In mathematical theory, the variant type is actually the theoretical opposite of a "struct" type. Mathematicians know this through the functions that apply to e

In mathematical theory, the variant type is actually the theoretical opposite of a "struct" type. Mathematicians know this through the functions that apply to each type. Simply inverting the direction of functions that describe a "struct" type creates a structure that exactly describes a variant type. The theory points to opposites but language writers, unaware of theory, more often than not leave out the critical primitive that should be intrinsic to all programming languages.