Granite is a strict and untyped programming language under development with the goal of enhancing functional programming along a number of axes. It aims to provide a basis for general-purpose programming that is:

1. Parallelizable: Programs naturally incorporate deterministic parallelism in a manner remniscent of LVars.
2. Expressive: Programmers have access to both the rich data structures common in functional programming as well as cyclic data types via functional logic programming in the style of Datafun.
3. Compositional: It is easy to extend (mutually) recursive functions to support new cases using open recursion and a construct similar to the merge operator of Dunfield.

Perhaps surprisingly, these three aspects of language design are closely related: Granite’s design is emerging from the observation that at the heart of each of the above-mentioned lines of work lies a join-semilattice. Granite makes semilattice structure a first-class language feature. We describe several examples of this and discuss challenges that arise implementing the language.