Name: _position, current(), next(), previous() a constant reference for a position in an array
Author: senocular: www.senocular.com
Date: 1899-12-31T00:42:55.600
Documentation:
Array _POSITION: A property and a group of
methods for array objects which allow you to walk or
cycle through an array given its _position within
that array. Every array's _position starts at 0 and
can be changed at any time either manually or through using
the next() or previous() methods, both of which, as is
also true with current, retrieves/sets that _position in
the array, with next() and previous() also moving it.
myArray._position
- array property referencing the current position of an array objects... position.
myArray.current(newValue);
myArray.next(newValue);
myArray.previous(newValue);
Arguments:
- newValue: (optional) a new value to be placed in the desired position of the array.
For current() the array index is myArray._position. For next, its myArray._position+1 and
for previous() its myArray._position-1 - this, however, unless the index surpasses the
bounds of the array, at which point the _position is placed on the other side of the
array, ie. 0 for next if it goes beyond the length of the array and myArray.length-1
for previous() in case _postion goes below 0.
Returns:
- returns the element currently existing at that array position. If a new Value is added,
the old value is returned.
next() moves the _position of the array to the next element
previous() moves the _position of the array to the previous element
Example:
// cycle through an array with length 10 adding
// the time which the mouse was clicked using
// getTimer(). once the end is reached, the
// _position is back to 0 and it repeats the
// cycle starting with the 'front' of the array
clickArray = new Array(10);
clickArray.current(getTimer());
this.onMouseDown = function(){
clickArray.previous(getTimer());
trace("["+clickArray+"]");
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Array.prototype._position = 0;
Array.prototype.current = function(newVal){
if (!this.length) return undefined;
if (!this._position) this._position = 0;
else if (this._position >= this.length) this._position = this.length-1;
if (newVal == undefined) return this[this._position];
var orig = this[this._position];
this[this._position] = newVal;
return orig;
};
Array.prototype.next = function(newVal){
if (!this.length) return undefined;
if (this._position <= 0) this._position = 1;
else if (this._position >= this.length-1) this._position = 0;
else ++this._position;
if (newVal == undefined) return this[this._position];
var orig = this[this._position];
this[this._position] = newVal;
return orig;
};
Array.prototype.previous = function(newVal){
if (!this.length) return undefined;
if (this._position <= 0 || this._position >= this.length) this._position = this.length-1
else --this._position;
if (newVal == undefined) return this[this._position];
var orig = this[this._position];
this[this._position] = newVal;
return orig;
};
