Minutes for JSON at interim-2013-json-1
minutes-interim-2013-json-1-2

Meeting Minutes JavaScript Object Notation (json) WG
Title Minutes for JSON at interim-2013-json-1
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Last updated 2013-08-28

Meeting Minutes
minutes-interim-2013-json-1

   JSON VIRITUAL INTERIM - 2013-08-21 @ 15:00-18:00 UTC via Webex
NOTE: Meeting adjourned at approximately 17:00 UTC

SUMMARY
==============================================================

GENERAL APPROACH
--------------------------------------------------------------
There was much discussion about whether to explicitly document the individual
layers -- including an abstract data model; or to document the known likely
interoperability issues, leaving the existing document mostly intact.  While
some participants see merit in the layers approach, the rough consensus appears
to be that the effort is not worthwhile.  Instead, there appears to be rough
consensus to document the known likely interoperability issues.  For each
issue, the document will note the most interoperable behavior, and describe a
couple of behaviors that can lead to interoperability problems.  The normative
language will remain unchanged.

JSON TEXT
--------------------------------------------------------------
The rough consensus appears to be to start with Tim Bray's proposal, as
documented at <
http://www.ietf.org/mail-archive/web/json/current/msg01383.html >.

DUPLICATE NAMES
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The rough consensus appears to be to start with the duplicate names summary ,
as documented at <
http://www.ietf.org/mail-archive/web/json/current/msg01345.html >.

For determining the equality of names, there appears to be rough consensus to
compare values as if the values are unescaped, so that "a" and "\u0061" are
equal for purposes of name comparison.  John Cowan to propose some text to the
list.

ECMA TC39 / IETF JSON WG
--------------------------------------------------------------
The Area Directors and Chairs were made aware that Ecma TC39 is working on a
JSON specification.  However, the Area Directors and Chairs still believe the
efforts of the JSON Working Group are still worthwhile.  TC39 members were
invited to join the Working Group, but very few have participated.

NUMERICAL PRECISION
--------------------------------------------------------------
There appears to be rough consensus to start with what is representable using a
64-bit IEEE-754 double precision value.  Joe Hildebrand, Tim Bray, and John
Cowan volunteered to draft proposed text.

PROFILES
--------------------------------------------------------------
John Cowan asked about including a profile of JSON, similar to Tim Bray's
I-JSON < http://tools.ietf.org/html/draft-bray-i-json-00 >.  The rough
consensus appears to be to leave that as a separate draft that the Working
Group can consider once the chartered work is complete and it re-charters.

BEST PRACTICES AND OTHER DOCUMENTS
--------------------------------------------------------------
It was suggested that participants start work on a best practices for JSON,
similar to BCP 70.  However, that work is not currently in charter.

RAW NOTES
==============================================================

ACTIVE PARTICIPANTS
--------------------------------------------------------------

Barry Leiba (BL)
Eliot Lear (EL)
Jim Schaad (JS)
Joe Hildebrand (JH)
John Cowan (JC)
Larry Massinter (LM)
Paul Hoffman (PH)
Pete Resnick (PR)
Tim Bray (TB)
Tony Hansen (TH)

DISCUSSION
--------------------------------------------------------------

JH -- I think the approach we can do is to call out why something can challenge
interop, and strengthen the SHOULD (NOT) by explaining why it's a SHOULD (NOT).
 I agree it would make it clearer to have a better mental model, but I don't
think it's as important as making sure we explain how to not screw up.

JS - Do you mean we say SHOULD, but list why it might be ok?

JH - No, I mean SHOULD as in REALLY SHOULD, and explain how not following the
SHOULD can break things.

PH - I mostly agree with Joe, but think we shouldn't say SHOULD unless ...  I
think it is critical to say where interoperability issues might be, and not
following it might cause these interop issues.  But I don't think we should try
to categorize all of the vendors that operate certain ways.

