| Name : perl-Lexical-Persistence
| |
| Version : 1.023
| Vendor : obs://build_opensuse_org/devel:languages:perl
|
| Release : 18.1
| Date : 2016-04-30 14:03:43
|
| Group : Development/Libraries/Perl
| Source RPM : perl-Lexical-Persistence-1.023-18.1.src.rpm
|
| Size : 0.07 MB
| |
| Packager : (none)
| |
| Summary : Persistent lexical variable values for arbitrary calls.
|
Description :
Lexical::Persistence does a few things, all related. Note that all the
behaviors listed here are the defaults. Subclasses can override nearly
every aspect of Lexical::Persistence\'s behavior.
Lexical::Persistence lets your code access persistent data through lexical
variables. This example prints \"some value\" because the value of $x
persists in the $lp object between setter() and getter().
use Lexical::Persistence;
my $lp = Lexical::Persistence->new();
$lp->call(\\&setter);
$lp->call(\\&getter);
sub setter { my $x = \"some value\" }
sub getter { print my $x, \"\
\" }
Lexicals with leading underscores are not persistent.
By default, Lexical::Persistence supports accessing data from multiple
sources through the use of variable prefixes. The set_context() member sets
each data source. It takes a prefix name and a hash of key/value pairs. By
default, the keys must have sigils representing their variable types.
use Lexical::Persistence;
my $lp = Lexical::Persistence->new();
$lp->set_context( pi => { \'$member\' => 3.141 } );
$lp->set_context( e => { \'AATTmember\' => [ 2, \'.\', 7, 1, 8 ] } );
$lp->set_context(
animal => {
\'%member\' => { cat => \"meow\", dog => \"woof\" }
}
);
$lp->call(\\&display);
sub display {
my ($pi_member, AATTe_member, %animal_member);
print \"pi = $pi_member\
\";
print \"e = AATTe_member\
\";
while (my ($animal, $sound) = each %animal_member) {
print \"The $animal goes... $sound!\
\";
}
}
And the corresponding output:
pi = 3.141
e = 2 . 7 1 8
The cat goes... meow!
The dog goes... woof!
By default, call() takes a single subroutine reference and an optional list
of named arguments. The arguments will be passed directly to the called
subroutine, but Lexical::Persistence also makes the values available from
the \"arg\" prefix.
use Lexical::Persistence;
my %animals = (
snake => \"hiss\",
plane => \"I\'m Cartesian\",
);
my $lp = Lexical::Persistence->new();
while (my ($animal, $sound) = each %animals) {
$lp->call(\\&display, animal => $animal, sound => $sound);
}
sub display {
my ($arg_animal, $arg_sound);
print \"The $arg_animal goes... $arg_sound!\
\";
}
And the corresponding output:
The plane goes... I\'m Cartesian!
The snake goes... hiss!
Sometimes you want to call functions normally. The wrap() method will wrap
your function in a small thunk that does the call() for you, returning a
coderef.
use Lexical::Persistence;
my $lp = Lexical::Persistence->new();
my $thunk = $lp->wrap(\\&display);
$thunk->(animal => \"squirrel\", sound => \"nuts\");
sub display {
my ($arg_animal, $arg_sound);
print \"The $arg_animal goes... $arg_sound!\
\";
}
And the corresponding output:
The squirrel goes... nuts!
Prefixes are the characters leading up to the first underscore in a lexical
variable\'s name. However, there\'s also a default context named underscore.
It\'s literally \"_\" because the underscore is not legal in a context name by
default. Variables without prefixes, or with prefixes that have not been
previously defined by set_context(), are stored in that context.
The get_context() member returns a hash for a named context. This allows
your code to manipulate the values within a persistent context.
use Lexical::Persistence;
my $lp = Lexical::Persistence->new();
$lp->set_context(
_ => {
\'AATTmind\' => [qw(My mind is going. I can feel it.)]
}
);
while (1) {
$lp->call(\\&display);
my $mind = $lp->get_context(\"_\")->{\'AATTmind\'};
splice AATT$mind, rand(AATT$mind), 1;
last unless AATT$mind;
}
sub display {
my AATTmind;
print \"AATTmind\
\";
}
Displays something like:
My mind is going. I can feel it.
My is going. I can feel it.
My is going. I feel it.
My going. I feel it.
My going. I feel
My I feel
My I
My
It\'s possible to create multiple Lexical::Persistence objects, each with a
unique state.
use Lexical::Persistence;
my $lp_1 = Lexical::Persistence->new();
$lp_1->set_context( _ => { \'$foo\' => \"context 1\'s foo\" } );
my $lp_2 = Lexical::Persistence->new();
$lp_2->set_context( _ => { \'$foo\' => \"the foo in context 2\" } );
$lp_1->call(\\&display);
$lp_2->call(\\&display);
sub display {
print my $foo, \"\
\";
}
Gets you this output:
context 1\'s foo
the foo in context 2
You can also compile and execute perl code contained in plain strings in a
a lexical environment that already contains the persisted variables.
use Lexical::Persistence;
my $lp = Lexical::Persistence->new();
$lp->do( \'my $message = \"Hello, world\" );
$lp->do( \'print \"$message\
\"\' );
Which gives the output:
Hello, world
If you come up with other fun uses, let us know.
|
RPM found in directory: /packages/linux-pbone/ftp5.gwdg.de/pub/opensuse/repositories/devel:/languages:/perl/SLE_12_SP1/noarch |
Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server
Provides :
perl(Lexical::Persistence)
perl-Lexical-Persistence
Requires :
