It occurs to me at this point, that we are fast approaching the point where we need a typographical system for symbolizing general cryptocurrency concepts, similar to the formal systems used in symbolic logic and cryptography.
Maybe not this, precisely, but something like:
A→B : spend from A to B
A→O : A offers to spend to (i.e., buy from) anyone in the market (bid)
A←O : A offers to receive from (i.e., sell to) anyone in the market (ask)
I'm not sure what the other operators would be, but there are not many atomic concepts that need to be represented in the software. It is in the mixing that the complexity emerges.
An analogy here might be that from electrons, protons, and neutrons, we get elements, then chemistry, then biology, then economics.