citeproc

This library generates citations and bibliography formatted according to a CSL style. Currently version 1.0.2 of the CSL spec is targeted.

This library is a successor to pandoc-citeproc, which was a fork of Andrea Rossato's citeproc-hs. I always found it difficult to fix bugs in pandoc-citeproc and decided that implementing citeproc from scratch would give me a better basis for understanding. This library has a number of other advantages over pandoc-citeproc:

• it is much faster (as a rough benchmark, running the CSL test suite takes less than 4 seconds with this library, compared to 12 seconds with pandoc-citeproc)

• it interprets CSL more faithfully, passing more of the CSL tests

• it has fewer dependencies (in particular, it does not depend on pandoc)

• it is more flexible, not being tied to pandoc's types.

Unlike pandoc-citeproc, this library does not provide an executable. It will be used in pandoc itself to provide integrated citation support and bibliography format conversion (so the pandoc-citeproc filter will no longer be necessary).

How to use it

The main point of entry is the function citeproc from the module Citeproc. This takes as arguments:

• a CiteprocOptions structure (which currently just allows you to set whether citations are hyperlinked to the bibliography)

• a Style, which you will want to produce by parsing a CSL style file using parseStyle from Citeproc.Style.

• Optionally a Lang, which allows you to override a default locale,

• a list of References, which you can produce from a CSL JSON bibliography using aeson's decode,

• a list of Citations (each of which may have multiple CitationItems).

It yields a Result, which includes a list of formatted citations and a formatted bibliography, as well any warnings produced in evaluating the style.

The types are parameterized on a CiteprocOutput instance a, which represents formatted content in your bibliographic fields (e.g. the title). If you want a classic CSL processor, you can use CslJson Text. But you can also use another type, such as a pandoc Inlines. All you need to do is define an instance of CiteprocOutput for your type.

The signature of parseStyle may not be self-evident: the first argument is a function that takes a URL and retrieves the text from that URL. This is used to fetch the "indendent parent" of a dependent style. You can supply whatever function you like: it can search your local file system or fetch the content via HTTP. If you're not using dependent styles, you can get by with \_ -> return mempty.

The citeproc executable

If the package is compiled with the executable flag, an executable citeproc will be built. citeproc reads a JSON-encoded Inputs object from stdin (or from a file if a filename is provided) and writes a JSON-encoded Result object to stdout. This executable can be used to add citation processing to non-Haskell projects.

citeproc --help will summarize usage information. See the man page for more information.

Known bugs and limitations

Although this library is much more accurate in implementing the CSL spec than pandoc-citeproc was, it still fails some of the tests from the CSL test suite (58/845). However, most of the failures are on minor corner cases, and in many cases the expected behavior goes beyond what is required by the CSL spec.