 =head1 SYNOPSIS


@@ -170,7 +172,11 @@ localize variables, array/hash values or deletions of elements in higher context
 
 =item *
 
 
 =item *
 

-return values immediately to an upper level with L</unwind>, 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 *
 


@@ -178,7 +184,7 @@ execute a subroutine in the setting of an upper subroutine stack frame with L</u
 
 =item *
 
 
 =item *
 

-uniquely identify contextes with L</uid> and L</validate_uid>.
+uniquely identify contexts with L</uid> and L</validate_uid>.

 
 =back
 
 
 =back
 


@@ -270,7 +276,10 @@ C<$key> is either an array index or a hash key, depending of which kind of varia
 
 If C<$what> is a string pointing to an undeclared variable, the variable will be vivified as soon as the localization occurs and emptied when it ends, although it will still exist in its glob.
 
 
 If C<$what> is a string pointing to an undeclared variable, the variable will be vivified as soon as the localization occurs and emptied when it ends, although it will still exist in its glob.
 

-=head2 C<localize_delete $what, $key, $context>
+=head2 C<localize_delete>
+
+    localize_delete $what, $key;
+    localize_delete $what, $key, $context;

 
 Introduces the deletion of a variable or an array/hash element delayed to the time of first return into the upper scope denoted by C<$context>.
 C<$what> can be:
 
 Introduces the deletion of a variable or an array/hash element delayed to the time of first return into the upper scope denoted by C<$context>.
 C<$what> can be:


@@ -283,7 +292,7 @@ A glob, in which case C<$key> is ignored and the call is equivalent to C<local *
 
 =item *
 
 
 =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 *
 
 
 =item *
 


@@ -295,10 +304,11 @@ C<$key> is ignored.
 
 =head2 C<unwind>
 
 
 =head2 C<unwind>
 

-    unwind @values;
+    unwind;

     unwind @values, $context;
 
     unwind @values, $context;
 

-Returns C<@values> I<from> the context pointed by C<$context>, i.e. from the subroutine, eval or format at or just above C<$context>, and immediately restart the program flow at this point - thus effectively returning 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.
 This means that
 
 The upper context isn't coerced onto C<@values>, which is hence always evaluated in list context.
 This means that


@@ -312,14 +322,49 @@ This means that
 will set C<$num> to C<'z'>.
 You can use L</want_at> to handle these cases.
 
 will set C<$num> to C<'z'>.
 You can use L</want_at> to handle these cases.
 

+=head2 C<yield>
+
+    yield;
+    yield @values, $context;
+
+Returns C<@values> I<from> the context pointed by or just above C<$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.
+Hence you can use it to return values from a C<do> or a C<map> block :
+
+    my $now = do {
+     local $@;
+     eval { require Time::HiRes } or yield time() => HERE;
+     Time::HiRes::time();
+    };
+
+    my @uniq = map {
+     yield if $seen{$_}++; # returns the empty list from the block
+     ...
+    } @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;
+    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<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;
 
 =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');
 
     my $num = sub {
      my @a = ('a' .. 'z');


@@ -329,14 +374,72 @@ The previous example can then be "corrected" :
 
 will rightfully set C<$num> to C<26>.
 
 
 will rightfully set C<$num> to C<26>.
 

-=head2 C<uplevel $code, @args, $context>
+=head2 C<context_info>
+
+    my ($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 };
 
     my @ret = uplevel { ...; return @ret };

-    my @ret = uplevel { my @args = @_; ...; return @ret } @args;
-    my @ret = uplevel { ... } @args, $context;
+    my @ret = uplevel { my @args = @_; ...; return @ret } @args, $context;

     my @ret = &uplevel($callback, @args, $context);
 
     my @ret = &uplevel($callback, @args, $context);
 

-Executes the code reference C<$code> with arguments C<@args> as if it were located at the subroutine stack frame pointed by C<$context>, effectively fooling C<caller> and C<die> into believing that the call actually happened higher in the stack.
+Executes the code reference C<$callback> with arguments C<@args> as if it were located at the subroutine stack frame pointed by C<$context>, effectively fooling C<caller> and C<die> into believing that the call actually happened higher in the stack.

 The code is executed in the context of the C<uplevel> call, and what it returns is returned as-is by C<uplevel>.
 
     sub target {
 The code is executed in the context of the C<uplevel> call, and what it returns is returned as-is by C<uplevel>.
 
     sub target {


@@ -352,6 +455,8 @@ The code is executed in the context of the C<uplevel> call, and what it returns
     my @inverses = target(1, 2, 4); # @inverses contains (0, 0.5, 0.25)
     my $count    = target(1, 2, 4); # $count is 3
 
     my @inverses = target(1, 2, 4); # @inverses contains (0, 0.5, 0.25)
     my $count    = target(1, 2, 4); # $count is 3
 

+Note that if C<@args> is empty, then the C<$context> parameter is optional and defaults to the current context ; otherwise it is mandatory.
+

 L<Sub::Uplevel> also implements a pure-Perl version of C<uplevel>.
 Both are identical, with the following caveats :
 
 L<Sub::Uplevel> also implements a pure-Perl version of C<uplevel>.
 Both are identical, with the following caveats :
 


@@ -500,7 +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.
 =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>
 
 
 =head3 C<UP>
 


@@ -586,13 +691,14 @@ Where L</localize>, L</localize_elem> and L</localize_delete> act depending on t
     # $cxt = SCOPE(4), UP SUB UP SUB = UP SUB EVAL = UP CALLER(2) = TOP
     ...
 
     # $cxt = SCOPE(4), UP SUB UP SUB = UP SUB EVAL = UP CALLER(2) = TOP
     ...
 

-Where L</unwind>, 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 {
       sub {
        {
 
     sub {
      eval {
       sub {
        {

-        unwind @things => $cxt;   # or uplevel { ... } $cxt;
+        unwind @things => $cxt;   # or yield @things => $cxt
+                                  # or uplevel { ... } $cxt

         ...
        }
        ...
         ...
        }
        ...


@@ -608,7 +714,7 @@ Where L</unwind>, L</want_at> and L</uplevel> point to depending on the C<$cxt>:
 
 =head1 EXPORT
 
 
 =head1 EXPORT
 

-The functions L</reap>, L</localize>, L</localize_elem>, L</localize_delete>,  L</unwind>, 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'>.
 
 
 The constant L</SU_THREADSAFE> is also only exported on request, individually or by the tags C<':consts'> and C<':all'>.
 


@@ -623,7 +729,8 @@ our %EXPORT_TAGS = (
  funcs  => [ qw<
   reap
   localize localize_elem localize_delete
  funcs  => [ qw<
   reap
   localize localize_elem localize_delete

-  unwind want_at
+  unwind yield leave
+  want_at context_info

   uplevel
   uid validate_uid
  > ],
   uplevel
   uid validate_uid
  > ],


@@ -682,12 +789,17 @@ 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.
 
 
 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
 
 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<XSLoader> (standard since perl 5.006).
+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 5.6.0).

 
 =head1 SEE ALSO
 
 
 =head1 SEE ALSO
 


@@ -729,7 +841,7 @@ Thanks to Shawn M. Moore for motivation.
 
 =head1 COPYRIGHT & LICENSE
 
 
 =head1 COPYRIGHT & LICENSE
 

-Copyright 2008,2009,2010,2011 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.
 
 
 This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.