Come up with a parser-based solution for SPARQL query modification

[lu-pl]

Since there is no proper/applicable SPARQL query builder solution available for Python, SPARQL query modification in RDFProxy currently has to rely on regexes. Obviously, this is a huge pain.

A much more stable, reliable and sane approach of doing dynamic query modification would be to modify a parse tree instead of strings. So it would be really nice if somebody (me) came up with a parser capable of dynamic parse tree modification. RDFLib's SPARQL parser is built with pyparsing, so this is likely not an option.

[lu-pl]

I am of the opinion that a lark parser would be a good solution, lark has neat Transformer and Visitor abstractions for operations on the parse tree and is generally really powerful. Also, lark's grammar syntax is very close to EBNF.

[lu-pl]

larql is an attempt to create a Lark parser for SPARQL 1.1. It tests against w3c rdf-tests, currently 1/3 of the tests are failing, almost all of them concern Update Requests. Working on it.

[lu-pl]

update: the remaining failing tests are often about SPARQL semantics, not its syntax. So larql will probably have to provide a thin-ish wrapper for semantic pre- and post processing of parsed queries.