// Product-type (also called: pair, tuple)

// A Product-type always has only two fields, called "left" and "right".
// Product-types of more fields (called Structs) can be constructed by nesting Product-types.

// In JS, all products are encoded in the same way:
export const newProduct = l => r => ({l, r});
export const getLeft     = product => product.l;
export const getRight    = product => product.r;