RJpaper/magrittr/R/freduce.R

In hojsgaard/doBy: Groupwise Statistics, LSmeans, Linear Estimates, Utilities

#' Apply a list of functions sequentially
#'
#' This function applies the first function to \code{value}, then the
#' next function to the result of the previous function call, etc. 
#' 
#' @param value initial value.
#' @param function_list a list of functions.
#' @return The result after applying each function in turn.
#'
#'
#' @export
freduce <- function(value, function_list)
{
  k <- length(function_list)
  if (k > 1) {
    for (i in 1:(k - 1L)) {
      value <- function_list[[i]](value)  
    }
  }
  value <- withVisible(function_list[[k]](value))
  if (value[["visible"]]) value[["value"]] else invisible(value[["value"]])
}