Tie::Array
Section: Perl Programmers Reference Guide (3)
Updated: perl 5.005, patch 02
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NAME
Tie::Array - base class for tied arrays
SYNOPSIS
package NewArray;
use Tie::Array;
@ISA = ('Tie::Array');
# mandatory methods
sub TIEARRAY { ... }
sub FETCH { ... }
sub FETCHSIZE { ... }
sub STORE { ... } # mandatory if elements writeable
sub STORESIZE { ... } # mandatory if elements can be added/deleted
# optional methods - for efficiency
sub CLEAR { ... }
sub PUSH { ... }
sub POP { ... }
sub SHIFT { ... }
sub UNSHIFT { ... }
sub SPLICE { ... }
sub EXTEND { ... }
sub DESTROY { ... }
package NewStdArray;
use Tie::Array;
@ISA = ('Tie::StdArray');
# all methods provided by default
package main;
$object = tie @somearray,Tie::NewArray;
$object = tie @somearray,Tie::StdArray;
$object = tie @somearray,Tie::NewStdArray;
DESCRIPTION
This module provides methods for array-tying classes. See
the perltie manpage for a list of the functions required in order to tie an array
to a package. The basic Tie::Array package provides stub DELETE
and EXTEND methods, and implementations of PUSH, POP, SHIFT,
UNSHIFT, SPLICE and CLEAR in terms of basic FETCH, STORE,
FETCHSIZE, STORESIZE.
The Tie::StdArray package provides efficient methods required for tied arrays
which are implemented as blessed references to an ``inner'' perl array.
It inherits from Tie::Array, and should cause tied arrays to behave exactly
like standard arrays, allowing for selective overloading of methods.
For developers wishing to write their own tied arrays, the required methods
are briefly defined below. See the the perltie manpage section for more detailed
descriptive, as well as example code:
- TIEARRAY classname, LIST
-
The class method is invoked by the command tie @array, classname. Associates
an array instance with the specified class. LIST would represent
additional arguments (along the lines of the AnyDBM_File manpage and compatriots) needed
to complete the association. The method should return an object of a class which
provides the methods below.
- STORE this, index, value
-
Store datum value into index for the tied array assoicated with
object this. If this makes the array larger then
class's mapping of undef should be returned for new positions.
- FETCH this, index
-
Retrieve the datum in index for the tied array assoicated with
object this.
- FETCHSIZE this
-
Returns the total number of items in the tied array assoicated with
object this. (Equivalent to scalar(@array)).
- STORESIZE this, count
-
Sets the total number of items in the tied array assoicated with
object this to be count. If this makes the array larger then
class's mapping of undef should be returned for new positions.
If the array becomes smaller then entries beyond count should be
deleted.
- EXTEND this, count
-
Informative call that array is likely to grow to have count entries.
Can be used to optimize allocation. This method need do nothing.
- CLEAR this
-
Clear (remove, delete, ...) all values from the tied array assoicated with
object this.
- DESTROY this
-
Normal object destructor method.
- PUSH this, LIST
-
Append elements of LIST to the array.
- POP this
-
Remove last element of the array and return it.
- SHIFT this
-
Remove the first element of the array (shifting other elements down)
and return it.
- UNSHIFT this, LIST
-
Insert LIST elements at the begining of the array, moving existing elements
up to make room.
- SPLICE this, offset, length, LIST
-
Perform the equivalent of splice on the array.
offset is optional and defaults to zero, negative values count back
from the end of the array.
length is optional and defaults to rest of the array.
LIST may be empty.
Returns a list of the original length elements at offset.
CAVEATS
There is no support at present for tied @ISA. There is a potential conflict
between magic entries needed to notice setting of @ISA, and those needed to
implement `tie'.
Very little consideration has been given to the behaviour of tied arrays
when $[ is not default value of zero.
AUTHOR
Nick Ing-Simmons <nik@tiuk.ti.com>
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- CAVEATS
-
- AUTHOR
-
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Time: 15:39:49 GMT, July 31, 2024