I am so happy to find modular Happy packages.
Happy is a parser generator system for Haskell, similar to the tool Yacc for C, OCamlYacc for OCaml, and so on. It has been used for generating a GHC's Haskell parser.
Since its birth, it has been a monolithic architecture. Now it is time to make it modular so that Happy can be used more than just GHC's Haskell parser.
- piknotech/happy{modularization branch}
It consists of happy-{frontend,middleend,backend,core,test} packages. Happy-frontend is for reading .y files and parsing them into the Grammar datatype. Happy-middleend applies LR/GLR parsing algorithms to the grammar to have action tables and goto tables. Happy-backend generates template-based Haskell code using these tables. Happy-core defines common interfaces among these packages, and Happy-test is about a testing framework. It is said to have the same CLI as the original monolithic Happy so that the transition from the existing one to this one can be as smooth as possible. Isn't it great?
This is how to install this modular Happy packages in modular_happy directory.
$ mkdir modular_happy; cd modular_happy
$ git init
$ git remote add origin https://github.com/piknotech/happy
$ git pull origin modularization
(You don't have to build it for now.)
You can test these packages with GHC's Parser:
- Parser.y
Just to read this Parser.y and to print it in Grammar datatype, this simple program is enough.
$ stack new example; cd example (Assume example and modular_happy are in the same level)
(Include the following in package.yaml)
dependencies:
- base >= 4.7 && < 5
- happy-frontend >= 1.21.0
- happy-middleend >= 1.21.0
- happy-backend >= 1.21.0
- happy-core >= 1.21.0
No comments:
Post a Comment