X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FScope%2FUpper.pm;h=acd566b0f7588a166d2cf460f3e7f1f76f33492b;hb=d965a45a64e2aab24e3adbda18543e80a0b81e57;hp=51cc4c48baad4535d26f83d48de2df56b3711b2b;hpb=ed73fd40f3dffe7fe72243300bec6efd83f3f2c8;p=perl%2Fmodules%2FScope-Upper.git diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm index 51cc4c4..acd566b 100644 --- a/lib/Scope/Upper.pm +++ b/lib/Scope/Upper.pm @@ -9,61 +9,89 @@ Scope::Upper - Act on upper scopes. =head1 VERSION -Version 0.10 +Version 0.13 =cut our $VERSION; BEGIN { - $VERSION = '0.10'; + $VERSION = '0.13'; } =head1 SYNOPSIS - package X; +L, L, L, L and L : + + package Scope; use Scope::Upper qw/reap localize localize_elem localize_delete :words/; - sub desc { shift->{desc} } + sub new { + my ($class, $name) = @_; + + localize '$tag' => bless({ name => $name }, $class) => UP; + + reap { print Scope->tag->name, ": end\n" } UP; + } - sub set_tag { - my ($desc) = @_; + # Get the tag stored in the caller namespace + sub tag { + my $l = 0; + my $pkg = __PACKAGE__; + $pkg = caller $l++ while $pkg eq __PACKAGE__; - # First localize $x so that it gets destroyed last - localize '$x' => bless({ desc => $desc }, __PACKAGE__) => UP; # one scope up + no strict 'refs'; + ${$pkg . '::tag'}; + } - reap sub { - my $pkg = caller; - my $x = do { no strict 'refs'; ${$pkg.'::x'} }; # Get the $x in the scope - print $x->desc . ": done\n"; - } => SCOPE 1; # same as UP here + sub name { shift->{name} } + # Locally capture warnings and reprint them with the name prefixed + sub catch { localize_elem '%SIG', '__WARN__' => sub { - my $pkg = caller; - my $x = do { no strict 'refs'; ${$pkg.'::x'} }; # Get the $x in the scope - CORE::warn($x->desc . ': ' . join('', @_)); - } => UP CALLER 0; # same as UP here + print Scope->tag->name, ': ', @_; + } => UP; + } - # delete last @ARGV element - localize_delete '@ARGV', -1 => UP SUB HERE; # same as UP here + # Locally clear @INC + sub private { + for (reverse 0 .. $#INC) { + # First UP is the for loop, second is the sub boundary + localize_delete '@INC', $_ => UP UP; + } } - package Y; + ... + + package UserLand; { - X::set_tag('pie'); - # $x is now a X object, and @ARGV has one element less - warn 'what'; # warns "pie: what at ..." - ... - } # "pie: done" is printed + Scope->new("top"); # initializes $UserLand::tag + + { + Scope->catch; + my $one = 1 + undef; # prints "top: Use of uninitialized value..." + + { + Scope->private; + eval { require Cwd }; + print $@; # prints "Can't locate Cwd.pm in @INC (@INC contains:) at..." + } + + require Cwd; # loads Cwd.pm + } + + } # prints "top: done" + +L and L : - package Z; + package Try; use Scope::Upper qw/unwind want_at :words/; sub try (&) { my @result = shift->(); - my $cx = SUB UP SUB; + my $cx = SUB UP; # Point to the sub above this one unwind +(want_at($cx) ? @result : scalar @result) => $cx; } @@ -71,13 +99,15 @@ BEGIN { sub zap { try { + my @things = qw/a b c/; return @things; # returns to try() and then outside zap() # not reached - } + }; # not reached } - my @what = zap(); # @what contains @things + my @stuff = zap(); # @stuff contains qw/a b c/ + my $stuff = zap(); # $stuff contains 3 =head1 DESCRIPTION @@ -117,11 +147,11 @@ BEGIN { =head2 C -Add a destructor that calls C<$callback> (in void context) when the upper scope represented by C<$context> ends. +Adds a destructor that calls C<$callback> (in void context) when the upper scope represented by C<$context> ends. =head2 C -A C delayed to the time of first return into the upper scope denoted by C<$context>. +Introduces a C delayed to the time of first return into the upper scope denoted by C<$context>. C<$what> can be : =over 4 @@ -143,24 +173,44 @@ For example, will set C<$x> to a reference to the string C<'foo'>. Other sigils (C<'@'>, C<'%'>, C<'&'> and C<'*'>) require C<$value> to be a reference of the corresponding type. -When the symbol is given by a string, it is resolved when the actual localization takes place and not when C is called. -This means that +When the symbol is given by a string, it is resolved when the actual localization takes place and not when L is called. +Thus, if the symbol name is not qualified, it will refer to the variable in the package where the localization actually takes place and not in the one where the L call was compiled. +For example, - sub tag { localize '$x', $_[0] => UP } + { + package Scope; + sub new { localize '$tag', $_[0] => UP } + } -will localize in the caller's namespace. + { + package Tool; + { + Scope->new; + ... + } + } + +will localize C<$Tool::tag> and not C<$Scope::tag>. +If you want the other behaviour, you just have to specify C<$what> as a glob or a qualified name. + +Note that if C<$what> is a string denoting a variable that wasn't declared beforehand, the relevant slot will be vivified as needed and won't be deleted from the glob when the localization ends. +This situation never arises with C because it only compiles when the localized variable is already declared. +Although I believe it shouldn't be a problem as glob slots definedness is pretty much an implementation detail, this behaviour may change in the future if proved harmful. =back =head2 C -Similar to L but for array and hash elements. -If C<$what> is a glob, the slot to fill is determined from which type of reference C<$value> is ; otherwise it's inferred from the sigil. +Introduces a C or C delayed to the time of first return into the upper scope denoted by C<$context>. +Unlike L, C<$what> must be a string and the type of localization is inferred from its sigil. +The two only valid types are array and hash ; for anything besides those, L will throw an exception. C<$key> is either an array index or a hash key, depending of which kind of variable you localize. +If C<$what> is a string pointing to an undeclared variable, the variable will be vivified as soon as the localization occurs and emptied when it ends, although it will still exist in its glob. + =head2 C -Similiar to L, but for deleting variables or array/hash elements. +Introduces the deletion of a variable or an array/hash element delayed to the time of first return into the upper scope denoted by C<$context>. C<$what> can be: =over 4 @@ -183,7 +233,7 @@ C<$key> is ignored. =head2 C -Returns C<@values> I 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. +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. The upper context isn't coerced onto C<@values>, which is hence always evaluated in list context. This means that @@ -199,7 +249,7 @@ You can use L to handle these cases. =head2 C -Like C, but for the subroutine/eval/format just above C<$context>. +Like C, but for the subroutine/eval/format at or just above C<$context>. The previous example can then be "corrected" : @@ -376,11 +426,15 @@ L (standard since perl 5.006). =head1 SEE ALSO +L, L. + L, L, L, L. L is a thin wrapper around L that gives you a continuation passing style interface to L. It's easier to use, but it requires you to have control over the scope where you want to return. +L. + =head1 AUTHOR Vincent Pit, C<< >>, L.