18 Partial Domains

      18.1 A Non-Solution

      18.2 Exceptions

      18.3 The Option Type

      18.4 Total Domains, Dynamically

      18.5 Total Domains, Statically

      18.6 Summary

      18.7 A Note on Notation

    19 Staging

    20 Orderability and Hashing

      20.1 Ordering and Equality

      20.2 Remembering Where We Came From

      20.3 Hashing in Practice

    21 Queues from Lists

      21.1 Using a Wrapper Datatype

      21.2 Combining Answers

      21.3 Using a Picker

      21.4 Using Tuples

      21.5 A Picker Method