Cons provides a Prism between S and its first element A and tail S. It provides a convenient way to attach or detach elements to the left side of a structure S.
source of Prism and tail of Prism focus.
first element of Prism focus, A is supposed to be unique for a given S.
Provides a Prism between S and its first element A and tail S.
Prepend an element A to the first element of S.
Provides an Optional between S and its first element A.
Provides an Optional between S and its tail S.
Deconstruct an S to its optional first element A and tail S.