[parenscript-devel] How to generate element[i].childNodes[0].nodeValue

[Red Daly]

On Tue, Dec 1, 2009 at 4:10 PM, Vladimir Sedach <vsedach at gmail.com> wrote:
>> I disagree with that characterization of SLOT-VALUE, since it is very
>> similar to SLOT-VALUE in lisp but the slots have different semantics
>> (MOP semantics in Lisp and hash-map semantics in Javascript).
>
> The bigger problem is that now PS SLOT-VALUE has a completely
> different argument signature from the CL one, and people will use
> that. So there's no way to get PS code that uses it to work in CL, and
> it also conflicts if you want to implement CLOS in PS (I imagine this
> might be a problem for PSOS).

Good point.  I did not put in fancy slot semantics for PSOS because I
was concerned about speed (and I did not need them).  I also do not
share code between between CL and Parenscript so I haven't run into
the former problem.  Nonetheless this is an important objection to
using slot-value.

Red

>
>> We
>> should also note that this will break a lot of code, which generated
>> some criticism with the last Parenscript release.
>
> Yes, I put SLOT-VALUE in the deprecated interface list, which will
> issue a warning. This isn't an incompatible change, good thing for
> everybody.
>
>> Not that it's a big deal to rename things, and PROPERTY-VALUE is a
>> good alternative.  I suppose because of the simpler semantics of the
>> object system in Javascript that even calling it PROPERTY, as
>> suggested, is not ambiguous.  (If it were Lisp, SLOT could designate
>> the slot metaobject as opposed to the slot value for a given
>> instance).
>
> Since the JS terminology calls object slots properties, it definitely
> makes sense to call the accessor something to do with "property." The
> three choices so var are GET-PROPERTY, PROPERTY, and PROPERTY-VALUE. I
> like GET-PROPERTY because it has a similar convention to GETHASH and
> GETF. On the other hand, if it were really similar, it might be called
> GETPROP. There's something ambiguous about PROPERTY, it's hard to tell
> if it's an accessor at first sight. PROPERTY-VALUE is like SLOT-VALUE,
> but it's the longest to type.
>
> GETPROP is concise and Lispy. Thoughts?
>
> Vladimir
>
>> Best,
>> Red
>>
>>>
>>> Thanks,
>>> Vladimir
>>>
>>> 2009/11/25 Wout Perquin <wout.perquin at skynet.be>:
>>>> Hi Red,
>>>>
>>>> It works on my version too (*)
>>>> It is a clean solution that I like a lot.
>>>> I did some tests and the slot-value operator is quite versatile.  In
>>>> fact it makes aref redundant because (slot-value foo 1 2 3) renders the
>>>> same as (aref foo 1 2 3).
>>>>
>>>> It also allows constructs like :
>>>> (slot-value foo 1 "two" three 'bar 1 2)
>>>> => "foo[1]['two'][three].bar[1][2];" //not necessary meaningful but
>>>> possible :)
>>>>
>>>> I believe the versatility of slot-value should make it to the reference.
>>>>
>>>> Many thanks.
>>>> Best wishes, Wout Perquin
>>>>
>>>> (*) not sure what version I have, but the changelog youngest entry is
>>>> from Nov-4, 2007
>>>>
>>>> On Wed, 2009-11-25 at 00:10 -0800, Red Daly wrote:
>>>>> On Tue, Nov 24, 2009 at 12:43 PM, Wout Perquin <wout.perquin at skynet.be> wrote:
>>>>> > On Tue, 2009-11-24 at 19:42 +0000, Wout Perquin wrote:
>>>>> >> Hi,
>>>>> >> I would like to generate :
>>>>> >>       "var value = element[i].childNode[0].nodeValue"
>>>>> >> in one sentence.
>>>>>
>>>>> On my local version, slot-value accepts multiple slots:
>>>>>
>>>>> (slot-value element i 'child-node 0 'node-value)
>>>>> =>"element[i].childNode[0].nodeValue;"
>>>>>
>>>>> Nested @s and the like tend to become confusing, so I prefer this
>>>>> solution.  I don't know if it is part of the current Parenscript or
>>>>> not.
>>>>>
>>>>> Best regards,
>>>>> Red Daly
>>>>
>>>>
>>>>
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>>>>
>>>
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>>
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