Aside from Lisps being yet again an example of "Simpsons already did it.", there are also other examples and projects that go roughly into this direction. Like

Aside from Lisps being yet again an example of "Simpsons already did it.", there are also other examples and projects that go roughly into this direction. Like Roc[0]. Tim Sweeney[1] seems to be working on integrating functional programming into games development, which is highly competitive and very performance sensitive. John Carmack also has been advocating for using functional programming techniques in game development (partially). Generally I think FP has a bit of a misguided bad rep when it comes to performance. What makes code slow is indirection that a compiler cannot reason about and work that doesn't need to be done. There are FP techniques that can help a compiler or CPU to generate/transform efficient code and ones that can confuse them so to speak. Needless mutation can sometimes lead to bad code as well (from a compiler or CPU perspective), because it solidifies control. Functional programming is fundamentally a constraint, computers, interpreters and so on like constraints, because they can then go about shuffling around stuff without breaking those constraints if that makes sense. [0] https://www.roc-lang.org/ https://www.roc-lang.org/ [1] https://en.wikipedia.org/wiki/Tim_Sweeney_(game_developer) https://en.wikipedia.org/wiki/Tim_Sweeney_(game_developer)