ruby
Support IELR(1) Parser Generation
Support the generation of the IELR(1) parser described in this paper. https://www.sciencedirect.com/science/article/pii/S0167642309001191
This PR will be ready for merging when the following is done.
- [x] Add tests
- Currently, I have only created a grammar file and verified its operation in my local environment.
- [x] Refactor
- The data structure is awful and needs to be improved because the priority was to achieve the expected results.
A couple months ago I poked around the internet looking for independent IELR(1) implementations, and besides lrama found only an inactive rust-based attempt. Recently I completed my own implementation and wrote a technical report with the hope that it might help others. IELR(1) turns out to be a real bear to figure out, even if it takes only a moderate amount of code. I hope you find the time and inspiration to complete this effort. Good luck!
On https://github.com/ruby/lrama/pull/398/commits/7da96768fb91d6e017102a0b9a06528d7cf43f39 , Lrama can parse CRuby's parse.y at https://github.com/ruby/ruby/commit/028958f9ad83adbd1f7cb8e79167c9fb5e694535 .
These are the files of parsing results.
ruby path/to/id2token path/to/parse.y | bundle exec lrama -v - lalr
lalr.output
ruby path/to/id2token path/to/parse.y | bundle exec lrama -D lr.type=ielr -v - ielr
ielr.output
@junk0612 I created 2 test cases as reproduction of https://github.com/ruby/lrama/pull/398#issuecomment-2475464104. See https://github.com/yui-knk/lrama/commit/ca288c87b79592826bc0aa7861aff963b002deb5
