BNFC
A compiler front-end generator.
https://bnfc.digitalgrammars.com/
| LTS Haskell 22.42: | 2.9.5 |
| Stackage Nightly 2024-11-21: | 2.9.5 |
| Latest on Hackage: | 2.9.5 |
BNFC-2.9.5@sha256:97152909bdf787791d760d167ed08bd7e6f0745408e03325f0878a857aaa83b6,9044Module documentation for 2.9.5
- BNFC
- BNFC.Abs
- BNFC.Backend
- BNFC.Backend.Agda
- BNFC.Backend.Base
- BNFC.Backend.C
- BNFC.Backend.CPP
- BNFC.Backend.Common
- BNFC.Backend.Haskell
- BNFC.Backend.HaskellGADT
- BNFC.Backend.Java
- BNFC.Backend.Java.CFtoAbstractVisitor
- BNFC.Backend.Java.CFtoAllVisitor
- BNFC.Backend.Java.CFtoAntlr4Lexer
- BNFC.Backend.Java.CFtoAntlr4Parser
- BNFC.Backend.Java.CFtoComposVisitor
- BNFC.Backend.Java.CFtoCup15
- BNFC.Backend.Java.CFtoFoldVisitor
- BNFC.Backend.Java.CFtoJLex15
- BNFC.Backend.Java.CFtoJavaAbs15
- BNFC.Backend.Java.CFtoJavaPrinter15
- BNFC.Backend.Java.CFtoVisitSkel15
- BNFC.Backend.Java.RegToAntlrLexer
- BNFC.Backend.Java.RegToJLex
- BNFC.Backend.Java.Utils
- BNFC.Backend.Latex
- BNFC.Backend.OCaml
- BNFC.Backend.Pygments
- BNFC.Backend.Txt2Tag
- BNFC.Backend.XML
- BNFC.CF
- BNFC.Check
- BNFC.GetCF
- BNFC.Lex
- BNFC.Lexing
- BNFC.License
- BNFC.Options
- BNFC.Par
- BNFC.PrettyPrint
- BNFC.Print
- BNFC.Regex
- BNFC.TypeChecker
- BNFC.Utils
The BNF Converter
What is the BNF Converter?
The BNF Converter (bnfc) is a compiler construction tool generating a compiler front-end from a Labelled BNF (LBNF) grammar. It is currently able to generate Haskell, Agda, C, C++, Java, and OCaml, as well as XML representations.
Given a LBNF grammar the tool produces:
- an abstract syntax implementation
- a case skeleton for the abstract syntax in the same language
- an Alex, Ocamllex, JLex, or Flex lexer generator file
- a Happy, Ocamlyacc, Menhir, ANTLR, CUP, or Bison parser generator file
- a pretty-printer as a Haskell/Agda/C/C++/Java/Ocaml module
- a Latex file containing a readable specification of the language
More information: http://bnfc.digitalgrammars.com/
Installation
Some binaries are available at https://github.com/BNFC/bnfc/releases.
Installation from the Haskell sources is possible via stack or cabal.
Installation via stack (recommended)
You need a running installation of stack. To install and run the latest version of bnfc from stackage, enter at the command line:
stack install BNFC
bnfc --help
Installation via cabal
You need a running installation of a recent version of GHC and Cabal, most easily available via the GHCup. To install bnfc from hackage, enter at the command line:
cabal install BNFC
bnfc --help
Installing the development version
To install the development version of bnfc with the latest bugfixes (and regressions ;-)):
git clone https://github.com/BNFC/bnfc.git
cd bnfc/source
and then either
cabal install
or
stack install --stack-yaml stack-8.10.7.yaml
(replace 8.10.7 with your GHC version, and if you want to build with
your installed GHC then add flag --system-ghc).
Mini tutorial
-
Build a first parser in 5 min (Haskell backend):
-
In a fresh directory, prepare a grammar file
Sum.cfwith the following content:EInt. Exp ::= Integer; EPlus. Exp ::= Exp "+" Integer; -
Build a parser (in Haskell) with bnfc:
bnfc -d -m Sum.cf && makeThe
makestep needs the Haskell compiler GHC, the lexer generator alex and the parser generator happy (all included in the GHC installation). -
Inspect the generated files in directory
Sum. -
Test the parser.
echo "1 + 2 + 3" | Sum/Test
-
-
Try the C-family backends. (The prerequisites, GNU C(++) compiler (
gcc/g++), lexer generatorflexand parser generatorbison, are usually present):bnfc --c -m -o sum-c Sum.cf && make -C sum-c && echo "1 + 2 + 3" | sum-c/TestSum bnfc --cpp -m -o sum-cpp Sum.cf && make -C sum-cpp && echo "1 + 2 + 3" | sum-cpp/TestSum -
Try the other backends:
Option Backend --javaRequires Java, JLex or JFlex, and CUP. --java-antlrRequires ANTLR. --ocamlRequires OCaml, ocamllexandocamlyacc.--ocaml-menhirUses menhir instead of ocamlyacc.--agdaProduces Agda bindings to the parser generated for Haskell. --pygmentsProduces a lexer definition for the Python highlighting suite Pygments.
Documentation
https://bnfc.readthedocs.org/en/latest/
Support
You can discuss with us issues around bnfc on our mailing list [email protected].
For current limitations of bnfc, or to report a new bug, please consult our issue tracker.
Contribute
- Issue Tracker: https://github.com/BNFC/bnfc/issues
- Source Code: https://github.com/BNFC/bnfc
- Haskell coding style guide: https://github.com/andreasabel/haskell-style-guide/
- Some pull request etiquette:
- Document, document, document! (See style guide)
- Include test cases that cover your feature.
- Include changelog entry.
- More etiquette: E.g. https://gist.github.com/mikepea/863f63d6e37281e329f8
License
The project is licensed under the BSD 3-clause license.
BNFC versions until 2.8.4 released under the GNU General Public License.
Example uses of the BNF Converter
In research:
- NASA’s OGMA tool uses LBNF for its grammars, e.g. for a subset of C 99.
In teaching:
- Course Programming Language Technology at Chalmers / Gothenburg University.