JH - Right, I didn't mean specific vendors, but that we say "here are the
things can we've seen, and here's what you need to do to interoperate".

PH - Any other comments?

JS - I think that's a totally reasonable approach, and how I've been trying to
push for this in the JOSE documents.

TB - I'm mostly with Joe here.  I think we have a lot of shared concensus on
what the interop problems are.  If the result of our work is merely a document
that talks about what the problems can be, and call it done.  I don't think we
can strengthen the language any further.

JH - If we were to create a document that said "You SHOULD do this. But if you
don't do it, here are the interop problems."  Will the IESG have a problem with
that?

PR - I don't think there will be any issues, and I'm the one that whines about
2119 language.  SHOULD means you need to do this, and you accept all the things
that can go wrong if you don't.

BL - Are you not planning to talk about the interop issues?

JH - No, we're planning to talk about the issues.

PR - The fact is that you SHOULD NOT do duplicate names, and you can have
problems if you do.

PH - I'm not sure we can do a document that says do this and it won't interop.

JH - No, I mean that we say, if you don't do this, here are the ways it might
not work.

TH - We might want to talk about walled gardens.  In the walled garden, you'd
be fine, but outside you'd have problems.

PH - Are you suggesting we put that into the document?

TH - I think the document should talk about where you can expect
interoperability and where things become less interoperable.

JC - I want to qualify some more.  I think it's right to talk about things in
terms of might break, and not will break.  That while there might not be
problems now, but there can be in the future.

JH - Taking the duplicate names as an example.

JC- It's possible to map them.

JH - What I'm saying is there are parsers that generate different results

JC - I'm pointing to surrogates in particular, since the problem is more severe.

TB - We're trying to fix that.

JC - I'm just trying to say that there might be systems that can't fix the
issues.

PH - Where John's desire might be getting more interesting is the newest
issues.  We're trying to solve the problems we know about, but there can be
problems in the future.  We're not going to try to solve the problem for all of
the future.

JC - I have a problem with just "known", not "known possible".

PH,JH - Fine

TB - I don't see anyone have a problem with a document that is only listing the
interop problems, and that's great progress.

JH - I think one more thing we do need to talk about in the document is how
strings are compared, like what a human would think are equal but the

LM - Like saying this pertains to the abstract model and not the serialization
layer.

JH - I agree it would be cleaner to explain it that way, but I think that is a
much bigger edit than we have energy for.  I think it can be good enough to say

JC - Well, that you should compare them unescaped, but if you don't you will
have interop problems.

JH - Right.

LM - In IRI, we have Abstract layer, serialization, normalization, etc.  I
think that will help explain things better.

PH - So we have Joe's proposal to talk about ad-hoc explications versus Larry's
layer system.

JC - I would prefer the layer system in principal, but evading it [missed]

JS - I think we also need to talk about what you need to do to the value half
in addition to the name half in comparisons.

PH - Why is it important in JOSE?

JS - We have cases where we are caring about what the value of an attribute is,
and comparing it to other data I have.

PH - Is the JOSE WG finding that is something generally needed, or just for
JOSE.

JS - Right now, I'm the one with the issue and have raised it in the WG.  But I
see it as the exact same issue

JH - It may some combination of language for object name comparison plus PRECIS
rules for comparison.  But I'm not convinced we have a general requirement here.

JC - I think we move past values and onto significance of the meaning of
values.  We have whitespace, unless it's inside the string.  You can have as
much spaces and it doesn't impact the meaning.  So that also applies to
escaping; that the meaning of the escaping is what you are comparing and not
the literal string.

PH - These comparisons are being done for some type of hashing, and for
cryptographic comparisons?  My personal preference is that we don't talk about
removing escaping in value parts, and have the groups talk about it in the
terms that make sense for them.

JS - I don't care about the hashing. I care about say checking that the
algorithm value is the value I'm looking for.

JH - That's an application-level thing.

JC - So why are we not defining the algorithm?

