Simplified roxygen style documentation for data frames

document_table.R

#' Build out an empty itemization table for a data frame
#'
#' @param x data.frame or tibble
#' @return character string, but it is printed, too
itemize_table <- function(x){
  klass <- sapply(x, function(x) class(x)[[1]])
  varnames <- names(klass)
  s <- c("\\itemize{",
         sprintf("  \\item{%s %s }", varnames, klass),
         "}")
  cat(s, sep = "\n")
  invisible(s)
}

#' Build out an empty enumeration table for a data frame
#'
#' @param x data.frame or tibble
#' @return character string, but it is printed, too
enumerate_table <- function(x){
  klass <- sapply(x, function(x) class(x)[[1]])
  varnames <- names(klass)
  s <- c("\\enumerate{",
         sprintf("  \\item{%s %s }", varnames, klass),
         "}")
  cat(s, sep = "\n")
  invisible(s)
}


#' Build out an empty description table for a data frame
#'
#' @param x data.frame or tibble
#' @return character string, but it is printed, too
describe_table <- function(x){
  klass <- sapply(x, function(x) class(x)[[1]])
  varnames <- names(klass)
  s <- c("\\describe{",
         sprintf("  \\item{%s}{%s }", varnames, klass),
         "}")
  cat(s, sep = "\n")
  invisible(s)
}

#' Build out empty table documentation for a data frame
#'
#' @param x data.frame or tibble
#' @param form charcater, one of 'itemize', "enumerate" or "describe"
#' @return character string, but it is printed, too
#' @examples
#' \dontrun{
#'  > document_table(iris)
#'  # \itemize{
#'  #   \item{Sepal.Length numeric }
#'  #   \item{Sepal.Width numeric }
#'  #   \item{Petal.Length numeric }
#'  #   \item{Petal.Width numeric }
#'  #   \item{Species factor }
#'  # }
#' }
document_table <- function(x, form = c("itemize", "enumerate", "describe")[1]){
  s <- switch(tolower(form[1]),
         "itemize" = itemize_table(x),
         "enumerate" = enumerate_table(x),
         "describe" = describe_table(x),
         stop("form not known:", form[1]))
  invisible(s)
}