https://github.com/rizo/ppx_rule

Compile-time rewrite rules for OCaml
https://github.com/rizo/ppx_rule

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Compile-time rewrite rules for OCaml

• Host: GitHub
• URL: https://github.com/rizo/ppx_rule
• Owner: rizo
• License: bsd-2-clause
• Created: 2016-01-15T04:03:09.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2016-01-15T14:29:33.000Z (almost 9 years ago)
• Last Synced: 2023-03-11T03:57:02.023Z (almost 2 years ago)
• Language: OCaml
• Homepage:
• Size: 15.6 KB
• Stars: 18
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        

# Compile-time optimization rules

This syntax extension implements compile-time rewrite rules to offer a powerful and flexible way to optimise your programs.

Consider the following simple examples:

```ocaml

(* Helper functions *)

let sum x y = x + y

let hello who = "Hello, " ^ who

(* Rules *)

let%rule sum 2 2 = 5

let%rule hello "rule" = "rules rock!"

let%rule sqrt 100000000000.0 = 316227.766017

let replaced = (sum 2 2, hello "rule", sqrt 100000000000.0)

let computed = (sum 1 1, hello "world", sqrt 99.0)

```

The syntax processor will replace the known patterns during the compilation time.  

After the application the resulting code will look like this:

```ocaml

let sum x y = x + y

let hello who = "Hello, " ^ who

let replaced = (5, "rules rock!", 316227.766017)

let computed = (sum 1 1, hello "world", sqrt 99.0)

```

Note that the rules disappear during the compliation, so no runtime overhead is added to the program.

For more examples see the `tests` directory and for build options run `make help`.

## Known Limitations

- Parametric rules are not implemented yet.

- The visibility of the rules is limited to the module where they were declared.

- Recursive rules may have unexpected results.

## Project Status

This project is still in development and at this point should be considered a proof of concept, please use with care.

This syntax extension was inspired by [Rule pragma](https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/rewrite-rules.html) for Haskell.