[saagarjha]

No, that's not what Turing complete means. Turing complete means it can do an arbitrary computation, but "implementing Rust" usually means it needs to be able to take in a string of code and produce a binary, which means your program needs to have some way of actually doing that. Sure, you can encode the compiler into the Turing machine, but an arbitrary Turing-complete tarpit may not actually have the syntax to know what a string is. Usually the best you can do is encode the programming language into some form the machine can understand. (For example, with Fractran you'd encode your input as some sort of Gödel numbering before giving it to the program.)

[jfkebwjsbx]

Compiling is an arbitrary computation.

Encoding the inputs/outputs for a given TC system may be a pain, but that is irrelevant to expressiveness power.

[saagarjha]

Right, I'm not saying you can't put the compiler for the encoded input/outputs into the machine or that it's not expressive enough. I'm just saying that you'll have to encode stuff, it's not like traits somehow can magically give you a "compileToRust()" function that you pass the unmodified code into.

[jfkebwjsbx]

Yeah, but when someone mentions some system is TC they are not claiming input/output is easy to encode.

In fact, in most cases, when you hear the TC claim it is about an exotic system :)

[oh_sigh]

Fractran accepts any positive integer as an argument, and it is trivial to convert any, say, UTF8 encoded string to a positive integer.