Validate parameters against method signature

validate-parameters-against-method-signature.rb

def valid?(method, ...)
  signature = method.inspect
  pattern = %r{(?:\.|#)#{method.name}\(([^\)]*)\)}
  params = signature.match(pattern)[1]
  params_with_nil_default_values = params.gsub('...', 'nil')
  klass = Class.new
  klass.class_eval "def self.#{method.name}(#{params_with_nil_default_values})\nend\n"
  klass.public_send(method.name, ...)
  true
rescue ArgumentError => e
  p e
  false
end

def m1(a, b=2, c:, d: 4); end

p valid?(method(:m1), 1, c: 3)
# => true
p valid?(method(:m1), 1, 2, c: 3, d: 4)
# => true
p valid?(method(:m1), c: 3)
# => #<ArgumentError: wrong number of arguments (given 0, expected 1..2; required keyword: c)>
# => false
p valid?(method(:m1), 1, 2, 3)
# => #<ArgumentError: wrong number of arguments (given 3, expected 1..2; required keyword: c)>
# => false

def m2(*args); end

p valid?(method(:m2), a: 1)
# => true
p valid?(method(:m2), 1)
# => true
p valid?(method(:m2), 1, 2, 3, 4)
# => true

def m3(**kwargs); end

p valid?(method(:m3), a: 1)
# => true
p valid?(method(:m3), a: 1, b:2, c: 3, d: 4)
# => true
p valid?(method(:m3), 1)
# => #<ArgumentError: wrong number of arguments (given 1, expected 0)>
# => false