model: Core: DateTime: Inherit from xsd:dateTime

[JPEWdev]

Inherit from xsd:dateTime instead of xsd:string. The XSD definition is compatible with the SPDX definition, and this will allow code generation tools to map the value to a code-native datatype.

[zvr]

👎 I disagree.

All our "Datatypes" are xsd:string with a pattern defining the valid format.

Note that Core/DateTime does not allow everything that xsd:dateTime does.

[JPEWdev]

The SPDX DateTime pattern is a strict subset of the allowed xsd:dateTime string, so it's not incompatible, it would just be a further restriction.

The nice part about using xsd:dateTime is that it means language bindings can know to use a native datetime type which is convenient for users; otherwise it just looks like another string.

[zvr]

Very briefly:

• I don't even know how dateTime values are represented in JSON-LD (asthey are not strings). I know that in other serializations, e.g. TTL, you have to always use something like "2024-03-14T12:34:56"^^xsd:dateTime and this is not very convenient.
• I am also not sure whether we can have SHACL pattern restrictions on non-string values. The SHACL online playground does not seem to support it, but I don't know whether this is a restriction of the implementation or the SHACL spec. On the other hand, if there are no validators that support it, the point is moot...

[goneall]

I did a bit of research on xsd:dateTime:

• It is a subtype of xsd:anySimpleType which is the base type for both dateTime and string - so it would be incompatible to switch this - probably a decision we need to make in 3.0
• You are allowed to further restrict xsd:dateTime with a pattern
• Based on several stackoverflow articles, I concluded that it is not common to restrict xsd:dateTime with a pattern, so we may get somewhat mixed results from some XML and RDF parsers

Based on the above I'm leaning towards changing the type inheritance to xsd:dateTime as proposed.

References:

• http://www.datypic.com/sc/xsd/t-xsd_anySimpleType.html
• https://www.w3.org/TR/xmlschema11-2/#dateTime

[kestewart]

Mostly agreed to in 3/19 meeting, if @zvr doesn't comment further by 3/28 - will be merged.

[kestewart]

Alexios joined, and agreed that decision made last week can stand. Merging.