The #[derive(ProcBlock)] macro doesn't accept multiple inputs and outputs

[Michael-F-Bryan]

Someone was wanting to define a tokenizer proc block on Discord but didn't know how to tell the system they have multiple inputs and outputs. It turns out we've defined the proc-macro to only accept syntax for single inputs and outputs.

This is the error someone got when they tried what feels intuitive for the #[transform] attribute:

error: Unknown tensor element type
   --> /root/projects/hack/htn/bert/byte_input_conversion/src/lib.rs:205:39
    |
205 | #[transform(input = [u8; _], output = ([i32; 384], [i32; 384], [i32; 384]))]
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^