dry-logic

Predicate logic and rule composition used by:

• dry-types for constrained types
• dry-validation for composing validation rules
• your project...?

Synopsis

require 'dry/logic'
require 'dry/logic/predicates'

include Dry::Logic

user_present = Rule::Key.new(Predicates[:key?], name: :user)

has_min_age = Rule::Key.new(
  Predicates[:key?]) & Rule::Value.new(:age, Predicates[:gt?].curry(18),
  name: :age
)

user_rule = user_present & has_min_age

user_rule.(user: { age: 19 })
# #<Dry::Logic::Result::Value success?=true input=19 rule=#<Dry::Logic::Rule::Value name=:age predicate=#<Dry::Logic::Predicate id=:gt?>>>

user_rule.(user: { age: 18 })
# #<Dry::Logic::Result::Value success?=false input=18 rule=#<Dry::Logic::Rule::Value name=:age predicate=#<Dry::Logic::Predicate id=:gt?>>>

License

See LICENSE file.