R/1-duration-to-value.R

In flujoo/gm: Create Music with Ease

#' @keywords internal
#' @export
to_value.Duration <- function(x) {
  to_value_base(x) *
    # Convert tuplet ratios to value
    prod(vapply(x$ratios, to_value_ratio, numeric(1)))
}


to_value_base <- function(base) {
  # Convert duration type to value
  duration_types$value[duration_types$name == base$type] *
    # Convert number of dots to value
    sum(2^(-(0:base$dot)))
}


to_value_ratio <- function(ratio) {
  take <- ratio$take

  if (is.null(take)) {
    1 / ratio$n

  } else {
    to_value_base(take) / to_value_base(ratio$unit) / ratio$n
  }
}