moved TokenList reference out of TokenFrontBack / some cleanups

[firewave]

No description provided.

[firewave]

This is in preparation because an upcoming PR will change the lifetime of TokenList which requires me to move it.

Please let's not get into a "you should not have references in objects" discussion. That will be addressed later (I thought our usage was fine but there was a fundamental misunderstanding on my side) - with the help of clang-tidy.

[pfultz2]

If a token has a reference back to the list then maybe it should be a weak_ptr or shared_ptr so we have better tracking of lifetimes.

Also it seems like the TokenList should construct the Token class instead since the lifetime is tied together. Although, I dont really follow what this code does, it seems quite confusing with a lot of pointer chasing going on.

[firewave]

If a token has a reference back to the list then maybe it should be a weak_ptr or shared_ptr so we have better tracking of lifetimes.

Yes - I will look into this when I review the usage of references in class.

Also it seems like the TokenList should construct the Token class instead since the lifetime is tied together. Although, I dont really follow what this code does, it seems quite confusing with a lot of pointer chasing going on.

One of the reasons why I wanted things more explicit and less cyclic/dependent.