JH - I'm trying to be clever because I might have a special way to handle it
for my platform.

JC - An analogy would be LATIN SMALL LETTER A WITH ACUTE versus LATIN SMALL
LETTER A combined with ACCUTE ACCENT.

JH - That brings up the specter of normailzation

JC - It's only an analogy.  If I send you something that would be a capital A
for me, but I can't assume you will see it the same.

PH - I think there will be implementations that do weird things, and we should
document what can cause interop problems.

JC - My point might be too subtle

PH - This topic might be for the best practices, which there is desire for but
yet in charter.

JC - If I send you a "\u0061", it means the same as "a"

PH - In a key, or any string.

JC - Any string.

PH - I believe that is true.

JH - I believe that is true, but I'm not convinced about the usefulness.  If we
were to have that discussion earlier in the document, then we can point to it
in the [missed]

JC - I note that it says "any character may be escaped", but it is a lower-case
may.

JH - What if we put something right after that they are compared to be the same.

JC - I think we need to be careful about equivalency and equality.

JH - I think that needs wordsmithing.

PH - So John is going to propose text about string comparison.

PH - To summarize -- we have some consensus that we document where there are
interop problems, how you can avoid them, and here are some of the ways that
they can break.

TB - I would fine-tune that some to be here are a non-exhaustive list of ways
you can break.

PH - That sounds good.

LM - I was hoping that someone from TC39 to talk about their JSON effort.

PH - You have asked, and we have invited them (including phone calls), but
they're not here.

TB - Are they working on a JSON standard?

PR - We have had conversations with TC39 in the last several days.  There is a
ECMA document on JSON floating around.  When I spoke to the Chairs (JSON and
TC39), and the basic idea is we continue doing the work that we think needs to
get done anyway, and we will deal with the Ecma output when/if it comes.  TC39
has not come out and said we should stop work, so we're not going to stop.

PH - Also, this work is not public.

LM - I am aware of that, and I don't think I'm revealing anything confidential.

PH - TC39 has known about this meeting, and they've chosen not to join us
today.  The Chairs have done the best that they can do, and the ADs plus Eliot
have done the best they can do.  The WG Chairs are not part of those AD + Eliot
discussions.

Coming back to this group: there have been proposals on the mailing list that
mostly match what we've talked about in this call.  Do people think we're ready
to move forward?

1) What is a JSON text
2) What does one do with dupicate names

There is no proposed text on number precision, but it is one area where interop
problems can come up.

JH - Do you mean floating point specific, or numbers in general?

PH - In general.  Tim had some proposals about the JSON text idea, and Matt
posted

JC - I think this is superseded by the "you might have interoperability
problems if...".

PH - Tim's proposal is talking about it in those terms.  My question is are we
moving too quickly?

JH - I think we should try and get a draft together.

JC - I agree

TB - I have seem a number of concrete proposals into the draft and see where it
goes

JH - I have one question about the text: I expect that all surrogates to be
paired, and all are encoded, etc...

JC - What do you mean by that?  Unmatched unencoded surrogate pairs don't exist
(-:

JH - My actual question: should we change the ABNF that you're not allowed to
do unpaired escaped.

JC - No, we cannot.  We must not.

PH - Why can't we.

TB - Because that would cause things that are JSON now to not be JSON anymore

JH - I was suggesting it go into the actual ABNF.  It was awful, but it was
legal.  I understand what you're saying about invalidating existing stuff.  But
I think we're invalidating it anyway when we change the text.

TB - No, we're going to say that "if you do these things, then you might have
interop problems".

LM - The abstract model allows for numbers that are valid numbers, but are not
valid Unicode.  There are interop because of bad implementations, and interop
problems because strings are used that don't map into the prescribed model.

JC - I know people use JSON to interchange JavaScript or Java strings, and
saying they can't exchange unpaired surrogates now means they don't comply.

JH - I'm willing to back off on that.  You're selling past the close.

