Get the field names, get or set certain fields of an JuliaObject.
fields(object)
# S3 method for class 'JuliaObject'
fields(object)
field(object, name)
# S3 method for class 'JuliaObject'
field(object, name)
field(object, name) <- value
# S3 method for class 'JuliaObject'
field(object, name) <- value