Documentation

When working with the HKD representation, it is useful to have a way to convert to and from our original type. To do this, we can:

• construct the original type from our HKD representation, and
• deconstruct the original type into our HKD representation.

As an example, we can try (unsuccessfully) to construct an (Int, Bool) tuple from an unpopulated partial structure.

>>> :set -XTypeApplications
>>> import Data.Monoid (Last)

>>> construct (mempty @(HKD (Int, Bool) Last))
Last {getLast = Nothing}

We can also deconstruct a tuple into a partial structure:

>>> deconstruct @[] ("Hello", True)
(,) ["Hello"] [True]

These two methods also satisfy the round-tripping property:

construct (deconstruct x) == [ x :: (Int, Bool, String) ]