…ods. Refs Copilot-Language#564.

This adds functionality for implementing the class methods of `Struct` and
`Typed` using `GHC.Generics`. As such, one can now easily define instances of
these classes by deriving a `Generic` instance for the struct data type, i.e.,

```hs
data MyStructType = ...
  deriving Generic

instance Struct MyStructType where
  typeName = typeNameDefault
  toValues = toValuesDefault
  updateField = updateFieldDefault

instance Typed MyStructType where
  typeOf = typeOfDefault
```

This work is based off of an initial implementation by Marten Wijnja (@Qqwy)
from Copilot-Language#561. Unlike Copilot-Language#561, I do not yet change any of the default implementations
of any `Struct` or `Typed` methods. This is because several `Struct` instances
in the wild currently do not define implementations of `updateField`, and
moreover, they also do not define `Generic` instances for the corresponding
data types. As such, changing the default implementation of `updateField` to
use a `Generic`-based default would cause these instances in the wild to no
longer compile. We will explore changing the default implementations after a
suitable transition period.

Co-authored-by: Marten Wijnja <[email protected]>

…opilot-Language#564.

In the future, we plan to change the default implementation for `updateField`
such that it will require a `Generic` instance. This will break any existing
`Struct` instance that omits an implementation of `updateField` and also does
not define a `Generic` instance for the struct data type. Unfortunately, there
does not appear to be a way for GHC to warn about this combination of
properties, but we can at least warn about this in the `updateField` Haddocks.

…. Refs Copilot-Language#564.

Using recently added `Generic`-based implementations, much of the boilerplate
code needed to define `Struct` and `Typed` in the struct-related `copilot`
examples can be replaced with much simpler implementations. Note that I have
intentionally _not_ used `updateFieldDefault` in the `StructsUpdateField.hs`
example, as that example is intended to demonstrate how one would implement
`updateField` by hand.

This work is based off of an initial implementation by Marten Wijnja (@Qqwy)
from Copilot-Language#561.

Co-authored-by: Marten Wijnja <[email protected]>

…ods. Refs Copilot-Language#564.

This adds functionality for implementing the class methods of `Struct` and
`Typed` using `GHC.Generics`. As such, one can now easily define instances of
these classes by deriving a `Generic` instance for the struct data type, i.e.,

```hs
data MyStructType = ...
  deriving Generic

instance Struct MyStructType where
  typeName = typeNameDefault
  toValues = toValuesDefault
  updateField = updateFieldDefault

instance Typed MyStructType where
  typeOf = typeOfDefault
```

This work is based off of an initial implementation by Marten Wijnja (@Qqwy).

Note that I do not yet change any of the default implementations of any
`Struct` or `Typed` methods. This is because several `Struct` instances in the
wild currently do not define implementations of `updateField`, and moreover,
they also do not define `Generic` instances for the corresponding data types.
As such, changing the default implementation of `updateField` to use a
`Generic`-based default would cause these instances in the wild to no longer
compile. We will explore changing the default implementations after a suitable
transition period.

Co-authored-by: Marten Wijnja <[email protected]>

…opilot-Language#564.

In the future, we plan to change the default implementation for `updateField`
such that it will require a `Generic` instance. This will break any existing
`Struct` instance that omits an implementation of `updateField` and also does
not define a `Generic` instance for the struct data type. Unfortunately, there
does not appear to be a way for GHC to warn about this combination of
properties, but we can at least warn about this in the `updateField` Haddocks.

…. Refs Copilot-Language#564.

Using recently added `Generic`-based implementations, much of the boilerplate
code needed to define `Struct` and `Typed` in the struct-related `copilot`
examples can be replaced with much simpler implementations. Note that I have
intentionally _not_ used `updateFieldDefault` in the `StructsUpdateField.hs`
example, as that example is intended to demonstrate how one would implement
`updateField` by hand.

This work is based off of an initial implementation by Marten Wijnja (@Qqwy).

Co-authored-by: Marten Wijnja <[email protected]>