R/editR.R

In swarm-lab/editR: A basic Rmarkdown editor with instant preview

#' Edit Rmarkdown files with instant preview
#'
#' This function creates a GUI to edit \code{\link[rmarkdown:rmarkdown-package]{Rmarkdown}} 
#' documents and display an instant preview of the document as it is being 
#' written. Rmarkdown documents can be rendered directly from the GUI. 
#' 
#' @param file The path (as a character string) to an existing .Rmd/.md file, or 
#' to a new .Rmd/.md file. If the file does not exist, it will be created when the 
#' GUI starts.]
#' 
#' @return This function does not return anything.
#' 
#' @author Simon Garnier: \email{garnier@@njit.edu}, \link[https://twitter.com/sjmgarnier]{@@sjmgarnier}
#' 
#' @details If called from RStudio on Mac and Linux, it will open in the internal 
#' RStudio browser. If called from a terminal or on Windows, it will open in your 
#' default internet browser. editR should work without any problem with recent 
#' versions of most internet browsers. It is likely to break with older versions.
#' 
#' @examples
#' # Create and edit a new Rmarkdown document in the current working directory
#' editR("example.Rmd")
#' 
#' @export
#'
editR <- function(file = NULL, port = NULL) {
  require(tools)
  require(shiny)
  
  if (is.null(file)) {
    assign("md_name", NULL, envir=globalenv())
    assign("md_path", NULL, envir=globalenv())
  } else {
    ext <- tolower(file_ext(file))
    if (ext != "md" & ext != "rmd") 
      stop("'file' is not a .Rmd or .md file.")
    
    file <- suppressWarnings(normalizePath(file))
    
    md_name <- basename(file)
    md_path <- dirname(file)
    assign("md_name", md_name, envir=globalenv())
    assign("md_path", md_path, envir=globalenv())
  }
  
  app_path <- paste0(find.package("editR"), "/app")
  
  if (.Platform$OS.type == "windows") {
    if(!is.null(port)){
      runApp(app_path, port = port, launch.browser = TRUE)
    }else{
      runApp(app_path, launch.browser = TRUE)
    }
  } else {
    if(!is.null(port)){
      runApp(app_path, port = port)
    }else{
      runApp(app_path)
    }
  }
  
}