Switch to a different parsing library

[liss-h]

Due to the lacking performance of ANTLR consider switching to a different parsing library.

Question: Is SPARQL context-free? (i.e. parsable with parser-combinators)
Answer: yes

Possible Libraries to look into (in no particular order):

• https://github.com/taocpp/PEGTL (parser combinator)
• https://github.com/foonathan/lexy (parser combinator)
• https://tree-sitter.github.io/tree-sitter/ ("general enough to parse any programming language")
• https://live.boost.org/doc/libs/1_68_0/libs/spirit/doc/x3/html/index.html (LL parser using EBNF)

Important features:

• fast
• correct
• easy to maintain
• expressive parsing errors
• stream support (optional?)

[liss-h]

Also: ANTLR causes stack overflows on deeply nested path queries -> resolved