Oh I think I see what you mean now, you're talking about the encoding of the Torque source code that gets fed into the assembler. To be honest I'd never really considered anything other than UTF-8, the parsing is all implemented in Rust which requires strings to be valid UTF-8 anyway. Are you wanting to write Torque code with a non-Unicode text editor, or are you thinking about how the document encoding affects the handling of string literals inside the assembler?

Some kind of table syntax would be useful for character mappings, but I'm not sure what it'd look like or if it'd be applicable outside of dealing with characters. I'll think more on that.