PH - So take this to the list, and give it a week, then add the text to the
draft in a week?

JC - I don't object in principle, but I'm concerned in practice.  I don't think
we've talked enough about number precision.

PH - We understand, and it can still be hashed out.

NUMBERS
--------------------------------------------------------------

TB - If you do these things, then you can interoperate; if you don't then you
might have problems.  So for numbers, that I think that means you need to only
use numbers that represented in 64-bit IEEE 754.

PH - So what you're suggesting is we do numbers as a third point of interop,
and you SHOULD do it this way, and if you don't do it that way you can have
interop problems.

JC - Just make sure we're talking about the right format.

JC - I think there will be people that find this too broad, not too narrow.

JH - You think there are people that accept 32-bit floating point?

JC - I think so.  I think there are people that only accept integers.

JH - I think we can say it needs to be

TB - I work on a number of platforms, and 64-bit float isn't much of a problem.

JC - I think it needs to be at least discussed on list

PR - I'm a little concerned about paralleling the interop text here as in other
places.  It is about if you do this, then you have a good shot of interop; but
if you do this, then you can go wrong.

JC - For instance, I think one person said they can only handle fixed-point
numbers.

PR - It seems like it's different.  While it's a problem, it's not one the IEEE
format will completely fix.  I'm not sure this is the kind of text we should
put in.

PH - Two things: 1) precisions beyond 32-bit (or 64-bit) float, and 2) integers
only.  If someone only has a 32-bit float, and some of the things that can be
described in a JSON number and what will happen when the receivers gets those,
which is different from only handling integers.  If we hear that there are
implementations that only handle integers, then we need to discuss it in the
document.  If there aren't, but can only handle 32-bit float, then I don't
think we need to discuss it.  What we are talking about if we stop or not.

TB - The thing with surrogates is that the current spec implies you have to
deal with it, but it doesn't say you only deal with integers.

JC - It does allow for 0 digits after it.

TB - I think it's an agregious violation, but you might be right.

TH - Floating point is by its very nature non-interoperable when you go
between machines or into an on-the-wire representation that doesn't hold
the exact bit patterns. The best you can say is that sticking to a
format compatible with the IEEE standard would provide for the "best
chance of interoperability"

JH - And once you move it to base-10, then it gets worse

JC - 6427 § 4 says that an implementation on the range of numbers, but does not
say anything about the precision of numbers.

PH - So we can take this to the list.

JC - Omitting one and not the other implies a certain interpretation.

LM - Are you saying that having more 0's at the end is different than limiting
them?

EL - There is a law of physics in play here.  We haven't specified a limit, but
there will be.

JH - We can say that applications MAY put a limit of range and precision, and
most use IEEE 754 64-bit.

PR - That sounds like the right approach.

PH - (throwing in a wrench) As soon as we mention IEEE format, we are going to
have to say, BUT you can't do +/-Infinity and NaN.

JC - I'm fine with that.  We're saying that a number needs to be represented in
this format, but not that every IEEE is represented.

PH - OK, making sure we understand that.

PH - I hear a couple of volunteers for numbers.

JC - I think the three of us can come to consensus.

PH - I don't want the list to think we have a lot of contention, when we don't
really have any.  Can Joe/Tim/John come to internal consensus before going to
the list.

JC/JH - Yes.

OPEN MIC - ECMA RELATIONSHIP
--------------------------------------------------------------

PH - You've brought up the Ecma thing ... is there any specific concerns you
want to bring up now?

LM - I have heard that some at TC39 are not happy about no formal liaison.

EL - I sit on the IAB, and I have been talking to the TC39 people about this. 
There is an impedence mismatch between the IETF and ECMA.  The IAB doesn't see
the need for a long-term relationship so we don't want to formalize it.  The
IETF is open to everyone, and we think the best way to get people to talk is to
just have people talk.

