R/utils.r

In mpascucci/morexams: A wrapper for Rexams

check_folder <- function(folderName) {
  # check if the specified folder exists, otherwise throw an error
  # this function is private
  if (!dir.exists(folderName)) {
    stop(paste("The folder", folderName, "does not exist."))
  }
}

get_config_dir = function() {
  # Get the path of the config folder
  # this is a private function
  # If a folder named "Config" exist in the current
  # working path, then this is returned.
  if (dir.exists(DIR_CONFIG)) {
    DIR_CONFIG }
  else {
    system.file("Config", package = "morexams")
  }
}

#' Initialize the current folder with the default working three of morexams
#' Tutorial files are also copied in the working folder.
#'
#' @examples
#' library(morexams)
#' morexams_init()
morexams_init = function() {
  templates = list.files(system.file("Template", package = "morexams"),full.names = TRUE)
  file.copy(templates, getwd(), recursive = TRUE)
}

#' Create a configuration dir in the current folder
#' The configuration dir contains the LateX templates for the handwritten exams.
#' If the current working directory contains a Configuration folder its LateX templates are used.
#' This allows the modification of the templates
create_config_dir = function() {
  if (!dir.exists("Config")) {
    file.copy(system.file("Config", package = "morexams"), getwd(), recursive = TRUE)
  } else {
    cat("Config folder exists already in the current working folder")
  }
}

#' Return the length of the (significant) decimal part of x
#' It can be useful when writing exercices
count_decimals <- function(x) {
  x <- toString(x)
  split = unlist(strsplit(x, "\\."))
  if (length(split) != 2) {
    0
  } else {
    decimal_part = split[2]
    2**floor(log10(strtoi(decimal_part)))
  }
}
count_decimals(2.14)

#' Check that the automatic solution generation function is well written.
#' It is useful when writing exercices
#'
#' @param gen_sol function that generates the solution
#' @param params named list of arguments of gen_sol
#' @param solution the expected solution that should be calculated when calling gen_sol with the parameters params
check_solution <- function(gen_sol, params, solution) {
  precision = count_decimals(solution)
  if (
    !assertthat::are_equal(
      round(do.call(gen_sol, args=params), digits = precision),
      round(solution, digits=precision) )
  ) {
    stop("la fonction gen_sol ne passe pas le test.")
  }
}

#' Clean the console screen
clean_console <- function() {
  cat("\014")
}

#' Render a list as an HTML table
#' Useful to display data in an Rmarkdown exercice
array_to_HTMLTable <- function(c, columns) {
  s <- "<style>td.lex { padding-right: 0.5em; } </style>"
  s <- paste(s,"<table style='margin:auto;'>",sep="\n")
  col_n = min(columns, length(c))

  for (i in 1: length(c)) {
    if (i %% col_n == 1) {
      s <- paste(s,"<tr>", sep="")
    }

    td <- paste("<td class='lex'>",c[i],"</td>", sep="")
    s <- paste(s,td,sep=' ')

    if (i %% col_n == 0) {
      s <- paste(s,"</tr>",sep='')
      s <- paste(s,"\n",sep='')
    }
  }
  s <- paste(s,"</table>", sep="\n")
  s
}

#' Render a list as an markdown table
#' Useful to display data in an Rmarkdown exercice
array_to_MDTable <- function(c, columns) {
  col_n = min(columns, length(c))
  s <- paste(rep('', times = col_n+2), collapse="|")
  s <- paste(s,'\n',sep='')

  s <- paste(s,'|',sep='')
  l <- paste(rep('-', times = col_n), collapse="|")
  s <- paste(s,l,sep='')
  s <- paste(s,'|\n',sep='')

  for (i in 1: length(c)) {
    if (i %% col_n == 1) {
      s <- paste(s,"|", sep="")
    }
    s <- paste(s,c[i],sep='')
    s <- paste(s,'|',sep='')

    if (i %% col_n == 0) {
      s <- paste(s,"\n", sep="")
    }
  }
  s
}

#' Remove the specified folder.
#'
#' Check if the folder exists already.
#' If it exists, it will continue according to the
#' value of the OVERWRITE config variable
safe_mkdir <- function (folder) {
  if (!dir.exists(folder)){
    dir.create(folder, recursive=TRUE)
  } else {
    if (OVERWRITE) {
      answ <- readline(prompt="The output folder exists already, overwrite? [Y/n]")
      if (answ!="" & toupper(answ)!="Y"){
        stop("Operation aborted.")
      }
      # delete the output folder
      unlink(folder, recursive=TRUE)
      # create the output folder
      dir.create(folder)
    } else {
      # Stop program execution
      stop(paste("The folder", output_path, "exists already.", "Delete it or change the OVERWRITE config value to TRUE in config.R"))
    }
  }
}