Numis

This project aims to create a domain specific language for describing balance sheets.

It is heavily inspired by:

• Borja Clavero's paper on the 4 primitive balance sheet operations
• Various posts by Daniel H. Neilson on his "Soon Parted" substack
• Discussions about the nature of money at the mimbres school

Language Grammar

There are two types of statements: assertions and balance sheet operations

Assertions

An assertion allows you to make a claim about the initial conditions for the balance sheet.

The grammar goes <Name> <Operator> <Amount>

• Name: a single word that will be used to identify this agent, they will be given a balance sheet with assets and liabilities
• Operator: Either has or owes
• Amount: A number

Has

The has operator lets you assign an asset

A has 100

yields

A Assets	A Liabilities	Description
+100

Owes

The owes operator lets you assign a liability

A owes 100

yields

A Assets	A Liabilities	Description
	+100

Balance Sheet Operations

A balance sheet operation allows you to create a relationship between two agents.

The grammar goes <Payer> <Operator> <Amount> to <Payee> [as "<Description>"]

• Payer & Payee: a single word that will be used to identify this agent, they will be given a balance sheet with assets and liabilities
• Operator: Either assigns, issues, sets-off, novates
• Amount: A number
• Description: A textual description of the line item, the [] in the grammar indicate that this is optional

Assignment

The assigns operator lets you remove an asset from the payer and add an asset to the payee

A assigns 100 to B

yields

A Assets	A Liabilities	B Assets	B Liabilities	Description
-100		+100

Issuance

The issues operator lets you add a liability to the payer and add an asset to the payee

A issues 100 to B

yields

A Assets	A Liabilities	B Assets	B Liabilities	Description
	+100	+100

Set off

The sets-off operator lets you remove an asset from the payer and remove a liability from the payee

A sets-off 100 to B

yields

A Assets	A Liabilities	B Assets	B Liabilities	Description
-100			-100

Novation

The novates operator lets you add a liability to the payer and remove an asset from the payee

A novates 100 to B

yields

A Assets	A Liabilities	B Assets	B Liabilities	Description
	+100		-100

Descriptions

You can add a description by appending as "<some text>" to the end of a balance sheet operation

A assigns 100 to B as "a payment for goods and services"

yields

A Assets	A Liabilities	B Assets	B Liabilities	Description
-100		+100		a payment for goods and services

Comments

You can add single line comments with --

-- This is a comment
A assigns 100 to B as "a payment for goods and services"

A Full Example

-- The initial obligation
Taker assigns 100 to Payer as "export of goods"
Payer issues 100 to Taker as "taker opens foreign account"

-- The bill of exchange transaction
Deliverer assigns 100 to Taker as "payment in currency"
Taker assigns 100 to Deliverer as "bill of exchange"

-- The bill of exchange transfer from Deliverer to Payee
Deliverer assigns 100 to Payee as "bill of exchange"
Payee issues 100 to Deliverer as "deliverer opens foreign account"

-- The Payee gives bill of exchange to Payer
Payer assigns 100 to Payee as "payment in currency"
Payee sets-off 100 to Payer as "extinguish bill of exchange"

yields

Deliverer Assets	Deliverer Liabilities	Payee Assets	Payee Liabilities	Payer Assets	Payer Liabilities	Taker Assets	Taker Liabilities	Description
				+100		-100		export of goods
					+100	+100		taker opens foreign account
-100						+100		payment in currency
+100						-100		bill of exchange
-100		+100						bill of exchange
+100			+100					deliverer opens foreign account
		+100		-100				payment in currency
		-100			-100			extinguish bill of exchange