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functions and arguments.length; passing unknown number of arguments

 
 
oldyork90
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      09-24-2008
I'm going thru code and have never seen this before
http://www.webreference.com/programm...column2/3.html


Look at function CreateDragContainer() on line 25. It has no
arguments defined and depends on a function property named arguments
to process its input. I poked around and found this is deprecated.

How do you pass an unknown number of arguments to a function? Put
them in an array?

Thanks.
 
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Joost Diepenmaat
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      09-24-2008
oldyork90 <(E-Mail Removed)> writes:

> I'm going thru code and have never seen this before
> http://www.webreference.com/programm...column2/3.html
>
>
> Look at function CreateDragContainer() on line 25. It has no
> arguments defined and depends on a function property named arguments
> to process its input. I poked around and found this is deprecated.


Function.arguments is deprecated. The automically instantiated variable
arguments is not.

> How do you pass an unknown number of arguments to a function? Put
> them in an array?


I use the arguments variable.

--
Joost Diepenmaat | blog: http://joost.zeekat.nl/ | work: http://zeekat.nl/
 
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SAM
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      09-24-2008
Le 9/24/08 9:23 PM, oldyork90 a écrit :
>
> How do you pass an unknown number of arguments to a function? Put
> them in an array?


function hello() {
for(var i=0; i< arguments.length; i++) alert(arguments[i]);
}

hello('hello guy');
hello('hello','old boy');
hello('hello','Old Rock','the 90th');

var t1 = 'Hello';
var t2 = 'man';
hello(t1, t2);


Is there really necessary to put previously the arguments in an array ?


var or = ['hello','Old Rock','the 90th'];

function salut() {
arguments = arguments.length==1?
arguments[0].toString().split(',') : arguments;
for(var i=0; i< arguments.length; i++) alert(arguments[i]);
}

salut(or);

--
sm
 
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Kiran Makam
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      09-25-2008
On Sep 25, 12:23 am, oldyork90 <(E-Mail Removed)> wrote:

> How do you pass an unknown number of arguments to a function? Put
> them in an array?


You can use an object (with necessary properties initialized) to pass
the arguments.
For example, if your function requires 5 arguments: arg1, arg2...arg5

function myFn(oArgs){
var arg1 = oArgs.arg1;

//initialize if the arg is not passed
var arg2 = (oArgs.arg2 == undefined)? "myDefaultValue" : oArgs.arg2;
}

//function call
myFn(
{
arg1: "xxx",
arg2: "yyy",
...
arg5: "zzz"
}
);

- Kiran Makam

 
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Thomas 'PointedEars' Lahn
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      09-26-2008
Joost Diepenmaat wrote:
> Function.arguments is deprecated. The automically instantiated variable
> arguments is not.
>
>> How do you pass an unknown number of arguments to a function? Put
>> them in an array?

>
> I use the arguments variable.


`arguments' is a property of the Activation/Variable Object of a local
execution context, but not a variable. And no, that is not a contradiction


PointedEars
--
Prototype.js was written by people who don't know javascript for people
who don't know javascript. People who don't know javascript are not
the best source of advice on designing systems that use javascript.
-- Richard Cornford, cljs, <f806at$ail$1$(E-Mail Removed)>
 
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Joost Diepenmaat
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      09-26-2008
Thomas 'PointedEars' Lahn <(E-Mail Removed)> writes:

> Joost Diepenmaat wrote:
>> Function.arguments is deprecated. The automically instantiated variable
>> arguments is not.
>>
>>> How do you pass an unknown number of arguments to a function? Put
>>> them in an array?

>>
>> I use the arguments variable.

>
> `arguments' is a property of the Activation/Variable Object of a local
> execution context, but not a variable. And no, that is not a contradiction


In the interest of academics; is there any way to tell the difference
using javascript code?

--
Joost Diepenmaat | blog: http://joost.zeekat.nl/ | work: http://zeekat.nl/
 
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Thomas 'PointedEars' Lahn
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      09-26-2008
Joost Diepenmaat wrote:
> Thomas 'PointedEars' Lahn <(E-Mail Removed)> writes:
>> Joost Diepenmaat wrote:
>>> Function.arguments is deprecated. The automically instantiated variable
>>> arguments is not.
>>>
>>>> How do you pass an unknown number of arguments to a function? Put
>>>> them in an array?
>>> I use the arguments variable.

