HTMLPurifier_Zipper Class Reference

Public Member Functions
	__construct ($front, $back)
	toArray ($t=NULL)
	next ($t)
	advance ($t, $n)
	prev ($t)
	delete ()
	done ()
	insertBefore ($t)
	insertAfter ($t)
	splice ($t, $delete, $replacement)

Static Public Member Functions
static	fromArray ($array)

Data Fields
	$front
	$back

Detailed Description

A zipper is a purely-functional data structure which contains a focus that can be efficiently manipulated. It is known as a "one-hole context". This mutable variant implements a zipper for a list as a pair of two arrays, laid out as follows:

 Base list: 1 2 3 4 [ ] 6 7 8 9
 Front list: 1 2 3 4
 Back list: 9 8 7 6

User is expected to keep track of the "current element" and properly fill it back in as necessary. (ToDo: Maybe it's more user friendly to implicitly track the current element?)

Nota bene: the current class gets confused if you try to store NULLs in the list.

Constructor & Destructor Documentation

__construct()

__construct	(		$front,
			$back
	)

Member Function Documentation

advance()

advance	(		$t,
			$n
	)

Iterated hole advancement.

Parameters

$t	Element to fill hole with
$i	How many forward to advance hole

Returns

Original contents of new hole, i away

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delete()

delete

(

)

Delete contents of current hole, shifting hole to next element.

Returns

Original contents of new hole.

done()

done

(

)

Returns true if we are at the end of the list.

Returns

bool

fromArray()

static fromArray (   $array )

static

Creates a zipper from an array, with a hole in the 0-index position.

Parameters

Array

to zipper-ify.

Returns

Tuple of zipper and element of first position.

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insertAfter()

insertAfter

(

$t

)

Insert element after hole.

Parameters

Element

to insert

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insertBefore()

insertBefore

(

$t

)

Insert element before hole.

Parameters

Element

to insert

next()

next

(

$t

)

Move hole to the next element.

Parameters

$t	Element to fill hole with

Returns

Original contents of new hole.

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prev()

prev

(

$t

)

Move hole to the previous element

Parameters

$t	Element to fill hole with

Returns

Original contents of new hole.

splice()

splice	(		$t,
			$delete,
			$replacement
	)

Splice in multiple elements at hole. Functional specification in terms of array_splice:

 $arr1 = $arr;
 $old1 = array_splice($arr1, $i, $delete, $replacement);

 list($z, $t) = HTMLPurifier_Zipper::fromArray($arr);
 $t = $z->advance($t, $i);
 list($old2, $t) = $z->splice($t, $delete, $replacement);
 $arr2 = $z->toArray($t);

 assert($old1 === $old2);
 assert($arr1 === $arr2);

NB: the absolute index location after this operation is unchanged!

Parameters

Current

contents of hole.

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toArray()

toArray

(

$t = NULL

)

Convert zipper back into a normal array, optionally filling in the hole with a value. (Usually you should supply a $t, unless you are at the end of the array.)

Field Documentation

$back

$back

$front

$front

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The documentation for this class was generated from the following file:

• C:/xoops2511b2/htdocs/xoops_lib/modules/protector/library/HTMLPurifier/Zipper.php