sparql-update-mode, tarql-mode; syntax checking with flycheck

[VladimirAlexiev]

@ljos thanks for your very excellent mode! I also use it for writing SPARQL UPDATEs and TARQL tabular conversions.

Could you make 2 more derived modes: sparql-update-mode (ext *.ru), tarql-mode (ext *.tarql)?

• http://rawgit2.com/VladimirAlexiev/grammar-diagrams/master/sparql11-grammar.xhtml shows the syntax of SPARQL and SPARQL UPDATE together.
• https://github.com/ljos/sparql-mode/issues/29#issuecomment-779816728 describes the syntax of TARQL, which is SPARQL plus a tiny bit more (allows several CONSTRUCT).
• sparql-mode already highlights UPDATE keywords (eg insert, delete)

So the only thing that I'm missing is syntax checking.

• 29 explores advanced topics like LSP but hasn't been implemented in 7 years.

• @bjonnh has showed a very simple implementation as a flycheck checker.
• The same checker can be used for sparql-update-mode, tarql-mode: the only thing that needs to be changed is the executable name, and add a few more regexes. On Windows the executables are *.bat (as shown below), on linux are *, on Cygwin are either:
  • sparql-mode: ("qparse.bat" "--query" source)
  • sparql-update-mode: ("update.bat" "--update" source)
  • tarql-mode: ("tarql.bat" source)

Output examples:

qparse --query foo.rq
Encountered " <DELETE_WHERE> "delete where "" at line 5, column 1.
qparse --query bar.rq
Lexical error at line 2, column 11.  Encountered: " " (32), after : "z"
qparse --query baz.rq
Line 2, column 17: Unresolved prefixed name: ...

update --update foo.ru
org.apache.jena.query.QueryParseException: Variable used when already in-scope: ?upd in ((AGG ?.0 MAX(?new)) AS ?upd)
update --update bar.ru
org.apache.jena.query.QueryParseException: Encountered " "." ". "" at line 6, column 67.

tarql foo.tarql
Error parsing SPARQL query: Encountered " <DELETE_WHERE> "delete where "" at line 5, column 1.
tarql bar.tarql
Error parsing SPARQL query: Lexical error at line 1, column 1.  Encountered: "\u0016" (22), after : ""
tarql baz.tarql
Error parsing SPARQL query: Line 2, column 17: Unresolved prefixed name: ...