Array.pdf

(28 KB) Pobierz
Perl version 5.10.0 documentation - Tie::Array
NAME
Tie::Array - base class for tied arrays
SYNOPSIS
package Tie::NewArray;
use Tie::Array;
@ISA = ('Tie::Array');
# mandatory methods
sub TIEARRAY { ... }
sub FETCH { ... }
sub FETCHSIZE { ... }
sub
sub
sub
sub
STORE { ... }
STORESIZE { ... }
EXISTS { ... }
DELETE { ... }
#
#
#
#
mandatory
mandatory
mandatory
mandatory
if
if
if
if
elements
elements
exists()
delete()
writeable
can be added/deleted
expected to work
expected to work
# optional methods - for efficiency
sub CLEAR { ... }
sub PUSH { ... }
sub POP { ... }
sub SHIFT { ... }
sub UNSHIFT { ... }
sub SPLICE { ... }
sub EXTEND { ... }
sub DESTROY { ... }
package Tie::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
perltie
for a list of the functions required in
order to tie an array to a package. The basic
Tie::Array
package provides stub
DESTROY,
and
EXTEND
methods that do nothing, stub
DELETE
and
EXISTS
methods that croak() if the delete() or
exists() builtins are ever called on the tied array, 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.
http://perldoc.perl.org
Page 1
Perl version 5.10.0 documentation - Tie::Array
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 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.
EXISTS this, key
Verify that the element at index
key
exists in the tied array
this.
The
Tie::Array
implementation is a stub that simply croaks.
DELETE this, key
Delete the element at index
key
from the tied array
this.
The
Tie::Array
implementation is a stub that simply croaks.
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.
http://perldoc.perl.org
Page 2
Perl version 5.10.0 documentation - Tie::Array
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>
http://perldoc.perl.org
Page 3

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin