Murat Ünalan > Data-Type-0.02.02 > Data::Type::Tied

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NAME ^

Data::Type::Tied - bind variables to datatypes

DESCRIPTION ^

SYNOPSIS ^

  use Data::Type::Tied qw(:all);

  try
  {
    typ STD::ENUM( qw(DNA RNA) ), \( my $a, my $b );

    print "a is typ'ed" if istyp( $a );

    $a = 'DNA'; # $alias only accepts 'DNA' or 'RNA'
    $a = 'RNA';
    $a = 'xNA'; # throws exception

    untyp( $alias );
  }
  catch Data::Type::Exception with
  {
    printf "Expected '%s' %s at %s line %s\n", $e->value, $e->type->info, $e->file, $e->line;
  };

TYPE BINDING ^

A tie-interface for Data::Type's is introduced via typ(). Once a variable is typ'ed, valid() is called in the background for every fetch on the value.

FUNCTIONS

typ( $type, @ref_variables )

Once an invalid value was assigned to a typ'ed var an exception gets thrown, so place your code in a try+catch block to handle that correctly. To unglue a variable from its type use untyp() (see below). @ref_variables may be a list of references which suite to the $type used. Mostly its a reference to a scalar.

  try
  {
    typ EMAIL( 1 ), \( my $typed_var, my $typed_etc, .. );     # \( ... ) returns an array of references to its elements (perlreftut)

    $typed_var = 'john@doe.de'; # ok

    $typed_var = 'faked&fake.de'; # throws exception

  }
  ...

[Advanced Note] typ adds all references to a central registry and then ties them to Data::Type::Tied. So don't use tie directly, otherwise the other functions are confused and wont work.

$scalar = istyp( $type )

typ'd variables obscure themselfs, istyp() reveals $typed_var 's type. It does this via maintaining an internal registry of all typ'd varaibles.

        if( $what = istyp( $type ) )
        {
                print "variable \$type is tied to $what";
        }

[Note] It is a synonym to tied. See perltie.

untyp( $sref )

Takes the typ constrains from a variable (like untie).

        untyp( $sref );

[Note] It is nearly a synonym to untie, but also updates the internal registry.

EXPORT ^

None per default.

FUNCTIONS

':all' loads qw(typ untyp istyp).

CONTACT ^

Sourceforge http://sf.net/projects/datatype is hosting a project dedicated to this module. And I enjoy receiving your comments/suggestion/reports also via http://rt.cpan.org or http://testers.cpan.org.

AUTHOR ^

Murat Uenalan, <muenalan@cpan.org>

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