Changelog

Unreleased

1.3.0.0

JsonEither now takes a type-level list

JsonEither now accepts a type-level list of specs (JsonEither '[a, b, c]) instead of two arguments (JsonEither a b), so sum types with many branches no longer require a binary tree of nested JsonEithers. The structural type for JsonEither is nested Either: two or more branches map to Either (JStruct env a) (Either (JStruct env b) ...); a single branch maps to JStruct env spec (no sum wrapper). Use Left/Right for construction and pattern matching.

Migration guide

Specs (example: four alternatives)

Before:

JsonEither (JsonEither (JsonEither specA specB) specC) specD

After:

JsonEither '[specA, specB, specC, specD]

Patterns/construction

Note: The only difference in the pattern/construction may be how the Eithers are nested. The two examples below represent the same four alternatives with different Left/Right nesting; the JSON and types are equivalent.

Before (four branches):

Left (Left (Left val))
Left (Left (Right val))
Left (Right val)
Right val

After (same nesting with Left/Right; one branch = no wrapper):

Left val
Right (Left val)
Right (Right (Left val))
Right (Right (Right val))