Walk an R source file and run each command in RStudio automatically on a delay

walk_source.R

walk_source <- function(
  file = NULL, 
  delay = 1.5, 
  clear_each_cmd = TRUE,
  wait_for_press = TRUE,
  style = styler::tidyverse_style,
  record_screen = TRUE,
  ...
) {
  if (record_screen) {
    outside_env = environment()
    outside_env$screen_record_result = recordscreen::start_screen_record(...)
  }
  options("walk_source_cancel" = FALSE)
  if (is.null(file)) {
    txt <- rstudioapi::getSourceEditorContext()$contents
  } else {
    txt <- readLines(file, warn = FALSE)
  }
  calls <- rlang::parse_exprs(paste(txt, collapse = "\n"))
  i <- 0
  next_call <- function() {
    i <<- i + 1
    if (clear_each_cmd) cat("\f")
    text <- rlang::expr_text(calls[[i]])
    if (!is.null(style)) {
      text <- styler::style_text(text, style = style)
    }
    text <- paste(text, collapse = "\n")
    for (j in seq_len(nchar(text))) {
      if (isTRUE(getOption("walk_source_cancel", FALSE))) {
        stop("canceled")
      }
      if (substring(text, j, j) == " ") {
        Sys.sleep(runif(1, 0.1, 0.333))
      } else {
        Sys.sleep(runif(1, 0.01, 0.25))
      }
      rstudioapi::sendToConsole("", FALSE, focus = FALSE)
      rstudioapi::sendToConsole(
        code = substring(text, 1, j),
        execute = j == nchar(text)
      )
    }
    if (i < length(calls)) later::later(next_call, delay)
  }
  if (wait_for_press) {
    readline("Press enter when ready!")
    cat("\f")
  }
  later::later(next_call, delay)
  if (record_screen) {
    end_func = function() {
      # print("ending")
      # print(paste0("i: ", i))
      recordscreen::end_screen_record(outside_env$screen_record_result)
    }
    later::later(end_func, delay = delay * length(calls) + 10)  
  }
  if (record_screen) {
    return(outside_env$screen_record_result$outfile)
  }
}

walk_cancel <- function() {
  options("walk_source_cancel" = TRUE)
}

walk_cancel()