I would argue that the Haskell language itself, through lazy evaluation, basically has built-in async/await support. Due to lazy evaluation, everything is a asy

I would argue that the Haskell language itself, through lazy evaluation, basically has built-in async/await support. Due to lazy evaluation, everything is a async/await - every time an expression is evaluated. In Python, you pass values around. In Haskell, you pass around descriptions of how to fetch a particular value, and then the runtime system makes sure it happens when/if it needs to. It's a bit like Excel. Every cell is a variable that contains an expression, which defines what this cell evaluates to. With that description in hand, it's a simple matter of not evaluating cells that are not in view, and marking an exception in the evaluation with #######. If it were Python, each cell could contain code that modifies other cells, and it would be impossible to make sense of anything.