PDRT-SANDBOX is a Haskell library that implements Discourse Representation Theory (DRT), and its extension Projective Discourse Representation Theory (PDRT).
The implementation includes a translation from PDRT to DRT and First-order Logic, composition via different types of merge, and unresolved structures based on Montague Semantics, defined as Haskell functions.
Reference: Venhuizen, N. J. and Brouwer, H. (2014). PDRT-SANDBOX: An implementation of Projective Discourse Representation Theory. In: Rieser, V. and Muller, P. (Eds.), Proceedings of the 18th Workshop on the Semantics and Pragmatics of Dialogue, SemDial 2014 - DialWatt, pp. 249-251, September 1-3, Edinburgh, Scotland. [paper] [poster]