Re: [Json] Proposed rechartering for the JSON WG

[Nico Williams <[e-mail]>]

On Sat, Feb 8, 2014 at 5:52 PM, Tim Bray <[e-mail]> wrote:
> On Sat, Feb 8, 2014 at 2:50 PM, Nico Williams <[e-mail]> wrote:
>>
>>
>> An XPath/XSLT for JSON would be good.  There's a great candidate for
>> that: http://stedolan.github.io/jq .
>
>
> jq seems like overkill. Wow, would it ever be easy to do a JSON path
> selector.   They practically read themselves
>
> "buffer"/"size"

FYI:

.buffer.size

> //"size"

recurse(.[]).size

> //"buffers"/./"size"

recurse(.[]).buffers[].size

> //"buffers"/0/"size"

recurse(.[]).buffers[0].size

The .name syntax is a bit to type-strong and so you get spurious error
messages (safely ignored).  I think the right thing to do here is to
make .name act like 'empty' when . is not an object, or if name is an
integer, when . is not an array (but .[number] needs to continue to
produce warnings if . is not an array).  That and add ..name syntax,
then '..buffers.0.size' should do what you want without spurious error
messages.  I'll defer to Stephen either way.

BTW, I've needed // in XPath very often.  But I've never needed it
when dealing with JSON data.  The JSON data I've dealt with never had
more than one layer of structure repetition, while XML data I've dealt
with had many.

> //"buffers"/-1/.

This one's a pain as jq doesn't do negative indices, so you have -1 the length.

> "buffer"/./"key"

See above.

Nico
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