X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FScope%2FUpper.pm;h=ac254177da01cc448839ab2d38c3f6a8fcb5bd20;hb=1cac52223ba0983d5d4007ab608fe4ea645eb037;hp=b5936dbfa325253e1d2625c83205d71055c33cb7;hpb=70187dc24bb0f90a81f58ff2bd52ba7d9c3ac06f;p=perl%2Fmodules%2FScope-Upper.git diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm index b5936db..ac25417 100644 --- a/lib/Scope/Upper.pm +++ b/lib/Scope/Upper.pm @@ -9,13 +9,13 @@ Scope::Upper - Act on upper scopes. =head1 VERSION -Version 0.18 +Version 0.19 =cut our $VERSION; BEGIN { - $VERSION = '0.18'; + $VERSION = '0.19'; } =head1 SYNOPSIS @@ -170,7 +170,7 @@ localize variables, array/hash values or deletions of elements in higher context =item * -return values immediately to an upper level with L, and know which context was in use then with L ; +return values immediately to an upper level with L and L, and know which context was in use then with L ; =item * @@ -197,11 +197,18 @@ BEGIN { XSLoader::load(__PACKAGE__, $VERSION); } -=head2 C +=head2 C + + reap { ... }; + reap { ... } $context; + &reap($callback, $context); Adds a destructor that calls C<$callback> (in void context) when the upper scope represented by C<$context> ends. -=head2 C +=head2 C + + localize $what, $value; + localize $what, $value, $context; Introduces a C delayed to the time of first return into the upper scope denoted by C<$context>. C<$what> can be : @@ -251,7 +258,10 @@ Although I believe it shouldn't be a problem as glob slots definedness is pretty =back -=head2 C +=head2 C + + localize_elem $what, $key, $value; + localize_elem $what, $key, $value, $context; Introduces a C or C delayed to the time of first return into the upper scope denoted by C<$context>. Unlike L, C<$what> must be a string and the type of localization is inferred from its sigil. @@ -260,7 +270,10 @@ C<$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. -=head2 C +=head2 C + + 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<$what> can be: @@ -283,9 +296,13 @@ C<$key> is ignored. =back -=head2 C +=head2 C -Returns C<@values> I 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. + unwind; + unwind @values, $context; + +Returns C<@values> I the subroutine, eval or format context pointed by or just above C<$context>, and immediately restart the program flow at this point - thus effectively returning C<@values> to an upper scope. +If C<@values> is empty, then the C<$context> parameter is optional and defaults to the current context (making the call equivalent to a bare C) ; otherwise it is mandatory. The upper context isn't coerced onto C<@values>, which is hence always evaluated in list context. This means that @@ -299,7 +316,34 @@ This means that will set C<$num> to C<'z'>. You can use L to handle these cases. -=head2 C +=head2 C + + yield; + yield @values, $context; + +Returns C<@values> I the context pointed by or just above C<$context>, and immediately restart 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 differs from L in that it can target I upper scope (besides a C substitution context) and not necessarily a sub, an eval or a format. +Hence you can use it to return values from a C or a C 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, the upper context isn't coerced onto C<@values>. + +=head2 C + + my $want = want_at; + my $want = want_at $context; Like C, but for the subroutine/eval/format at or just above C<$context>. @@ -313,9 +357,13 @@ The previous example can then be "corrected" : will rightfully set C<$num> to C<26>. -=head2 C +=head2 C -Executes the code reference C<$code> with arguments C<@args> as if it were located at the subroutine stack frame pointed by C<$context>, effectively fooling C and C into believing that the call actually happened higher in the stack. + my @ret = uplevel { ...; return @ret }; + my @ret = uplevel { my @args = @_; ...; return @ret } @args, $context; + my @ret = &uplevel($callback, @args, $context); + +Executes the code reference C<$callback> with arguments C<@args> as if it were located at the subroutine stack frame pointed by