Who uses them? I know someone who wrote a GLR parser generator, but I've never seen the algorithm used in production.
I've heard of one C++ front end that uses it -- Elkhound -- but the only context I've heard of Elkhound is in GLR parsing! As far as I can tell Clang is now the state of the art. (i.e. Clang probably does everything Elkhound does, but better and faster.)
I have looked at least 30+ parsers for programming languages. I see:
- hand-written recursive descent (with operator precedence for expressions)
- yacc (Ruby, R, awk, etc.)
- ANTLR
- Bespoke parser generators
- Python's pgen.c - LL(1) with some tricks
- sqlite's Lemon - similar to Yacc except you push tokens
That's about it. I've never encountered notable usages of Earley or GLL or GLR parsing.
I've heard of one C++ front end that uses it -- Elkhound -- but the only context I've heard of Elkhound is in GLR parsing! As far as I can tell Clang is now the state of the art. (i.e. Clang probably does everything Elkhound does, but better and faster.)
I have looked at least 30+ parsers for programming languages. I see:
That's about it. I've never encountered notable usages of Earley or GLL or GLR parsing.