One thing I've realised is that even methods such as this require
error tracking. I won't implement it in the tokenise method as it's
not related to consuming the string per se but instead in the main method.
Note the overall size of this function in comparison to the C version,
as well as its clarity.
Of course, it is doing allocations in the background through
std::string which requires more profiling if I want to make this super
efficient™ but honestly the assembler just needs to work, whereas the
runtime needs to be fast.
The implementation for tokenise_symbol is already a lot nicer to look
at and add to due to string/string_view operator overloading of ==.
Furthermore, error handling through pair<> instead of making some
custom structure which essentially does the same thing is already
making me happy for this rewrite.
