Sum Types, Type Disjunctions and Possible Alternatives

[jrose (Jordan Rose)]

Previous discussion (I’m jumping you to the middle of the original thread out of ego but also in the interest of clarifying which kind of disjunctive type you’re looking for):

Adding Either type to the Standard Library

As a (semi-)aside, the "union type" on the commonly rejected changes list is about a type with implicit conversions, which is a little different from the anonymous-but-explicit enum/union/sum types advocated by Pointfree and others. I wish I could find a citation for how they'd complicate the type system, but I can't, although there's a little discussion way back in an early thread about Result and Either. TypeScript's union types allow accessing members common to all parts of the union. Swift …