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Comment by benj111 | Hacker News Reader

>Assembly is usually considered the perfect example of such an “untyped” language.

>However, every instruction has a set of valid forms. Each form dictates the kind of each operand (register, memory, immediate, label), the class of each register...

So if I lea that means the type is pointer. If I add it's an int. If I print it's some kind of char.

So it's about as typed as B. The untyped predecessor to c....

Will any errors get raised is you sign extend an unsigned int?

Yes you can enforce types the processor doesn't care though, and if you want to treat assembly as distinct, I can't think of any assembly language that enforced types.

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Assembly doesn’t have typed objects, it has typed instructions. It’s like checked exceptions in Java—you have to declare them in the type signature of the method, and the compiler enforces that they are either caught and handled, or also explicitly declared by the caller. The type declaration is all about possible side effects.

It’s an effect in the type system, not a data type or behavior.

Yes. But that's like saying B is typed.

If you give an untyped number to B's print function, it'll print the ASCII letter. That doesn't make B typed.

And this is being generous. Types in typed languages aren't just about the data, it's about what you can do with that data. If a function requires a pointer, it needs to know that that arbitrary collection of 1s and 0s is a pointer. Typing is the mechanism to enforce that. All (?) functions on all(?) languages assume, if they don't outright know, something about the type, so are all languages typed? And in that case why is the distinction at all meaningful?

You're talking about objects. I'm talking about integers, chars, pointers.

A 32bit register could be handed to sign extend, it could be used as pointer, used as an interrupt number, printed as a letter. The processor doesn't care. Assemblers typically don't care. Different things you do with that number imply that you are using it as a type, but nothing cares if you use a pointer as a system call number and then print is out as a utf32 character.

Generously I assume Bill is thinking of "register classes" as types, so it doesn't care that you're using LEA on an integer, just that you used one of the registers for which LEA is available and not say XMM0

Ultimately the proof is in the pudding. If I screw up some inline assembly in Rust the diagnostics aren't very good because Rust doesn't deeply understand the assembly, whereas obviously for other things they're excellent. If Odin's diagnostics are great because it actually understands these "templates" that's a meaningful benefit to programmers.

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