277429 - javascript: loosing all methods of inherited native objects

Status: RESOLVED INVALID

(SeaMonkey :: General, defect)

Description

[Heinz Kohl]

e.g.: 
function Table(row,col) {
  this.base = Array; // Date
  this.base(col);
  ....
the resulting constructor Table has no Array (Date,..) specific method, e.g. no
length

Comment 1

[Heinz Kohl]

Attachment: html file, inheriting from Array and Date

Comment 2

[Bob Clary [:bc] (inactive)]

You are not inheriting from the Date, Array Objects properly. You might find
<http://bclary.com/2004/09/26/boot-camp-javascript#Introduction_to_Objects> helpful.

-> INVALID

Comment 3

[Heinz Kohl]

thanks for the "bclary" reference! not uncommented wrong/misleading examples,
but a glance of an understandable concept; additionally an answer to getters and
setters ("deprecated/recommended"),
and no more surprises to expect like output of { [native code] } for
xy.toSource() for a self written xy and loosing getters

Comment 4

[Heinz Kohl]

> Which examples did you find incorrect or inadequately commented?

Not yours!!!
Sorry, maybe I've taken wrong words.

Some months ago, I'd had found some javascript examples, e.g. belonging to SVG
use (mostly Mozilla SVG), or valuable documents like XFLY.
I don't know exactly where, but in one or some of these papers I've found the
deprecated/wrong/old methods, which I'd used - I didn't find better information
for the state of art until your paper

Comment 5

[Heinz Kohl]

I've found the cause of my usage of 
  this.base = Constructor; this.base(...)
This is, as I see after reading the document given in the answer, of course a
strange idea, Constructor.call or .apply don't create the unnecessary
"this.base" or even an additional "this.base2".
And I've read the passage "You need still to explicitely set up the prototype to
ensure dynamic inheritance" in the same paper as "when you are needing only
static inheritance, this is not necessary".
Source of this misleading hints is the "Core JavaScript Guide 1.5" from
Netscape, last update 28.9.2000

The standard constructors for Mozilla, called in that manner, are indeed not
working as I'd expected. There are also some restrictions due to then syntax,
but arrays may indeed be inherited and a part of the expected implications of
inherited arrays - partly masking of arrays! - is working (to be used with
caution because of the potential of language changes).
An example beside of the use of sparse matrices:

// masking a line of a projection matrix ... 
function Projection(mask) { // mask: 0 .. x, 1 .. y, 2 .. z
  if (mask) this[mask] = [0,0,0,0];
  this.project = affine;
}

Projection.prototype = new Array;

Projection.prototype[0] = [ 1,0,0,0 ];
Projection.prototype[1] = [ 0,0,1,0 ], 
Projection.prototype[2] = [ 0,1,0,0 ], 
Projection.prototype[3] = [ 0,0,0,1 ];

Projection.prototype.name   = "Projection";
// for (var ee= 0; ee < 7; ee++) Projection.prototype[ee] = ee * Math.sin(ee);
// dynamically changeable