---
name: "Tie::Array"
section: "3pm"
platform: "linux"
package: "perl-5.005-doc"
version: "5.005.03-7.1"
release: "Debian 2.2 (Potato)"
platforms: ["linux"]
url: "https://new.carta.tech/Tie::Array/3pm"
---

# Tie::Array(3pm)

base class for tied arrays

## 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 associated 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 associated with object *this*.\

- FETCHSIZE this

  Returns the total number of items in the tied array associated with object *this*. (Equivalent to `scalar(@array)`).\

- STORESIZE this, count

  Sets the total number of items in the tied array associated 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 associated 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 beginning 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\>