Re: [iSVG] Checking for the style interface

[Robin B. <ro...@kn...>]

On Tuesday 18 September 2001 19:58, Antoine Quint wrote:
> node_list.item(i).hasOwnProperty('style') works great! Where did you
> find info about this?

The E262 is a PITA to read (it's targetted towards implementors) but it's the 
total spec, and contains everything.

From what I understand, OO in E262 is completely prototype based. That is, a 
random string has the prototype of String, etc... Now you have this thing 
that is called the Object object, from which all other objects derive (I 
still haven't figured out how that derivation works, but perhaps someone here 
is expert enough in type-based oo to explain it kindly to me).

Object has the hasOwnProperty method which is there to check for the presence 
of a property (what you get through accessors like getFoo()). So I guessed 
that it had to be available to all objects.

> Also, this example:
>
> var props = '';
> for (p in element) {
>     props += p + ': ' + element[p] + "\n";
> }
> alert(props);
>
> Looks great but I don't understand what it does, where is p coming from?

This is a much more classical usage of E262. The 'in' is key here, it's an 
iterator over 'element''s properties. For every iteration, p is simply the 
name of the next property (which likely includes methods, as methods in E262 
are simply executable properties). In turn, element[p] is the value 
corresponding to that property.

You can also do that in your browser, I often use it to debug weird 
behaviours.

Hey, it looks like I might be becoming an E262 expert. S**t, I hope news of 
that don't spread to the Perl community or I might just as well switch to 
Python as well ;-)

-- 
_______________________________________________________________________
Robin Berjon <ro...@kn...> -- CTO
k n o w s c a p e : // venture knowledge agency www.knowscape.com
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