Our decision to perform semantic construction with the aid of an abstract "glue" language (namely, 
-calculus) has pleasant consequences for grammar writing, so we would like to make the key combinatorial mechanisms (functional application and 
-conversion), available as black boxes to the grammar writer. From a grammar engineering perspective, this is a sensible thing to do: when writing fragments we should be free to concentrate on linguistic issues. In this Section we build the required black box.
In this section we build a ``black box'' making available the key combinatorial mechanisms required for working with -calculus: functional application and -conversion. Once we have such a black box available, we will be able to decorate our little DCG from Section 3.3.1 with extremely natural semantic construction code and start building representations. We will do this immediately in the rest of the section, and experiment with the resulting system.
As a testbed for our -conversion mechanism, the rank-grown implementation of our little natural language processing system will do. But afterwards, we shall take a step back, look at it again and re-structure it from the perspective of software engineering.