Commodities

Commodity is something which doesn’t have value without unit of measurement.

Examples of commodities are Helium, Gold, Silver, etc. All of these need an unit of measurement to make transaction record sensible (for example bar for Helium or oz for Gold).

Typically it is possible to transform commodity transactions between same commodity, but with different unit of measurement as long as there is well defined, constant conversion between those units.

For example: 42 Au oz → 1306.3460256 Au g → 1.3063460256 Au kg.

However, at the moment automatic commodity unit conversions are not supported with Tackler, but this is something which will be implemented in the future.

Commodity name (and combined unit) has to be a valid ID element (same rules applies as with account names).

For example, tracking Helium and Oxygen, you could use units He·bar and O2·bar:

   Gas:Tank·102  298 He·bar
   Gas:Tank·208  195 O2·bar

if your tank sizes are known and fixed.

Transactions with mixed commodities

Transactions with mixed commodities without value positions are not allowed.

Example of invalid mixed commodity transaction without value positions:

2017-05-01 'This is invalid
 Vault:Bullion 1 Au·g
 Vault:Bullion 4 Ag·g
 Assets:Cash

Mixed commodities must be converted to common commodity with value positions:

2017-05-01 'This is valid
 Vault:Bullion 1 Au·g @ 37.00 EUR
 Vault:Bullion 1 Ag·g @ 0.495 EUR
 Assets:Cash

About He·bar and O2·bar

Strictly speaking it doesn’t make sense to track gas pressures, because you have to also know tank size to figure out actual amount of gas.

So original example of He and O2 tanks could be written in following way:

2019-04-01 'Gas amount in liters
   Gas:Tank·102  298 He·bar @ 50 He·l
   Gas:Tank·208  195 O2·bar @ 50 O2·l

assuming that 50 liter storage tanks are used.

Example

For example see an accounting example for scuba diving Trimix Filling and Mixing Station. It demonstrates how to track different commodities and how to convert those commodities to monetary values.