Shape Security uses a language called DEX1 to configure security policies used to defend enterprises against Botnet attacks. DEX is a purely functional, decidable, statically typed language designed to facilitate configuration and analysis. By design, it is not Turing-complete. The language does not permit recursion and has no explicit looping constructs. Iteration over finite collections is provided via list comprehensions. As a result, a program written entirely in DEX can never diverge or crash.

The talks introduce DEX. The talk will then list a number of feature of the language, from typing to null handling, and give an experience report on the usage and the past and foreseeable evolution of the DEX language.