dry-rb - dry-logic v1.2 - Custom predicates

Custom predicates

Define custom predicates using the predicate method. Use the build in builder to evaluate and define your predicate.

extend Dry::Logic::Builder

build do
  predicate :divisible_with? do |num, input|
    (input % num).zero?
  end
end

Then create your predicate

is_divisible_with_ten = build do
  divisible_with?(10)
end

Here, 10 represents the first argument num to divisible_with?.

# 10 & 5 is passed as {input} to your method
is_divisible_with_ten.call(10).success? # => true
is_divisible_with_ten.call(5).success? # => false