[Cialug] What's a JSON Document?

[jim kraai]

Crockford's original grammar that was on the front page of json. org a few
minutes ago in the top-right corner of the page as rendered in my desktop
chrome browser starts with json:\n\telement

not elements, which is defined explicitly further down

so one element per file

but implementations deviate

um, for the love of all that's technically holy, please only put one thing
per json file

this is enforced implicitly by decoders that return a single decoded thing,
so even if one were to put in many top-level things, some implementations
return an array of decoded sub-things

also some implications allow # and /**/comments which gives me mixed
feelings, but the comments are invariably dropped, which leads me to...

here's a metric for evaluating behavior:  ignoring whitespace, does the
thing you started with equal decode(encode(thing))

also ignoring whitespace, does encode(thing) in one language/environment
equal encode(thing) in another

in different languages with different types you may get different results
because type hierarchies are rarely identical

stopping there


On Thu, Aug 30, 2018, 17:03 David W. Body <davidbody at bigcreek.com> wrote:

> A practical way to find out what is and isn't valid JSON is to use
> JavaScript's JSON.parse() and JSON.stringify() functions. You can do this
> in a node repl or in your browser's console.
>
> For example,
>
> > var p = JSON.parse("{}")
> undefined
> > p
> {}
> > var p = JSON.parse("{} {}")
> SyntaxError: Unexpected token { in JSON at position 3
> > JSON.stringify("hello world")
> '"hello world"'
> > var p = JSON.parse('"hello world"')
> undefined
> > p
> 'hello world'
>
> --David
>
>
> On Thu, Aug 30, 2018 at 1:25 PM, Dave Hala <dave at 58ghz.net> wrote:
>
> > I wonder if being loosely defined is actually problematic in practice?
> Has
> > anyone ever ran into a situation where exchanging data via json didn't
> > work?
> >
> > :) Dave
> >
> > On Thu, Aug 30, 2018 at 1:08 PM Scott Yates <Scott at yatesframe.com>
> wrote:
> >
> > > Since JSON often gets de-serialized, i tend to think of it as
> conforming
> > to
> > > a JavaScript "object".  Meaning "one object with many properties, or
> > nested
> > > objects/arrays"
> > >
> > > The problem (or advantage maybe) is that JSON is extremely loosely
> > defined
> > > (as you have noticed).
> > >
> > > On Thu, Aug 30, 2018 at 11:06 AM Todd Walton <tdwalton at gmail.com>
> wrote:
> > >
> > > > I know what JSON is. But I don't know what a JSON document is defined
> > as.
> > > > Wait, scratch that. It's not called a "document", it's called a
> "text".
> > > >
> > > > So I went off researching JSON this morning, and here are some
> things I
> > > > found:
> > > >
> > > > 1) ECMA defines it, of course, being it's derived from
> > > > JavaScript/ECMAScript. There's also an RFC: 8259.
> > > > 1a) RFC 8259 was published just last December!
> > > > 2)
> > > >
> > > https://www.ecma-international.org/publications/files/ECMA-
> > ST/ECMA-404.pdf
> > > > 3) https://tools.ietf.org/html/rfc8259
> > > > 4) ECMA says "JSON" is pronounced like "Jason". I prefer to say
> > > "jay-sawn".
> > > > 5) ECMA is a *lot* sloppier with their specifications than the IETF,
> > and
> > > > with the quality of their documentation.
> > > > 5a) <rant> ECMA! Shill for Microsoft. Skin disease. So on. </rant>
> > > > 6) "Hello, world" is a complete JSON text. Nothing says you have to
> > have
> > > > braces or brackets.
> > > > 7) Unicode is not actually strictly required.... (I did not expect
> > that.)
> > > >
> > > > So my question... Must a JSON text be *one* object or *one* array or
> > > *one*
> > > > unstructured string, number, or allowed constant? And must objects
> and
> > > > arrays be separated by a comma? Is the text between these dashed
> lines
> > a
> > > > conforming JSON text?:
> > > >
> > > > ------------
> > > > { "name": "Todd", "occupation": "scalawag" }
> > > > { "fruit": "orange", "delicious": true }
> > > > ------------
> > > >
> > > > --
> > > > Todd
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