The BNF Converter

What is the BNF Converter?

The BNF Converter is a compiler construction tool generating a compiler front-end from a Labelled BNF grammar. It is currently generating code for the target languages Haskell, Agda, C, C++, Java, and OCaml, as well as XML representations and Pygment syntax highlighters.

Given a Labelled BNF grammar the tool produces:

an abstract syntax implementation in the target language,
a case skeleton for the abstract syntax in the target language,
a pretty-printer in the target language,
an Alex, JLex, Ocamllex or Flex lexer generator file ,
a Happy, CUP, Ocamlyacc, Menhir, ANTLR or Bison parser generator file, and
a LaTeX file containing a readable specification of the language.

Download

Download (linux, mac, windows)

Install via stack from Stackage:

$ stack install BNFC

Install by Cabal from Hackage:

$ cabal install BNFC

Current development version (source repository on GitHub)

$ git clone https://github.com/BNFC/bnfc

News

Find the latest releases at https://github.com/BNFC/bnfc/releases.

BNFC release 2.9.5 2023-07-26

BNFC release 2.9.4.1 2022-12-17

BNFC release 2.9.4 2022-02-17

BNFC release 2.9.3 2021-10-01

BNFC release 2.9.2 2021-06-13

BNFC release 2.9.1 2021-03-01

BNFC release 2.9.0 2020-12-28

BNFC release 2.8.4 2020-10-10

BNFC release 2.8.3 2019-08-27

BNFC release 2.8.2 2018-11-04

Resources

Documentation

User Manual on Read the Docs (HTML)
Tutorial (a bit dated) (Files)
LBNF Reference Manual (also as PDF from 2005)
IPL book

Mailing list

Send questions, bug reports, usage news, etc, to our Google group.

Book

Implementing Programming Languages, a compiler book using BNFC.

A small example

Content of file Calc.cf:

-- Calc.cf: A grammar for arithmetical expressions
EAdd.	Exp	::=	Exp	"+"	Exp1	;
ESub.	Exp	::=	Exp	"-"	Exp1	;
EMul.	Exp1	::=	Exp1	"*"	Exp2	;
EDiv.	Exp1	::=	Exp1	"/"	Exp2	;
EInt.	Exp2	::=	Integer	;
coercions	Exp	2	;

Generate a parser (choose your backend):

bnfc --haskell -d   -m Calc.cf  &&  make
bnfc --agda    -d   -m Calc.cf  &&  make
bnfc --c            -m Calc.cf  &&  make
bnfc --cpp          -m Calc.cf  &&  make
bnfc --java         -m Calc.cf  &&  make
bnfc --java-antlr   -m Calc.cf  &&  make
bnfc --ocaml        -m Calc.cf  &&  make
bnfc --ocaml-menhir -m Calc.cf  &&  make

Run the test parser, generated e.g. with `--haskell`:

echo "1 + 2 * 3 - 4 / 5" | Calc/Test

BNFC functionality overview: BNFC code generator graph

Large examples

A grammar of C with an example C file.

A grammar of Alfa with an example Alfa file. (For more details, see the Alfa home page.)

A grammar of LBNF. It is at the same time an example LBNF file. The development version of this grammar is used in the implementation of the BNF Converter.

A grammar of Java 1.1 developed by Mike Rainey.

Authors

© Andreas Abel, Jonas Almström Duregård, Krasimir Angelov, Jean-Philippe Bernardy, Björn Bringert, Johan Broberg, Kyle Butt, Paul Callaghan, Grégoire Détrez, Markus Forsberg, Ola Frid, Peter Gammie, Thomas Hallgren, Pascal Hof, Simon Huber, Patrik Jansson, Kristofer Johannisson, Antti-Juhani Kaijanaho, Andreas Lööw, Justin Meiners, Kent Mein, Ulf Norell, Gabriele Paganelli, Michael Pellauer, Fabian Ruch, and Aarne Ranta 2002 - 2021.

License

Free software under the BSD 3-clause license.

Versions until 2.8.4 released under the GNU General Public License (GPL).