[iainmerrick]

Thanks for that, I wasn’t fully aware of the history of ML! Very interesting (and very impressive that this is just one of Milner’s contributions).

I started with Haskell, where the main influence besides ML was Miranda. (If I remember correctly, Haskell was only created because Miranda was proprietary; similar to BitKeeper and Git.) I guess Miranda’s main innovation was lazy evaluation. That has certainly been influential but outside Haskell I don’t think it’s ever had widespread adoption in the same way as ML-style typing and type inference.

* Every responsible programming language designer could have taken on board ML's lessons sincen, and it's an interesting historical question why this did not happen.*

Agreed! But maybe it is happening, it’s just that it’s taken 30 years instead of the 5 or 10 one might have expected?

[Cladode]

Yes, Miranda was very expensive, had an onerous license and only ran on Unix, that's why researchers felt the need to create a free and open alternative.

Lazy evaluation was invented multiple times. First in theoretical studies of the lambda calculus by Wadsworth in 1971. Later, Friedman & Wise, and independently Henderson & Morris proposd a lazy Lisp, Turner (who later did Miranda) gave SASL a lazy semantics (SASL was eager initially). All three were from 1976, so it was clearly an idea in-the-air. SASL later evolved in to Miranda. Another of Miranda's innovations was to use combinators for graph reduction to implement the Miranda run-time.