module T::Props::ClassMethods

def const(name, cls_or_args, args={})
  if (cls_or_args.is_a?(Hash) && cls_or_args.key?(:immutable)) || args.key?(:immutable)
    Kernel.raise ArgumentError.new("Cannot pass 'immutable' argument when using 'const' keyword to define a prop")
  end
  if cls_or_args.is_a?(Hash)
    self.prop(name, cls_or_args.merge(immutable: true))
  else
    self.prop(name, cls_or_args, args.merge(immutable: true))
  end
end