Using a singleton type is nice because we can avoid writing conditional branches. Another side benefit is that performance can be greatly improved. An interesting example can be found in the ntuple function from Julia's Base package.
The ntuple function is used to create a tuple of N elements by applying a function over the sequence of 1 to N. For example, we can create a tuple of even numbers as follows:
The first argument is an anonymous function that doubles the value. Since we specified 10 in the second argument, it mapped over the range of 1 to 10 and gave us 2, 4, 6, ... 20. If we ...
