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rdf4h - An RDF library for Haskell

rdf4h is a library for working with RDF in Haskell.

For details see the GitHub project page:

http://robstewart57.github.io/rdf4h/

Supports GHC versions from 9.2.5 (stackage lts-20.11).

Development with Nix and direnv

To enter a development environment, you can use Nix and direnv which install all required software, also allowing you to use your preferred shell. Once installed, just run

$ direnv allow

and you'll have a working development environment for now and the future whenever you enter this directory.

This development environment allows to use either Stack or Cabal for building the software.

RDF formats

The coverage of the W3C RDF standards are:

Format	Parsing	Serialising
NTriples	complete	complete
Turtle	complete	complete
RDF/XML	complete	not supported

These results are produced with version 4.0 of this library.

These tests are run on the W3C unit tests for RDF formats: https://github.com/w3c/rdf-tests.

Feature requests

The parsers in this library parse large files/strings contents entirely before generating RDF triples. This doesn't scale for very large files. Implementing stream based RDF parsers would overcome this problem, e.g. by creating input streams enabling output streams in the io-streams library to consume triples on-the-fly during parsing. This is discussed here: https://github.com/robstewart57/rdf4h/issues/56#issuecomment-497892024 and https://github.com/robstewart57/rdf4h/issues/44#issuecomment-426054978
RDF/XML serialisation of RDF graphs.

Running tests

To run all the tests (parsers and the library API):

$ git submodule update --init --recursive
$ git submodule foreach git pull origin gh-pages
$ stack test --test-arguments="--quickcheck-tests 1000"

To run specific parser tests when bug fixing:

$ stack test --test-arguments="--pattern /parser-w3c-tests-ntriples/"
$ stack test --test-arguments="--pattern /parser-w3c-tests-turtle/"
$ stack test --test-arguments="--pattern /parser-w3c-tests-xml/"

Running benchmarks

To run the bencharks:

$ wget https://www.dropbox.com/s/z1it340emcreowj/bills.099.actions.rdf
$ gzip -d bills.099.actions.rdf.gz
$ stack bench