Re: [Jsoncpp-devel] Backwards incompatible change in jsoncpp 64-bit support

[Stephan B. <sg...@go...>]

On Wed, May 25, 2011 at 10:52 PM, Aaron Jacobs <ja...@go...> wrote:

> Hmm, but does it make sense to say a default constructed value is all
> of null, an array, and an object? Wouldn't it make more sense to have
>

In JS, default-constructed values are 'undefined', not null:

[stephan@cheyenne:~/tmp]$ js
Rhino 1.7 release 2 2010 11 17
js> var x; print(typeof x);
undefined

(And (typeof null) == object, for some brain-dead reason or other.)

IMO that is the proper default-construction semantics. The further a JSON
impl deviates from basic JS behaviours, the less portable it is likely to
become.


isArray (and only isArray) start returning true once the value is
> "turned into" an array by appending something to it?
>

Using JS as a baseline:

js> x[1] = 3;
js: "<stdin>", line 3: uncaught JavaScript runtime exception: TypeError:
Cannot set property "1.0" of undefined to "3"
at <stdin>:3

that's the behaviour most would expect, i think (as opposed to automatic
promotion to an Array or Object).

-- 
----- stephan beal
http://wanderinghorse.net/home/stephan/