Tie::Array

See the current Perl documentation for Tie::Array.

Here is our local, out-dated (pre-5.6) version:

Tie::Array - base class for tied arrays

    package NewArray;
    use Tie::Array;
    @ISA = ('Tie::Array');
                       
    # mandatory methods
    sub TIEARRAY { ... }  
    sub FETCH { ... }     
    sub FETCHSIZE { ... } 
        
    sub STORE { ... }        # mandato
    

    

This module provides methods for array-tying classes. See
perltie 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 perlguts 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 perltie 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 AnyDBM_File 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).

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>