>> `arguments' is a property of the Activation/Variable Object of a local
>> execution context, but not a variable. And no, that is not a contradiction

>
> In the interest of academics; is there any way to tell the difference
> using javascript code?


Quick hack for testing if `x' was declared a local variable:

/\bvar\s+([A-Za-z_$][\w$]*\s*,\s*)*x\b/.test(arguments.callee)

This should be adapted for Unicode-aware implementations, see ES3F 12.2 and
7.5.3.


PointedEars
--
Prototype.js was written by people who don't know javascript for people
who don't know javascript. People who don't know javascript are not
the best source of advice on designing systems that use javascript.
-- Richard Cornford, cljs, <f806at$ail$1$(E-Mail Removed)>
 
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Thomas 'PointedEars' Lahn
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      09-26-2008
Thomas 'PointedEars' Lahn wrote:
> Quick hack for testing if `x' was declared a local variable:
>
> /\bvar\s+([A-Za-z_$][\w$]*\s*,\s*)*x\b/.test(arguments.callee)
>
> This should be adapted for Unicode-aware implementations, see ES3F 12.2 and
> 7.5.3.

^^^^^
I meant the following section, 7.6 ("Identifiers"), of course.

Thank you and good night


PointedEars
--
var bugRiddenCrashPronePieceOfJunk = (
navigator.userAgent.indexOf('MSIE 5') != -1
&& navigator.userAgent.indexOf('Mac') != -1
) // Plone, register_function.js:16
 
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Jorge
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      09-26-2008
On Sep 27, 1:12*am, Thomas 'PointedEars' Lahn <(E-Mail Removed)>
wrote:
> Joost Diepenmaat wrote:
> > Thomas 'PointedEars' Lahn <(E-Mail Removed)> writes:
> >> Joost Diepenmaat wrote:
> >>> Function.arguments is deprecated. The automically instantiated variable
> >>> arguments is not.

>
> >>>> How do you pass an unknown number of arguments to a function? *Put
> >>>> them in an array?
> >>> I use the arguments variable.
> >> `arguments' is a property of the Activation/Variable Object of a local
> >> execution context, but not a variable. *And no, that is not a contradiction

>
> > In the interest of academics; is there any way to tell the difference
> > using javascript code?

>
> Quick hack for testing if `x' was declared a local variable:
>
> * /\bvar\s+([A-Za-z_$][\w$]*\s*,\s*)*x\b/.test(arguments.callee)
>


Parsing the source ? come on ! That's not serious !

Try to see a bit further than your own nose. Activation objects are
notional entities. They could as well have called them 'magically
bound variables'.

--
Jorge.

 
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Thomas 'PointedEars' Lahn
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      09-27-2008
Jorge wrote:
> Thomas 'PointedEars' Lahn wrote:
>> Joost Diepenmaat wrote:
>>> Thomas 'PointedEars' Lahn <(E-Mail Removed)> writes:
>>>> Joost Diepenmaat wrote:
>>>>> Function.arguments is deprecated. The automically instantiated variable
>>>>> arguments is not.
>>>>>> How do you pass an unknown number of arguments to a function? Put
>>>>>> them in an array?
>>>>> I use the arguments variable.
>>>> `arguments' is a property of the Activation/Variable Object of a local
>>>> execution context, but not a variable. And no, that is not a contradiction
>>> In the interest of academics; is there any way to tell the difference
>>> using javascript code?

>> Quick hack for testing if `x' was declared a local variable:
>>
>> /\bvar\s+([A-Za-z_$][\w$]*\s*,\s*)*x\b/.test(arguments.callee)

>
> Parsing the source ? come on ! That's not serious !


If you have a better idea, then post it. If not, shut up.

> Try to see a bit further than your own nose. Activation objects are
> notional entities.


Whatever you might mean by "notional", Activation Objects exist and are part
of the scope chain of function code (ES3F, 10.2.3). Furthermore, "The
activation object is then used as the variable object for the purposes of
variable instantiation." (10.1.6) Unfortunately, the Activation/Variable
Object cannot be referred to, hence this quick hack.

> They could as well have called them 'magically bound variables'.


You could as well be called an incompetent fool, but I will assume in your
favor you are just tired or drunk or both right now. So go to bed, please.


PointedEars
--
Prototype.js was written by people who don't know javascript for people
who don't know javascript. People who don't know javascript are not
the best source of advice on designing systems that use javascript.
-- Richard Cornford, cljs, <f806at$ail$1$(E-Mail Removed)>
 
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