class Sass::Compiler::Host::FunctionRegistry

def function_call(function_call_request)
  oneof = function_call_request.identifier
  identifier = function_call_request.public_send(oneof)
  function = case oneof
             when :name
               @functions_by_name[identifier]
             when :function_id
               @functions_by_id[identifier]
             else
               raise ArgumentError, "Unknown FunctionCallRequest.identifier #{identifier}"
             end
  arguments = function_call_request.arguments.map do |argument|
    protofier.from_proto(argument)
  end
  success = protofier.to_proto(function.call(arguments))
  accessed_argument_lists = arguments.filter_map do |argument|
    if argument.is_a?(Sass::Value::ArgumentList) && argument.instance_variable_get(:@keywords_accessed)
      argument.instance_variable_get(:@id)
    end
  end
  EmbeddedProtocol::InboundMessage::FunctionCallResponse.new(
    id: function_call_request.id,
    success:,
    accessed_argument_lists:
  )
rescue StandardError => e
  EmbeddedProtocol::InboundMessage::FunctionCallResponse.new(
    id: function_call_request.id,
    error: e.full_message(highlight: @highlight, order: :top)
  )
end