Dynamically set parameters in define_method - ruby

Question

I have a class method ::add_method(name, params = {}) that creates an instance method with define_method.
I need the parameters of the defined method to be keyword arguments depending on the params.
class Whatever
def self.add_method(name, params = {})
# do something with params
define_method name do |?|
# some business
end
end
end
The goal is that when the ::add_method is called with:
params = {
foo: { required: false, default: 0 },
bar: { required: true }
}
Whatever.add_method(:hello, params)
then it creates this method:
def hello(foo: 0, bar:)
# some business
end
Nota bene: this is not the real business, I've over simplified it so the question is easier to understand.

Answer 1

So as advised I went to class_eval.
class Whatever
class << self
def add_method(name, parameters = {})
class_eval <<-RUBY, __FILE__, __LINE__ + 1
def #{name}(#{method_parameters(parameters)})
#{method_body(parameters)}
end
RUBY
end
# method_parameters({
# foo: { required: false, default: 0 },
# bar: { required: true }
# })
# => "foo: 0, bar:"
def method_parameters(parameters)
parameters.map do |key, options|
value = options[:required] ? '' : " #{options[:default] || 'nil'}"
"#{key}:#{value}"
end.join(', ')
end
# method_parameters({
# foo: { required: false, default: 0 },
# bar: { required: true }
# })
# => "[foo, bar]"
def method_body(parameters)
"[#{parameters.keys.map(&:to_s).join(', ')}]"
end
end
end
params = {
foo: { required: false, default: 0 },
bar: { required: true }
}
Whatever.add_method(:hello, params)
Whatever.new.hello(bar: true) # => [0, true]
Whatever.new.hello(foo: 42, bar: true) # => [42, true]
Whatever.new.hello # missing keyword: bar (ArgumentError)