LM - The mailing list is full about things that are foreign.  It's very
difficult to just come into the meeting room and start participate at any
point.  I think we should call them, and tell them we're having a meeting and
you should come here.

JC - We've done that, but they can't because they're under non-disclosure.

EL - I haven't heard that here.  We received a document, and we're reviewing
it.  There is a point on the charter about participation from Ecma, but they
haven't.

OPEN MIC - APPLICATION/FORM-DATA
--------------------------------------------------------------

LM -  I've been working on application/form-data, and it has a lot of the same
problems with non-ASCII values.  And separating things into layers helps better
define what needs to happen where.  We could say that the Abstract model only
contains integer values that can be interpreted as more; application models
might have IEEE and so on.  If you want to understand why the design choices
are what they are, then I think the layering helps do that.

JC - It would if it was in the data model.  I think that if we had the luxury
to start from scratch, it would be useable.  But we can't, so I don't think
it's useful now.

LM - I don't understand that, since the abstract model is already in the
applications today.

JC - I'm not understanding.

LM - The spec today says there are string and numbers, and there are problems
with precision and encoding, but it's not a problem in the abstract model.

JC - We went down this road in XML.  We couldn't agree on what is in or out of
the data model.

LM - Does JSON have the same problems as XML?

JC - No, because no one as attempted to write a JSON data model.

PH - For the WG, does a data model document go into 4627, or in something else?

LM - I'm not proposing the data model as anything more than a way to describe
why certain choices were made.

PH - I suggest that we hold that discussion for the mailing list.  There are a
variety of understanding of implementers, and not identical.  Having a data
model would be valuable in an implementer's guide, but not in 4627bis.

JC - Or a user's guide

PH - When it's about what's next.  Do we need an implementer's guide, or a
combination implementer's/user's guide.  We propose that you write up the data
model, but not for inclusion in 4627bis.

OPEN MIC - PROFILE
--------------------------------------------------------------

JC - The idea of a Tim Bray profile of JSON, in the 4627bis.  If you want to
maximize interop, obey all of these rules...rather than scattering them
throughout the document.

PH - Do they belong in the document at all, and then do they belong in a single
section?

TB - No, that would read weird.  Put things where you talk about it.

PH - So you want scattered?

TB - I want do judiciously sprinkle the interop guidance and challenges.

PR - There are instances where there are clear interop problems, and that's
different than maximizing interop.  I think we have consensus on the specific
problems, and it sounds like you want a more general guidance.

JC - I bring it up because §4 talks about parsers dropping data.

TB - I think what John is trying to assemble is my I-JSON draft into 4627bis?

JC - I'm not necessarily saying we have it in multiple places, but that we
should have all of these points gathered into one place, so we can reference it
as a profile.

TB - I think we know what the biggest problems, and we can do localized
surgery.  This is also about having an interoperable profile in this document,
but it requires a lot more.

JC - I agree at that level it's not in our scope. But now I wonder if there are
interop problems if using something other than UTF-8?

PH - 4627 does have an IANA consideration, which is a MIME registration that is
inviolate.  It only talks about UTF-8 ,-16, and -32.

JH - I agree with what Paul and Tim said, and we can't change what people are
using today, but that we should have another document that

JC - I'm asking if we say that if we don't limit to UTF-8, that anyone that
does limit is not interopable.

JH - I'm aware of one that only understand UTF-16 ... like ECMA-262.  I don't
think this is a good path to go down.

OPEN MIC - BCP 70
--------------------------------------------------------------

LM - I did ask about BCP 70.  It seems like we should have something like BCP
70 for JSON.

PH - There is interest, but we're not ready for that yet.

LM - I'd like to solicit volunteers on that, and other parking lot things.

PH - I think you should keep that list, but I don't want to interrupt the WG
process.  It's not on the charter now.

OPEN MIC - NEXT STEPS
--------------------------------------------------------------

JH - I've sent along small edits to Tim and John, so we should have something
out soon.