Combining specifications with and and or

clojure.core/and function and clojure.core/or function can be used to define a specification with multiple parts.

Conform to One or more specifications

A specification for residential address included either a house number or name. The clojure.core/or function allows either type of value to be used and conform to the specification.

(spec/def ::house-name-number (or string? int?))

Using spec/or then unique keys are required for each possible type of value. Keys are used to explain where a failure occurred if values do not conform to the specification.

(spec/def ::house-name-number (spec/or :string string?
                                       :number int?))

If specifications are uses as the options in the clojure.spec.alpha/or then those specification names are used as the keys to explain where failure to conform to the specification happened.

(spec/def ::social-security-id (spec/or ::social-security-id-uk
                                        ::social-security-id-usa))

Conform to all specifications

Create a composite specification using clojure.spec.alpha/and when all specifications should be conformed by the values

For an arranged banking overdraft limit, the value should be a positive number, that is an integer type and is less than 1000.

(spec/def ::arranged-overdraft-limit (spec/and pos? int? #(> 1000 %)))

If a value does not conform to any of the three specifications then the value fails the ::arranged-overdraft-limit specification.