Re: [Json] Allow any JSON value at the top level

[Tatu Saloranta <[e-mail]>]

On Mon, Jun 10, 2013 at 3:53 PM, Jorge <[e-mail]> wrote:

> It seems to me that top-level JSON values are a problem *only* for
> *streaming* parsers.
>
> A streaming parser can't tell whether the stream 333 was 3 separate threes
> or three-hundred-thirty-three, or even part of an incomplete 333445, or
> (chop it as you like).
>
> Parsing a stream with the other data types (strings, null, booleans): e.g.
> say, this stream: "string"truenullfalse"anotherstring"null"string"true"etc.
> etc." doesn't seem to be so much a problem (unless it gets out of sync!).
>
> But non-streaming parsers (such as the ones in EcmaScript 5) haven't any
> of these problems because they expect to receive a complete JSON payload
> containing a single JSON value (structured or not) and that's easy to parse
> unambiguously.
>

FWIW, streaming parsers I have been involved with expect separating
white-space and have no problem telling these cases apart; although it does
require a lookup to detect a white-space or end-of-stream.
Although there is no support from specification (since non-structured root
values are not specified as acceptable), this seems intuitive from user
perspective based on feedback I have gotten on this. This despite there
being theoretical problems (like: should commas be allowed or required, for
"implicit array" approach).

But what John C pointed out -- truncation of '333' from full '333445' -- is
actually an interesting and valid potential issue.

-+ Tatu +-