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https://github.com/smolkaj/nice-parser
Nice parsers in OCaml without the boilerplate
https://github.com/smolkaj/nice-parser
boilerplate dune lexing menhir ocaml ocamllex parser-generator parsing
Last synced: about 2 months ago
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Nice parsers in OCaml without the boilerplate
- Host: GitHub
- URL: https://github.com/smolkaj/nice-parser
- Owner: smolkaj
- License: mit
- Created: 2017-04-25T22:50:37.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2024-05-06T17:26:24.000Z (8 months ago)
- Last Synced: 2024-05-19T06:00:04.811Z (7 months ago)
- Topics: boilerplate, dune, lexing, menhir, ocaml, ocamllex, parser-generator, parsing
- Language: OCaml
- Homepage: https://smolkaj.github.io/nice-parser/nice_parser/
- Size: 486 KB
- Stars: 121
- Watchers: 8
- Forks: 14
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGES.md
- License: LICENSE
Awesome Lists containing this project
README
*For an older version of this repository based on sedlex, refer to the [sedlex branch](../../tree/sedlex)*.
# Nice Parser
[](https://github.com/smolkaj/nice-parser/actions)
Writing an OCaml parser with nice error messages should be easy - and now it is!
*Nice Parser* comes in two parts:
1. **lib/**: The [`nice_parser`](lib/) library ([API](http://smolkaj.github.io/nice-parser/nice_parser/)) consolidates boilerplate code and wraps your auto-generated parser in a *nice* interface with beautiful error messages.
In types: `Nice_parser.Make : functor(P : RAW_PARSER) -> NICE_PARSER`.
2. **example/**: The example parser lets you get started on your own parser in seconds. It is based on [`nice_parser`](lib/) and standard tools:
* [Menhir](http://gallium.inria.fr/~fpottier/menhir/), a LR(1) parser generator.
* [ocamllex](https://caml.inria.fr/pub/docs/manual-ocaml/lexyacc.html), OCaml's built-in lexer generator.
* Jane Street's [dune](https://dune.build/) and [base](https://opensource.janestreet.com/base/), the de-facto standard built tool and standard library for OCaml.
Using the library and the skeleton, you can get started on your own parser in seconds:
```sh
git clone https://github.com/smolkaj/nice-parser.git # clone this repository
cd nice-parser && rm -r lib && mv example src # use example as starting point
opam install . --deps-only --with-test # install dependencies
dune build # try to build...
dune exec src/bin/main.exe # ...and run your parser!
```
You should see the following output (the error message relies on OCaml >= 4.08's new [source highlighting mechanism](https://github.com/ocaml/ocaml/pull/2096)):
```
Trying to parse "(a b (c d) e)".
-> (List ((Atom a) (Atom b) (List ((Atom c) (Atom d))) (Atom e)))
Trying to parse "(long_atom_with_0123)".
-> (List ((Atom long_atom_with_0123)))
Trying to parse "
( so far so good
but (this is)) illegal (isnt it?)
(* parsing will fail ^^^^^^^ here *)
".
Fatal error: exception Line 3, characters 25-32:
3 | but (this is)) illegal (isnt it?)
^^^^^^^
Error: [parser] unexpected token
```
## Documentation
The API is documented [here](http://smolkaj.github.io/nice-parser/nice_parser/).
The [example skeleton](example) should be self-explanatory.
## How to build
Ideally, use OCaml 4.08 or higher (for [beautiful error messages](https://github.com/ocaml/ocaml/pull/2096)).
All required dependencies can be installed using the [opam](http://opam.ocaml.org) package manager.
The project can be built using [dune](https://dune.build).
```
opam install . --deps-only --with-test
dune build
dune runtest
```
## Suggestions and Improvements
Suggestions and changes are welcome. Please submit pull requests, or open issues.