Descriptions of all current learners in the software are described below. Each learner description includes all available keywords and a table summarizing the keywords and their argument types and bounds, where appropriate. From this information it is easy to write a learner specification for the actions which require a learner. In every case the learner name follows the learner keyword, separated by the customary whitespace. Keywords for the learner can be specified anywhere else on the command-line. It is possible for a learner to have keywords whose argument specifies one or more learners, for example with the super learner. The syntax used for such keywords is detailed in the keyword's description.