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A few nits: I would not put Scala in the ML category (I'm not sure about Rust). Haskell is, in-fact an ML. Racket is a Scheme. I would consider the actor mod

A few nits: I would not put Scala in the ML category (I'm not sure about Rust). Haskell is, in-fact an ML. Racket is a Scheme. I would consider the actor model to be more OO than FP.

darksaints 5y ago
Scala may be hybrid OO/FP, but Martin Odersky has been absolutely clear that Scala's primary functional programming design was inspired by ML. At various times in the past, he has referred to Scala as OCaml with a different object model. I believe I read a post on Reddit quite a few years back from Martin Odersky about how he originally intended to only have structural typing, a-la SML, but when the decision was made to implement Scala on top of the JVM, that nominal typing made it's way in, with an object model that was closer to Java than OCaml, for interop purposes. Rust's primary influence was ML. The compiler was originally written in OCaml. In fact, Graydon Hoare has commented about how he preferred OCaml's module-based polymorphism, but the Haskell advocates would never shut up about type classes so he eventually relented on that one single idea and implemented traits. But he held on to OCaml's ideas for almost everything else, at least until the point where he resigned his BDFL position. Haskell has some ML influence, but it received that influence via Miranda. Miranda deliberately diverged from ML in the operator emphasis, and execution (lazy vs eager). They both might have been considered at arm's length with the ML family right up until the point (1990ish) that Haskell decided to eliminate all unpure IO and adopt Monadic IO. There is almost no resemblance anymore, and the functional programming community is very cleanly divided: you're either in the ML camp or you're in the Haskell camp, unless you're one of the few Lisp weirdos sitting in the corner singing hippy songs. The actor model does have a lot of roots in functional programming (as well as logic programming), but you're right that it is also related to modern OO programming insofar as most modern OO languages inherited a ton from Smalltalk, which was a similar message-passing model. However, unlike Smalltalk, the actor-oriented languages rely on immutable state and pure state transition functions. That makes them functional languages at least in some respects.

A few nits: I would not put Scala in the ML category (I'm not sure about Rust). Haskell is, in-fact an ML. Racket is a Scheme. I would consider the actor model to be more OO than FP.

darksaints 5y ago

Scala may be hybrid OO/FP, but Martin Odersky has been absolutely clear that Scala's primary functional programming design was inspired by ML. At various times in the past, he has referred to Scala as OCaml with a different object model. I believe I read a post on Reddit quite a few years back from Martin Odersky about how he originally intended to only have structural typing, a-la SML, but when the decision was made to implement Scala on top of the JVM, that nominal typing made it's way in, with an object model that was closer to Java than OCaml, for interop purposes. Rust's primary influence was ML. The compiler was originally written in OCaml. In fact, Graydon Hoare has commented about how he preferred OCaml's module-based polymorphism, but the Haskell advocates would never shut up about type classes so he eventually relented on that one single idea and implemented traits. But he held on to OCaml's ideas for almost everything else, at least until the point where he resigned his BDFL position. Haskell has some ML influence, but it received that influence via Miranda. Miranda deliberately diverged from ML in the operator emphasis, and execution (lazy vs eager). They both might have been considered at arm's length with the ML family right up until the point (1990ish) that Haskell decided to eliminate all unpure IO and adopt Monadic IO. There is almost no resemblance anymore, and the functional programming community is very cleanly divided: you're either in the ML camp or you're in the Haskell camp, unless you're one of the few Lisp weirdos sitting in the corner singing hippy songs. The actor model does have a lot of roots in functional programming (as well as logic programming), but you're right that it is also related to modern OO programming insofar as most modern OO languages inherited a ton from Smalltalk, which was a similar message-passing model. However, unlike Smalltalk, the actor-oriented languages rely on immutable state and pure state transition functions. That makes them functional languages at least in some respects.