class Dry::Logic::Rule::Value

def apply(input)
  predicate.(input)
end

def args
  @args ||= predicate.args
end

def arity
  @arity ||= predicate.arity
end

def call(input)
  if nulary?
    Logic.Result(predicate.(), self, input)
  else
    evaled = evaluate(input)
    result = apply(evaled)
    rule = result == true ? self : curry(evaled)
    Logic.Result(result, rule, input)
  end
end

def evaluate(input)
  input
end

def input
  predicate.args.last
end

def nulary?
  arity == 0
end

def to_ast
  [type, predicate.to_ast]
end

def type
  :val
end