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The (goblins actor-lib simple-mint) module provides an example
actor simulating a mint and currency. This is a Goblins
implementation of a
classic example
of object capabilities.
Constructor an actor which in turn constructs and returns
purses for its currency. A mint only has one method:
new-purse initial-balance spawns and returns a reference to a
new purse which holds initial-balance tokens.
A purse, on the other hand, has four methods:
get-balance: Return the current number of tokens in the purse.
sprout: Spawn and return a reference to a new empty
purse for this currency.
deposit amount src: Increase the number of tokens in this
purse by amount, decreasing the number of tokens in the
purse of the same currency src by the same amount.
get-decr: Return a procedure accepting one argument, an
amount of tokens to remove from this purse.
Spawn and return a reference to a new purse holding amount
tokens of the same type as the purse from-purse. Remove
the same numbers of tokens from from-purse.