Spidermonkey JS question

[I?igo Koch]

Hi,

I need to create an object that at the same time has a string value:

foo = "string1";
foo.bar = "string2";

It must be possible since browsers have a lot of these cases:
location = "str";
location.href = "str";
etc..

Thank you in advance for any light on this problem,

regards,

Iñigo Koch

[Lee]

Re: Spidermonkey JS question

I?igo Koch said:[color=blue]
>
>Hi,
>
>I need to create an object that at the same time has a string value:
>
>foo = "string1";
>foo.bar = "string2";
>
>It must be possible since browsers have a lot of these cases:
>location = "str";
>location.hre f = "str";
>etc..
>
>Thank you in advance for any light on this problem,[/color]

DOM objects have the advantage of being compiled into the
browser, so they can do some magic that the rest of us can't.

You can create your own toString() method for your object,
that can make it appear to have a different string value
than has been assigned to it. Maybe if you explain what it
is that you're trying to do, somebody can suggest a way to
do it.

[Brendan Eich]

Re: Spidermonkey JS question

I?igo Koch wrote:
[color=blue]
>Hi,
>
>I need to create an object that at the same time has a string value:
>
>foo = "string1";
>foo.bar = "string2";
>
>It must be possible since browsers have a lot of these cases:
>location = "str";
>location.hre f = "str";
>etc..
>
>[/color]

Mozilla uses a setter for window.location that can turn the string into
a URL, and internally do the equivalent of 'location.href = string'.
You can define a setter for an individual property when you define the
property, using JS_Define*Prope rty. You can also define a class
setProperty hook that special-cases based on id.

/be
[color=blue]
>Thank you in advance for any light on this problem,
>
>regards,
>
>Iñigo Koch
>
>[/color]

[Georg Maaß]

Re: Spidermonkey JS question

I?igo Koch wrote:[color=blue]
> Hi,
>
> I need to create an object that at the same time has a string value:
>
> foo = "string1";
> foo.bar = "string2";
>
> It must be possible since browsers have a lot of these cases:
> location = "str";
> location.href = "str";
> etc..[/color]

Only the first sample contains an implicite cast; the second does not.
The second sample uses a setter as written by Brendan. The first sample
first assigns a string value to the variable foo. foo now contains a
string value, not an object. foo.bar = "string2"; now casts foo
temporary to a String wrapper object. This is caused by the element
lookup operator. The string value "string2" is assigned to the bar
property of the temporary string object.

If you output foo you get "string1"; if you ouptut foo.bar, you get
undefined or nothing.

alert(foo + '\n' + foo.bar);

this alerts:

string1
undefined


js> print(foo + '\n' + foo.bar);

this writes:

string1



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