X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FScope%2FUpper.pm;h=b5936dbfa325253e1d2625c83205d71055c33cb7;hb=70187dc24bb0f90a81f58ff2bd52ba7d9c3ac06f;hp=6ef56c0b9da2dbebed800056b1a5fa8eb28dbe6c;hpb=c6e995c68b5384510061cde2d433e9506a3935f5;p=perl%2Fmodules%2FScope-Upper.git diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm index 6ef56c0..b5936db 100644 --- a/lib/Scope/Upper.pm +++ b/lib/Scope/Upper.pm @@ -9,13 +9,13 @@ Scope::Upper - Act on upper scopes. =head1 VERSION -Version 0.17 +Version 0.18 =cut our $VERSION; BEGIN { - $VERSION = '0.17'; + $VERSION = '0.18'; } =head1 SYNOPSIS @@ -24,7 +24,10 @@ L, L, L, L and L : package Scope; - use Scope::Upper qw; + use Scope::Upper qw< + reap localize localize_elem localize_delete + :words + >; sub new { my ($class, $name) = @_; @@ -66,22 +69,22 @@ L, L, L, L and L : package UserLand; { - Scope->new("top"); # initializes $UserLand::tag + Scope->new("top"); # initializes $UserLand::tag { Scope->catch; - my $one = 1 + undef; # prints "top: Use of uninitialized value..." + 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..." - } + print $@; # prints "Can't locate Cwd.pm in @INC + } # (@INC contains:) at..." - require Cwd; # loads Cwd.pm + require Cwd; # loads Cwd.pm } - } # prints "top: done" + } # prints "top: done" L and L : @@ -128,6 +131,28 @@ L : target('hello'); # "hello from Uplevel::target()" +L and L : + + use Scope::Upper qw; + + my $uid; + + { + $uid = uid(); + { + if ($uid eq uid(UP)) { # yes + ... + } + if (validate_uid($uid)) { # yes + ... + } + } + } + + if (validate_uid($uid)) { # no + ... + } + =head1 DESCRIPTION This module lets you defer actions I that will take place when the control flow returns into an upper scope. @@ -149,7 +174,11 @@ return values immediately to an upper level with L, and know which cont =item * -execute a subroutine in the setting of an upper subroutine stack frame with L. +execute a subroutine in the setting of an upper subroutine stack frame with L ; + +=item * + +uniquely identify contextes with L and L. =back @@ -353,6 +382,73 @@ 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 + +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. + + my $uid; + + { + $uid = uid; + if ($uid eq uid()) { # yes, this is the same context + ... + } + { + if ($uid eq uid()) { # no, we are one scope below + ... + } + if ($uid eq uid(UP)) { # yes, UP points to the same scope as $uid + ... + } + } + } + + # $uid is now invalid + + { + if ($uid eq uid()) { # no, this is another block + ... + } + } + +For example, each loop iteration gets its own UID : + + my %uids; + + for (1 .. 5) { + my $uid = uid; + $uids{$uid} = $_; + } + + # %uids has 5 entries + +The UIDs are not guaranteed to be numbers, so you must use the C operator to compare them. + +To check whether a given UID is valid, you can use the L function. + +=head2 C + +Returns true if and only if C<$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). + + my $uid; + + { + $uid = uid(); + if (validate_uid($uid)) { # yes + ... + } + { + if (validate_uid($uid)) { # yes + ... + } + } + } + + if (validate_uid($uid)) { # no + ... + } + =head1 CONSTANTS =head2 C @@ -414,13 +510,13 @@ Where L fires depending on the C<$cxt> : { reap \&cleanup => $cxt; ... - } # $cxt = SCOPE(0), or HERE + } # $cxt = SCOPE(0) = HERE ... - }->(); # $cxt = SCOPE(1), or UP, or SUB, or CALLER, or CALLER(0) + }->(); # $cxt = SCOPE(1) = UP = SUB = CALLER(0) ... - }; # $cxt = SCOPE(2), or UP UP, or UP SUB, or EVAL, or CALLER(1) + }; # $cxt = SCOPE(2) = UP UP = UP SUB = EVAL = CALLER(1) ... - }->(); # $cxt = SCOPE(3), or SUB UP SUB, or SUB EVAL, or CALLER(2) + }->(); # $cxt = SCOPE(3) = SUB UP SUB = SUB EVAL = CALLER(2) ... Where L, L and L act depending on the C<$cxt> : @@ -430,19 +526,19 @@ Where L, L and L act depending on t sub { { localize '$x' => 1 => $cxt; - # $cxt = SCOPE(0), or HERE + # $cxt = SCOPE(0) = HERE ... } - # $cxt = SCOPE(1), or UP, or SUB, or CALLER, or CALLER(0) + # $cxt = SCOPE(1) = UP = SUB = CALLER(0) ... }->(); - # $cxt = SCOPE(2), or UP UP, or UP SUB, or EVAL, or CALLER(1) + # $cxt = SCOPE(2) = UP UP = UP SUB = EVAL = CALLER(1) ... }; - # $cxt = SCOPE(3), or SUB UP SUB, or SUB EVAL, or CALLER(2) + # $cxt = SCOPE(3) = SUB UP SUB = SUB EVAL = CALLER(2) ... }->(); - # $cxt = SCOPE(4), UP SUB UP SUB, or UP SUB EVAL, or UP CALLER(2), or TOP + # $cxt = SCOPE(4), UP SUB UP SUB = UP SUB EVAL = UP CALLER(2) = TOP ... Where L, L and L point to depending on the C<$cxt>: @@ -451,15 +547,15 @@ Where L, L and L point to depending on the C<$cxt>: eval { sub { { - unwind @things => $cxt; # or uplevel { ... } $cxt; + unwind @things => $cxt; # or uplevel { ... } $cxt; ... } ... - }->(); # $cxt = SCOPE(0 .. 1), or HERE, or UP, or SUB, or CALLER(0) + }->(); # $cxt = SCOPE(0) = SCOPE(1) = HERE = UP = SUB = CALLER(0) ... - }; # $cxt = SCOPE(2), or UP UP, or UP SUB, or EVAL, or CALLER(1) (*) + }; # $cxt = SCOPE(2) = UP UP = UP SUB = EVAL = CALLER(1) (*) ... - }->(); # $cxt = SCOPE(3), or SUB UP SUB, or SUB EVAL, or CALLER(2) + }->(); # $cxt = SCOPE(3) = SUB UP SUB = SUB EVAL = CALLER(2) ... # (*) Note that uplevel() will croak if you pass that scope frame, @@ -484,6 +580,7 @@ our %EXPORT_TAGS = ( localize localize_elem localize_delete unwind want_at uplevel + uid validate_uid > ], words => [ qw ], consts => [ qw ],