[x3d-public] MFString quoting [was: interesting sample] JSON escaping example

[John Carlson]

What's really sad is I spent a lot of time getting the existing JSON
working on the server side, with conversion to XML, Java and JavaScript.
I suspect that will have to be redone.   I need to include the GUI next
time.

John

On Apr 27, 2017 6:22 AM, "Roy Walmsley" <roy.walmsley at ntlworld.com> wrote:

> Hi,
>
> The trick when considering translating from XML encoding to JSON encoding
> is to think of the what is needed in the middle, i.e. what is loaded into
> memory, or, equivalently, what would be displayed on the screen. So,
> considering the examples below one at a time:
>
>         X3D  "quote mark  \"  is &quot;"
>
> I presume that the term X3D implies that we looking at an XML  encoding of
> a string. So, what we want to see on the screen is
>
>         quote mark " is "
>
> The escaping rules for JSON are simple. An easy to understand diagram is
> at  http://www.json.org/. So translating this memory representation to
> the JSON encoding gives:
>
>         "quote mark \" is ""
>
> Notice that the ampersand shall not be escaped in the JSON encoding. In
> fact, only the quotation mark " and the reverse solidus \ have to be
> escaped. The escaping of the forward solidus / is optional.
>
> Now let's look at the second example.
>
>         JSON "empty string \\\\\"\\\\\" skips a line:",
>
> This is already a JSON encoding. So a parser will load this and display
> the following string
>
>         empty string \\"\\" skips a line:
>
> Clearly that is not what is desired. What you want to see is:
>
>         empty string "" skips a line:
>
> So, encoded into JSON this becomes
>
>         "empty string \"\" skips a line:"
>
> Similarly, encoded into the XML encoding gives
>
>         "empty string \"\" skips a line:"
>
> So yes, I would conclude that you are far too zealous in adding all those
> backslashes.
>
> Remember, you are not trying to write an XML encoded string as a JSON
> encoding. You are going via computer memory, where loading the XML encoding
> undoes all the escaping. You then only have to do the new escaping on the
> unescaped string.
>
> Hope this helps. Happy to talk if you want. Especially as I haven't
> involved stylesheets in the discussion above!
>
> All the best,
>
> Roy
>
> -----Original Message-----
> From: x3d-public [mailto:x3d-public-bounces at web3d.org] On Behalf Of Don
> Brutzman
> Sent: 27 April 2017 03:30
> To: John Carlson <yottzumm at gmail.com>
> Cc: x3d-public at web3d.org
> Subject: Re: [x3d-public] MFString quoting [was: interesting sample] JSON
> escaping example
>
> On 4/26/2017 4:02 PM, yottzumm at gmail.com wrote:
> > I do have a problem with the JSON encoding for the attached file
> (translated by X3dToJson.xslt).  Let me know if you think otherwise.  Look
> at all the \\\\\.
>
> i suspect the issue is illustrated by the following SFString within an
> MFString
>
>         X3D  "quote mark  \"  is &quot;"
>         JSON "empty string \\\\\"\\\\\" skips a line:",
>
> will try to break it down.
>
> double-backslash escaping going on here for JSON; so internal content-only
> correspondences should likely be
>
>         [X3D ]  \
>         [JSON]  \\
>
>         [X3D ]  "
>         [JSON]  \"
>
>         [X3D ]  \"
>         [JSON]  \\\"
>
>         [X3D ]  quote mark  \"  is &quot;
>         [JSON]  quote mark \\\" is "
>
> please count.  does that look right?
>
> if so, then it looks like the X3dToJson.xslt is overzealously prepending 2
> extra backslashes in this particular case (one of several).
>
> if not, then please advise what the right answer is.
>
> also please re-advise, where are the JSON backslash-related rules?
>
> if we can agree on what the right answer looks like, then i will dive back
> into the independently XML/XSLT/XPath escaped (and obtw recursive)
> stylesheet template that consumes/produces this stuff to try doing the job
> correctly.  (gulp!)
>
> p.s. if anyone out there isn't dizzy yet, congrats!
>
>
> > Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
> >
> > *From: *Andreas Plesch <mailto:andreasplesch at gmail.com>
> > *Sent: *Wednesday, April 26, 2017 5:21 PM
> > *To: *John Carlson <mailto:yottzumm at gmail.com>
> > *Cc: *Don Brutzman <mailto:brutzman at nps.edu>; X3D Graphics public
> mailing list <mailto:x3d-public at web3d.org>
> > *Subject: *Re: [x3d-public] MFString quoting [was: interesting sample]
> >
> > On Wed, Apr 26, 2017 at 3:55 PM, <yottzumm at gmail.com <mailto:
> yottzumm at gmail.com>> wrote:
> >
> >     It’s
> >
> >     http://x3dgraphics.com/slidesets/X3dForWebAuthors/
> Chapter02GeometryPrimitives.pdf
> >
> >     Got caught in the grand renaming.  Also the parent page is wrong.
> >
> > Thanks.
> all the best, Don
> --
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149
> X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/
> brutzman
>
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