We tokenize, and then do the simplest possible recursive descent.
We don't want to evaluate anything, so infix operators are out,
meaning no shunting yard or tree rearranging or LR(1) shenanigans
are necessary, just write the code.
If we want to 'peek', just take the next token, and pass it around
from that point on, until it can actually be consumed.
So far the interface to hz.erl is mostly unchanged, apart from prepare_aaci/1
Maybe prepare_aaci should be re-exported, but using it is exactly in line with the
'inconvenient but more flexible primitives' that hz_aaci.erl is meant to represent,
so, maybe that is a fine place to have to go for it, dunno.
Jarvis Carroll