piker.accounting
________________
A subsystem for transaction processing, storage and historical
measurement.

synopsis
--------
The big question for any trader is this:

*what is the price that determines whether i take a loss or a gain on my
trade?*

In other words, at any given state of accounting your current assets,
what is the price between any 2 assets you've transacted that determines
at which price you can conduct **the next** transaction and know if you
are making or losing more (or less) of the *source* asset versus the
*destination* asset?

Let's do a very simple example:

> Joe wants to buy some tacos bc they're super hungo.
> Joe has a friend who also likes tacos but doesn't mind if they're fresh; he doesn't mind having day old tacos.
> Inflation is rampant and taco prices are trending up for no good reason besides everyone thinks prices are going up.
> Joe goes to the taco stand and buys 4 tacos at 25 mxn.
> This makes Joe's net cost `4 * 25 = 200` mxn.
> Joe eats 3 tacos and realizes that he can't finish the last, so he puts it in the fridge to save for the next day (since he owns a comal).
> The next day the price of tacos goes up to 30 mxn (for no good reason > besides the taco stand noticing Joe is a tourist and that > "inflation" is some thing that's used as an excuse for price changes).
> Joe's friend from before got lit up (like he does every morning) and msgs Joe to buy him 2 tacos for when he shows up in the late morning.
> Joe says "sure, but i also have a leftover if you want it, and I'm fasting today so you can have my sobras and i'll buy you a new one".
> The friend coughs a couple times, and says "yee no problem man, just make sure you get them"
>


Prior *suit* definitions:

- the canucks equiv of the IRS call this idea ["Adjusted cost base"](https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/personal-income/line-12700-capital-gains/definitions-capital-gains.html#Adjustedcostbase)


.pnl
----
BEP, the break even price: the price at which liquidating
a remaining position results in a zero PnL since the position was
"opened" in the destination asset.

PPU: price-per-unit: the "average cost" (in cumulative mean terms)
of the "entry" transactions which "make a position larger"; taking
a profit relative to this price means that you will "make more
profit then made prior" since the position was opened.
