Construct a new UserDomain. Any two instances of an UserDomain are equal if their string descriptors are equal. Contains a function used to check if any value is a member of the domain.

Required features: honest-but-curious

Usage

user_domain(identifier, member, descriptor = NULL)

Arguments

identifier

A string description of the data domain.

member

A function used to test if a value is a member of the data domain.

descriptor

Additional constraints on the domain.

Value

Domain

Details

Why honest-but-curious?:

The identifier must uniquely identify this domain. If the identifier is not uniquely identifying, then two different domains with the same identifier will chain, which can violate transformation stability.

In addition, the member function must:

1. be a pure function

2. be sound (only return true if its input is a member of the domain).