C<$context>, effectively fooling C and C into believing that the call actually happened higher in the stack. The code is executed in the context of the C call, and what it returns is returned as-is by C. sub target { @@ -331,6 +379,8 @@ The code is executed in the context of the C call, and what it returns my @inverses = target(1, 2, 4); # @inverses contains (0, 0.5, 0.25) my $count = target(1, 2, 4); # $count is 3 +Note that if C<@args> is empty, then the C<$context> parameter is optional and defaults to the current context ; otherwise it is mandatory. + L also implements a pure-Perl version of C. Both are identical, with the following caveats : @@ -382,7 +432,10 @@ 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 +=head2 C + + my $uid = uid; + my $uid = uid $context; Returns an unique identifier (UID) for the context (or dynamic scope) pointed by C<$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. @@ -427,7 +480,9 @@ The UIDs are not guaranteed to be numbers, so you must use the C operator to To check whether a given UID is valid, you can use the L function. -=head2 C +=head2 C + + my $is_valid = validate_uid $uid; Returns true if and only if C<$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). @@ -461,10 +516,14 @@ True iff the module could have been built when thread-safety features. =head3 C + my $top_context = TOP; + Returns the context that currently represents the highest scope. =head3 C + my $current_context = HERE; + The context of the current scope. =head2 Getting a context from a context @@ -472,16 +531,25 @@ The context of the current scope. For any of those functions, C<$from> is expected to be a context. When omitted, it defaults to the the current context. -=head3 C +=head3 C + + my $upper_context = UP; + my $upper_context = UP $from; The context of the scope just above C<$from>. -=head3 C +=head3 C + + my $sub_context = SUB; + 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. -=head3 C +=head3 C + + my $eval_context = EVAL; + my $eval_context = EVAL $from; The context of the closest eval above C<$from>. Note that C<$from> is returned if it is already an eval context ; hence C. @@ -491,11 +559,17 @@ Note that C<$from> is returned if it is already an eval context ; hence C should denote a number of scopes above the current one. When omitted, it defaults to C<0> and those functions return the same context as L. -=head3 C +=head3 C + + my $context = SCOPE; + my $context = SCOPE $level; The C<$level>-th upper context, regardless of its type. -=head3 C +=head3 C + + my $context = CALLER; + my $context = CALLER $level; The context of the C<$level>-th upper subroutine/eval/format. It kind of corresponds to the context represented by C, but while e.g. C refers to the caller context, C will refer to the top scope in the current context. @@ -541,13 +615,14 @@ Where L, L and L act depending on t # $cxt = SCOPE(4), UP SUB UP SUB = UP SUB EVAL = UP CALLER(2) = TOP ... -Where L, L and L point to depending on the C<$cxt>: +Where L, L, L and L point to depending on the C<$cxt>: sub { eval { sub { { - unwind @things => $cxt; # or uplevel { ... } $cxt; + unwind @things => $cxt; # or yield @things => $cxt + # or uplevel { ... } $cxt ... } ... @@ -563,7 +638,7 @@ Where L, L and L point to depending on the C<$cxt>: =head1 EXPORT -The functions L, L, L, L, L, L and L are only exported on request, either individually or by the tags C<':funcs'> and C<':all'>. +The functions L, L, L, L, L, L, L and L are only exported on request, either individually or by the tags C<':funcs'> and C<':all'>. The constant L is also only exported on request, individually or by the tags C<':consts'> and C<':all'>. @@ -578,7 +653,8 @@ our %EXPORT_TAGS = ( funcs => [ qw< reap localize localize_elem localize_delete - unwind want_at + unwind yield + want_at uplevel uid validate_uid > ], @@ -684,7 +760,7 @@ Thanks to Shawn M. Moore for motivation. =head1 COPYRIGHT & LICENSE -Copyright 2008,2009,2010,2011 Vincent Pit, all rights reserved. +Copyright 2008,2009,2010,2011,2012 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.