Simon Peyton Jones

It was a piece of hardware that was designed by Symbolics to execute Lisp programs.

Lisp is a mostly functional programming language.

And so at the time I was, you know, in my early 20s, we were thinking, oh, crumbs, what would a piece of hardware look like that was primarily designed to execute functional programs?

Would it have a different kind of instruction set and architecture?

So

The newest we got to it, actually, was a big strand of work then that was called the MIT Dataflow project.

So Dataflow languages, functional languages, they're definitely the same kind of category.

And so the MIT had this great group led by Arvind called the MIT Dataflow group.

And they designed, in the end, a machine called Monsoon.

that was specifically designed to execute data flow programs, that is, functional programs.

It was based on a token store and matching and tokens flowing around and getting matched up and executing.

You might imagine data flowing through a graph.

When three arrives at a plus node and four arrives at the other input of the plus node, bam, you can fire that plus node, right?

And the hardware did all of that.

At a similar kind of time in England, my colleagues, Thomas Clark, Joe Stoy and others, built something called the SKI machine, SCIM.

There's a paper about this in the FDCA conference.

And SCIM was designed to execute SK combinators.

So at the time,

David Turner has written a lovely paper in which he described how to take lambda calculus programs and translate them into SK combinators.

So you can read about that in my book.