• PoolloverNathan@programming.dev
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          9 months ago

          You can’t random-access an iterator and use it again later. Can Rust compute the value of calling a function an infinite number of times?

          — former rustacean

          • Lauchmelder@feddit.de
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            9 months ago

            it can compute how often I needed to compute the value of calling a function an infinite number of times.

            println!("0");
            
            • PoolloverNathan@programming.dev
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              9 months ago

              If you’ve used a parser library’s recursive parser, you have infinite calls right there. If it supplies a recursive-parser function, that function is a type-limited equivalent to fix, which performs the infinite call operation. Your Rust library most likely implements recursion using hidden mutability, but in Haskell, your parsers can remain infinitely-recursive while still referencing themselves and immutable.

              Also, we get to ask people if they know what a monad is.

          • anton@lemmy.blahaj.zone
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            9 months ago

            You can’t random-access an iterator and use it again later.

            If your specific use case really needs random access to a list while lazy computing the elements just wrap them in Lazy and put them in a vector.

            Can Rust compute the value of calling a function an infinite number of times?

            The return type of an infinitely recursive function / infinite loops is ⊥, a type that by definition has no values. (Known in rust as !)