Create and execute an Octave file

octave.R

#' Create and execute an Octave file 
#' 
#' This function creates 2 files in the working directory:
#' \itemize{
#'  \item{filename.m contains an Octave (Matlab) script}
#'  \item{filename.csv contains estimation results}
#'  }
#' Variables filename and 
#' allitems are currently used as mustache tag variables.
#' More information on the Mustache format:
#' https://github.com/mustache/mustache
#' See source near octavecommand to see how the replacement is done.
#' 
#' The output of Octave is sent to filename.log.
#' @param dtf a data frame containing at least an item column
#' @param octavecommand the octave command with optional mustache
#'        variables included
#' @param filename the name of the file without extension
#' @param path the path where csv data files are located
#' @param sleep waiting time after calling stata and before reading the csv result file
#' @param nblines number of lines to be expected in the result file
#' @return a dataframe containing estimation results
#' @export
octave <- function(dtf, octavecommand, filename,
                   path = "data-end/octave/",
                   sleep = 0.2, nblines = length(unique(dtf$item))){
    allitems <- paste0("'", paste(unique(fp$item), collapse = "','"), "'")
    resultfile <- paste0(path, filename, ".csv")
    if (file.exists(resultfile)){
        file.remove(resultfile)
    }
    ### Create an octave ".m" file
    octavefile <- file(paste0(path, filename, ".m"), "w")
    octavecommand %>% 
        gsub("\\{\\{filename\\}\\}", filename, .) %>%
        gsub("\\{\\{allitems\\}\\}", allitems, .) %>%
        cat(file = octavefile)
    close(octavefile)
    
    ### Execute the octave ".m" file
    basedir <- getwd()
    setwd(path)
    tryCatch(system2("octave",
                     c(paste0(filename,".m", "&")),
                     wait = TRUE),
             finally = setwd(basedir))
    # Didn't mannage to redirect stdout
    #                      stdout = paste0(filename,".log"),
    
    ### Read results from the csv file
    # Even with system2(wait = TRUE) the file is not created
    # before read.csv tries to read it
    # Therefore the while() instruction waits "sleep" seconds 
    # until the result file contains the expected
    # number of lines
    result <- data.frame()
    while(!file.exists(resultfile)) Sys.sleep(sleep)
    while(nrow(result) < nblines){
        Sys.sleep(sleep)
        tryCatch(result <- read.csv(resultfile, na.strings =".", as.is=TRUE),
                 warning = function(w) {
                     message(sprintf("Wait %s seconds for Octave to finnish writing csv file.", sleep))})
    }
    return(result)
}