Constructors — nix-effects

Type constructors: Record, ListOf, Maybe, Either, Variant.

`Either`

Tagged union of two types. Accepts { _tag = "Left"; value = a; } or { _tag = "Right"; value = b; }.

`ListOf`

Homogeneous list type. ListOf Type checks that all elements have the given type.

Custom verifier sends per-element typeCheck effects with indexed context strings (e.g. List[Int][2]) for blame tracking. Unlike Sigma, elements are independent — no short-circuit. All elements are checked; the handler decides error policy (strict aborts on first, collecting gathers all).

`Maybe`

Option type. Maybe Type accepts null or a value of Type.

`Record`

Record type constructor. Takes a schema { field = Type; ... } and checks that a value has all required fields with correct types. Extra fields are permitted (open record semantics).

`Variant`

Discriminated union. Takes { tag = Type; ... } schema. Accepts { _tag = "tag"; value = ...; } where value has the corresponding type.