SPARQL Grammar: initial text direction; nested reified triples

[afs]

This PR updates the SPARQL Grammar to include initial text direction syntax and functions. There is also a fix for nested reified triples.

This replaces the grammar changes in #113 in order to get all the SPARQL 1.2 grammar changes into the working draft.

The rest of #113 (updated) with the the function definitions will follow separately.

Initial text direction functions:

• Functions isLang, isLangDir, LANGDIR, and STRLANGDIR.

Changes to reification:

• Fix: allow reified triples to be nested.
• Fix: remove production ReifiedTripleData (removal causes renumbering)

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Preview | Diff

[pchampin]

This was discussed during the rdf-star meeting on 12 September 2024.

View the transcript

w3c/sparql-query#153

AndyS: line item 7, I did an update for grammar of query for 1.2 features.
… triple terms, annotation syntax, language directions.
… just the grammar, not the text or functions.
… believe it's reasonably complete.
… we should wait. difficult to review just grammar changes.
… hoping we could give it a week or so. then merge. then take corrections on that.

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[afs]

Updated with a fix for nested reified triples and including the effect of w3c/rdf-turtle#71 depending on how that issue being resolved (it only has a local effect on the grammar).

After this PR merges work to do includes:

• a tidy-up pass over the grammar to find common definitions
• align naming with Turtle where appropriate
• reorder new rules
• Use data-include= to move the grammar to a separate file. Downside: it does not display in PRs or locally (the same is true for Turtle which does use data-include=.

[gkellogg]

It would be nice to have a text version of the grammar in the repo, similar to how Turtle does.

[afs]

Should be possible. javacc produces a text form - the terminals need munging in a similar fashion to the HTML generating script (perl).

Later though - not this PR.

BTW The Turtle spec does not seem to have link to the text turtle.bnf file.

[gkellogg]

No, it doesn’t right now. I’ll do a PR to add that link.