Jifa is a reference implementation of IfA language, a declarative query language for {syntactic / semantic / pragmatic} web.
From root-dir: gradle build or gradle run
All grammar, parser, and semantics are developed inside src/test/grammar/. Just go there and read README.md file. Once finish, copy JifaGrammar.peg, JifaParser.java, and JifaSemantics.java into src/main/java/xyz/bpdp/vastix/jifa/.