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Re: JSON-LD (Was:Re: Vaccination Certificate Test Suite)

From: Leonard Rosenthol <lrosenth@adobe.com>
Date: Mon, 26 Apr 2021 15:44:56 +0000
To: Manu Sporny <msporny@digitalbazaar.com>, "public-credentials@w3.org" <public-credentials@w3.org>
Message-ID: <MN2PR02MB6992EC036106AE0C3462E189CD429@MN2PR02MB6992.namprd02.prod.outlook.com>
It’s also worth noting that Schema.org has an unfortunate name, because it doesn’t actually have any machine readable schemas available ☹.   One of the advantages of using XML (or even JSON) schema is that they are actually schema definitions that can be used for machine validation and semantic understanding.

I’ve had to write my own JSON schemas for certain Schema.org grammars that were worthy of consideration for specific use cases.

Leonard

From: Manu Sporny <msporny@digitalbazaar.com>
Date: Monday, April 26, 2021 at 10:59 AM
To: public-credentials@w3.org <public-credentials@w3.org>
Subject: Re: JSON-LD (Was:Re: Vaccination Certificate Test Suite)
On 4/26/21 10:26 AM, Nikos Fotiou wrote:
>> those values should be:
>>
>> https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema%23date&amp;data=04%7C01%7Clrosenth%40adobe.com%7C3658dfa30b064ff2012f08d908c3df14%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C637550459621752231%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=Ip7Ria2DSoGqPrpiM16VI0zfHL0QnbB1osKoT3ndUOw%3D&amp;reserved=0
> So why this, and not e.g., https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fschema.org%2FDate&amp;data=04%7C01%7Clrosenth%40adobe.com%7C3658dfa30b064ff2012f08d908c3df14%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C637550459621752231%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=3cFb%2F7zvAjnxvTBdC1JcvAjwn4Dt3NtDi4g4B9jdXho%3D&amp;reserved=0?

The short answer is "history and precedence".

There are many more systems on the planet today that understand
`https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema%23date%2560&amp;data=04%7C01%7Clrosenth%40adobe.com%7C3658dfa30b064ff2012f08d908c3df14%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C637550459621752231%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=EumQhxR9hCblWWNblkqd4P9LG1WXJi1q2VT4uSkNuuc%3D&amp;reserved=0 than `https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fschema.org%2FDate%2560&amp;data=04%7C01%7Clrosenth%40adobe.com%7C3658dfa30b064ff2012f08d908c3df14%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C637550459621752231%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=ewNJKWQSxNgJ3T8G6AvEoYHHKzIOGmEBWeleO%2FWupew%3D&amp;reserved=0...
mostly because the former has existed for 20 years, and the latter has only
existed for 10 years (and is targeted at search engine optimization). The
former is used across healthcare, government, a TON of systems that are
powered by XML (retail, banking, etc.), while the latter is mostly for SEO and
is mainly used at Google, Bing, and Apple.

This is where things start transitioning towards "art" from "hard science".
There is no hard rule on this... Tobias could have used `Date`... the value
space is the same, but I expect he chose to use `XMLSchema#date` because of
the larger body of software systems that understand the property.

I think it's the right call... at the end of the day, we just need to use a
URL to identify the concept of a "date". One could even argue that
`schema.org/Date` and `XMLSchema#date` are semantically equivalent (they are,
and they have the same value space, IIRC). We could add reasoning statements
into our software to detect both as equivalent, but that would add complexity
to software... so, we try to not do that and just use the URL that people have
been using to represent ISO-8601 dates for 20+ years now.

-- manu

--
Manu Sporny - https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.linkedin.com%2Fin%2Fmanusporny%2F&amp;data=04%7C01%7Clrosenth%40adobe.com%7C3658dfa30b064ff2012f08d908c3df14%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C637550459621752231%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=ruFpvrpQHhCFZ0s5JU4XNKb3tnbn%2BxPIzJdKWP16pb4%3D&amp;reserved=0
Founder/CEO - Digital Bazaar, Inc.
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Received on Monday, 26 April 2021 15:45:11 UTC

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