New custom action

[longfin]

#28 (comment)

After #27, there is no custom action to exemplify. 😢
IMO, Burn seems appropriate example. it needs only currency already we have, and consists of very simple codes.

[dahlia]

To clarify, TransferAsset still remains despite it's functionally replaced by Libplanet.Action.Sys.Tranfer. Its only raison d'être is for an example of composing a custom action.

IIUC @longfin is suggesting another custom action Burn, because it will be both functional and educational (as an example). FYI Burn is an administrative action to get rid of a certain amount of money from the entire economy (hence decrease its total supply).

Burn would follow the similar pattern with TransferAction in the big picture:

planet-node/PlanetNode/Action/TransferAsset.cs

Line 58 in c0064f2

return state.TransferAsset(Sender, Recipient, Amount);

At its core, TransferAction.Execute() forwards all its action values (properties) to IAccountStateDelta.TransferAsset() method. In the same manner, Burn.Execute() should forward all its action values to IAccountStateDelta.BurnAsset() method.