The common way of reading an R dataset consists on two steps:

* First, the file is parsed using the function parse_file. This provides a literal description of the file contents as a hierarchy of Python objects representing the basic R objects. This step is unambiguous and always the same. * Then, each object must be converted to an appropriate Python object. In this step there are several choices on which Python type is the most appropriate as the conversion for a given R object. Thus, we provide a default convert routine, which tries to select Python objects that preserve most information of the original R object. For custom R classes, it is also possible to specify conversion routines to Python objects.

The basic convert routine only constructs a SimpleConverter objects and calls its convert method. All arguments of convert are directly passed to the SimpleConverter initialization method.

It is possible, although not trivial, to make a custom Converter object to change the way in which the basic R objects are transformed to Python objects. However, a more common situation is that one does not want to change how basic R objects are converted, but instead wants to provide conversions for specific R classes. This can be done by passing a dictionary to the SimpleConverter initialization method, containing as keys the names of R classes and as values, callables that convert a R object of that class to a Python object. By default, the dictionary used is DEFAULT_CLASS_MAP, which can convert commonly used R classes such as data.frame and factor.