SHACL Compact Syntax, was Re: Fwd: Transition Request: 3 FPWGNOTE documents

Tom's email, to which Irene is replying, was send to a W3C Member 
Confidential mailing list (chairs@w3.org).  She accidentally included it 
in her reply, perhaps not knowing the list's confidentiality (which is 
not obvious).   Here's my to reply to that list, which bears on this 
this group:

> My sincere apologies, Tom.  You mentioned this concern to me earlier, 
> and then I completely forgot about it in the flurry of documents.  
> That was a serious error on my part.
>
> I agree, it's a very bad architectural practice to design languages 
> such that a non-trivial document could be syntactically valid in 
> multiple languages while having different semantics.   We pretty much 
> only see this in a few notoriously bad situations, like "1/2/2017" 
> being either 2017-01-02 or 2017-02-01, depending on the locale.
>
> I suggest the Data Shapes Working Group withdraw its decision to 
> publish this (or the Director not approve it), and instead delegate to 
> an expected new SHACL CG to figure out a way to make the syntax 
> disjoint from ShExC in at least the cases where the semantics are 
> distinct, [then] publish it as a CG Report, much like ShExC, instead 
> of a WG Note (since the WG will presumably have expired by then).

Does that sound like a reasonably path forward?

I guess another option would be to make a trivial change to the syntax 
(before next week) to make it disjoint, but I believe the community 
would be far better served by having the syntax be the same in places 
where the semantics are the same.  If that's possible, it seems 
worthwhile to take the time in a CG to figure that out in concert with 
ShEx folks.

Thoughts?

       -- Sandro


On 05/24/2017 11:57 AM, Irene Polikoff wrote:
> I really do not think ShEx has a “copywrite" on an idea of a compact 
> syntax. Its syntax itself was itself influenced by many different 
> syntaxes/previous works, I am sure.
>
> Further, the syntaxes are not identical. They are similar. For 
> example, SHACL has target declarations and it is supported in the 
> syntax. The way cardinalities are expressed is different.
>
> I guess one option would be to modify the syntax to be even less 
> similar. But I can’t think what could be done to make it significantly 
> more different - because the information it is trying to express is 
> very similar and it is expressed in an obvious way as a “property”, 
> then a list of constraints for the values such as the data type, 
> cardinality, etc. There is nothing novel or special in this format.
>
> I suppose one could change delimiters. However, many delimiters are 
> quite standard and making them into something else would be very 
> peculiar e.g., the use of ‘|” for ‘or’; the use of “;”  as a 
> separator. These are used by many-many languages. With this, I am not 
> sure what changes would be sufficient to ensure that SHACL and ShEx 
> compact syntax can’t be confused. Should SHACL WG members object to 
> the ShEx CG use of the words ‘shape’, ‘node shape’, etc.? Because this 
> will be confusing to potential users - when they hear or see shape, 
> they wouldn’t know which one.
>
> Overall, this sounds like an attempt to prevent SHACL from having a 
> compact syntax so that for those who want a compact syntax, ShEx will 
> be an only option. This is not good for the community and, to me, 
> sounds like a desire to block progress and deprive users of SHACL of 
> features. No one should have a right to do this, especially not on the 
> open web.
>
>
>> Begin forwarded message:
>>
>> *From: *Tom Baker <tom@tombaker.org <mailto:tom@tombaker.org>>
>> *Subject: **Re: Transition Request: 3 FPWGNOTE documents*
>> *Date: *May 24, 2017 at 11:05:47 AM EDT
...