tl;dr - Arc comes with a DSL designed for just the sort of problem described in the Arc Challenge. What really matters is the ability to create DSLs.
I worry that the challenge will eventually be dominated by over-specialized DSL's. Arc may have libraries that are particularly beneficial to accomplishing this challenge, but the functions and macros used to do so are not of a wholy different "language" from those used in everyday arc prgramming.
Hi Daniel, can you give us some examples of the sorts of DSLs you're playing with? The title ("Answering the arc challenge") led me to expect code snippets.