F#, OCaml, and Standard ML are the primary examples. It's surprising to me how ignored these languages are.
> it has so many simple features I love that I am sometimes surprised to find are missing in other languages
and a few other things that led me to believe they were unaware of discriminated unions. There was an implication that this was a unique or novel feature in Swift. It's like someone being excited about Python's pattern matching, thinking Python came up with it and wishing other languages had it when it's a watered down, less useful version of that found in languages it ignored for 30 years.
And it's not a judgement.
On the other hand, Rust also has first-class functions including closures. I do think that closures are a simple programming language feature, and I'm definitely surprised/put off when I write a language that doesn't have them (though these days I'm not sure there are any mainstream ones, now that Java and C++ both have them in the spec). Again it's precisely because I think of closures as the opposite of unique/novel that I am surprised at their absence. Why would I be surprised that a language does not have closures if I thought the Rust team just made them up?
So yes, I have no idea how one would conclude that someone's surprise at a simple feature being unavailable indicates that they think the feature is unique or novel, other than just being a knee-jerk reaction.
GP is probably talking about other mainstream languages or language that they regularly use such as javascript/typescript. It makes no sense to interpret this as "are missing in every other language ever invented."
You're right that plenty of people do ascribe Apple credit for inventions that they didn't invent, but there isn't enough context/detail here to conclude that has happened in this case.
I know this sounds very Emacs-fanatic of me, but it does get a bit tiring in the software world to have spent a lot of time in tool and language discovery only to be forced to work in a language that feels like a step backwards where people suddenly get excited or finally acknowledge the benefits of language designs that came before them. Really, this primarily reflects on Python, which I am currently having to use, and it feels like several step-functions down in capability, robustness, clean-ness, and several other qualitative and quantitative factors compared to something like F# and OCaml. There's a huge amount of "let's ignore other languages but then ad-hoc reinvent what they do in a mudball type of fashion". See Python's concurrency story for a particular egregious example. I am constantly bitten by things in Python that I'm honestly aware of no other language doing.
So it's probably fair to say I read in a bit to the above comment. I'm happy either way that people are appreciating ML-like features.
I've been doing Elixir for several years and have tried to get others excited about it, and the frustrating chicken and egg problem of "there's not a good pool of programmers to hire or ecosystem of libraries" often seems to kill it in its tracks. Especially painful when it comes to machine learning where Python has de-facto won.
The number of people who do this is far, far outweighed by the people who claim they see it all the time.
The day C# gets discriminated union types and true exhaustive pattern matching is the day I’ll have to think long and hard about how much more time I want to put into working with my beloved F#.
Example why it would be sweet. Compiler could spit out a warning if it's not sure the correct union type is being used. Like if the pet union has dog and cat. Cat has respawn set initially to 9. Dog doesn't have respawn. If you try to set respawn without checking if it's a cat compiler whines about it.