This allows a little bit more of abstraction: we can store other data in the
tree, without having to store it in a specific node (e.g. the variables map,
which is still unused). It also adds a few typehints, and specializes
the return value of eval'ing the AST: previously, it was the one of
evalNode, which wasn't guaranteed to be an AFPData. Now we have this
guarantee. Last but not least, we can now measure runtime metrics for
evalTree, which doesn't recurse.
Bonus: fix a check in the old parser, which used the wrong variable when
reporting outofbounds errors.
Change-Id: Iff806793b1d968e9bb6220f1459f3d0ac587c7da
Arrays were introduced with the name "lists". While it **may** look
user-friendlier and so on, it actually uses a wrong name: lists are
different from arrays. I ran a grep and I should've replaced
every occurrence, plus everything seems to work, however a double check
wouldn't be bad.
Change-Id: I6a858f02f5dd9250ba7e1abf9c6422fd98758c9e
