Implementing cryptocurrency assets using S4 classes

Now, we will implement our next abstraction with the least number of dependencies, Asset. We will implement it using S4, and it only depends on TimeStamp. We define its class using the standard methods shown before, and its attributes include email to identify what user an asset belongs to, a timestamp to identify the asset at a point in time, a name to know what asset we're dealing with, a symbol to identify the asset type within our system, a total to record how much of that asset a user has, and an address to identify what wallet the asset belongs to (a user may have several wallets for the same type of asset):

setClass(
    Class = "Asset",
    representation = representation(
        email = "character",
        timestamp = "character",
        name = "character",
        symbol = ...