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

[Baptiste L. <bap...@gm...>]

2011/5/25 Aaron Jacobs <ja...@go...>

> Alright, I've implemented my understanding of the desired behavior in SVN
> revision 216, documenting the change in NEWS.txt.
>
> A few questions:
>
>  *  Could you take a look at NEWS.txt and tell me whether you agree with
> the
>    behavior? I made changes to the other isFoo methods to make them more
>    consistent and less surprising (for example, I don't know why null
>    returned true for isArray).
>

Concerning numeric it looks good. I'll make a more in depth review this
evening.

The behavior of isArray can be explained by the fact that a default
constructed Value can be though of as either an empty array or an empty
object: a nullValue is automatically "upgraded" to arrayValue or objectValue
on first array access or member reference. There is no distinction in the
(current) implementation between a default constructed value and a
nullValue.

This is that feature that allows the following usage:

Json::Value array;
array.append( 1234 );

Json::Value object;
object["age"] = 1234;

Maybe we should introduce a distinction between "default" initialization and
"null", but I'm not sure how to go about that...


>  *  It feels like now that these completely describe the safety of the
> asFoo
>    methods, the isConvertibleTo method is redundant. It's also not
> completely
>    descriptive, since it doesn't distinguish 64-bit integers. Should I
> delete
>    it? We don't ever use it at Google, but I suppose this may be a problem
>    for other codebases.
>

It is best not to break the code unless we have to. We can mark it as
deprecated and have the implementation forward to is* methods (64 variants
for int).

Notes that I have test failures on MSVS2010:
1>  * Detail of ValueTest/integers test failure:
1>  c:\perso\prg\vc\lib\jsoncpp-trunk\src\test_lib_json\main.cpp(626):
double(kint64max) == val.asDouble()
1>  c:\perso\prg\vc\lib\jsoncpp-trunk\src\test_lib_json\main.cpp(627):
float(kint64max) == val.asFloat()
1>  16/17 tests passed (1 failure(s))

Do you know what could be the cause? Otherwise I'll investigate...

There is also the problem of stdint.h which is not available before
MSVS2010:
src\test_lib_json\main.cpp(6) : fatal error C1083: Cannot open include file:
'stdint.h': No such file or directory
=> I'll check exact usage and see how to solve this issue for portability.

Baptiste.


>
> Aaron
>