There is a real argument to be made that quick prototyping in Rust is unintuitive compared to other languages, however it's definitely possible and does not even impact iteration speed all that much: the only cost is some extra boilerplate, without even needing to get into `unsafe` code. You don't get the out-of-the-box general tracing GC that you have in languages like Golang, Java/C# or ECMAScript, or the bignum-by-default arithmetic of Python, but pretty much every other basic facility is there, including dynamic variables (the `Any` trait).