Using ( ) in ({ ...}) is mostly convention (ie. evaluate all inside { },
like you would with say x = (3 + (4 * 3)) ).
Getter and setter trigger specific behaviors when you try to get or set a
property. Try:
<html>
<script>
test = {
_memory: 0,
get memory() {
alert("memory is " + this._memory);
return this._memory;
},
set memory(value) {
var newValue = parseInt(value, 10);
this._memory = newValue * Math.random();
}
}
test.memory; //gets
test.memory = 52; //sets
test.memory; //gets
</script>
</html>
On 12/8/06, Cyril Concolato <[EMAIL PROTECTED]> wrote:
Hi Marcos,
Marcos Caceres a écrit :
Cyril raises an interesting point there regarding implementations and how
they should be handled by scripting langauges within the context of XBL. For
ECMAScript, it might be nice to write the constructor without using the old
({ ... }). Can I do the following?:
<implemenation>
//where "this" is the scope of this implementation
this.x = 1234;
this._y = 4321;
this.funky = function(){...}
this._helper = {( functionName: function() { return true; })}
</implemenation>
Exactly.
Regarding getters and setters, there is a reference and explanation as
part of the example (please see section 2.3 [1]).
Thanks Marcos. I had read the link but did not understand it. Actually,
the link [2] is more interesting than [1]. It describes the syntax
objectName = {property_1:value_1, property_2:value_2, ..., property_n:value_n}
which explains the use of ":".
Given that I still have two questions (not specifically related to XBL):
- why get and set do not use ':' ? I guess getter and setter are
particular properties and it's just a question of syntax
- what is the use of "(" in ({ ... }).
Regards,
Cyril
[2]
http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Guide:Creating_New_Objects:Using_Object_Initializers
Marcos
[1]
http://dev.w3.org/cvsweb/~checkout~/2006/xbl2/Overview.html#the-implementation<http://dev.w3.org/cvsweb/%7Echeckout%7E/2006/xbl2/Overview.html#the-implementation>
On 12/8/06, Cyril Concolato <[EMAIL PROTECTED] > wrote:
>
> Hi Marcos,
>
> Marcos Caceres a écrit :
> > Cyril,
> > That is standard notation for ECMAScript. Try it in your browser:
> > <html>
> > <script>
> > test = ({
> > functionName: function() {
> > alert("test");
> > }
> > })
> >
> > test.functionName();
> > </script>
> > </html>
> >
> > I think it is beyond the scope of the XBL spec to contain such
> > definitions. Please let us know if you are satisfied with this
> response.
> >
> Thanks for the answer. I did not know that notation. It must be some
> object-oriented syntax. I agree that XBL does not need to redefine
> ECMAScript syntax. The question is: Is the ECMAScript syntax in the
> 'implementation' element free like:
> <implementation>
> foo = 1;
> </implementation>
>
> or shall/should it obey some specific ECMAScript syntax (as all the
> examples in the specification suggest), i.e. start with ({, contain only
> fonction declarations, and end with }).
>
> If the syntax is free, please say so in the specification. If not,
> please give link to specifics constructs allowed from the ECMAScript
> specification. This would satisfy me.
>
> Regards,
>
> Cyril
> >
> > Regards,
> > Marcos
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto: [EMAIL PROTECTED] On Behalf Of Cyril
> Concolato
> > Sent: Thursday, 7 December 2006 2:01 AM
> > To: WAF WG (public)
> > Subject: [XBL] ECMAScript Syntax
> >
> >
> > Dear XBL experts,
> >
> > This email comments on the 7 September 2006 LCWD of XBL 2.0.
> >
> > In many examples in the specification, in particular in Section 2.3, a
> > syntax for ECMAScript definition of functions is used:
> >
> > <implementation>
> > ({
> > functionName: function() {
> > }
> > })
> > </implementation>
> >
> > Is this standard ECMAScript notation ? Could you explain it or provide
> a
> >
> > link to it ? What is the meaning of "({" ?
> > The get/set fonction in that section don't use the ':' ? Is it a typo
> ?
> > If yes please fix it, otherwise highlight and explain this difference
> > with the other functions.
> >
> > Cyril Concolato
> >
> >
> >
> >
> >
> >
>
>
--
Marcos Caceres
http://datadriven.com.au
--
Marcos Caceres
http://datadriven.com.au
