Functional programming languages have a long association with graphs. In the
1990s, it was even thought that parallel graph-reduction
architectures could make functional programming languages much faster than their
imperative counterparts. Alas, that prediction mostly failed to materialize.
Even though graphs are still used as a theoretical formalism in order to define
and optimize functional languages (such as Haskell’s

spineless tagless graph-machine), they are still mostly compiled down to the same old
non-parallel assembly code that every other language uses. Now, two
projects —

Bend and

Vine — have sprung up attempting to change that, and prove that
parallel graph reduction can be a useful technique for real programs.