Abstract : In this article we present GenI, a chart based surface realisation tool implemented in Haskell. GenI takes as input a set of first order terms (the input semantics) and a grammar for a given target language (e.g., English, French, Spanish, etc.) and generates sentences in the target language, whose semantic meaning corresponds to the input semantics. The aim of the article is not so much to present GenI or to describe how it is implemented. Rather, we will focus on the aspects of functional programming (higher order functions, monads) and Haskell (typeclasses) that we found important to its design.