Rmd snippet that translates itself into Rpres

gistfile1.r

[...]

```{r, include=FALSE}
RMDtoRpres <- function(fname){
  require(stringr)
  text <- readLines(fname, encoding="UTF-8")
    text <- paste(text, collapse="\n")
    author   <- str_replace_all(str_extract(text,'author: ".*?\n'),'["\n]',"")
    date     <- str_replace_all(str_extract(text,"date: '.*?\n"),'["\n]',"")
    title    <- str_replace(str_replace_all(str_extract(text,'title: ".*?\n'),'["\n]',""),"title: ","")
    subtitle <- str_replace(str_replace_all(str_extract(text,'subtitle: .*?\n'),'["\n]',""),"subtitle: ","")
    text     <- str_replace(text, "---\n.*?---\n", 
                  paste0(str_replace(title, ".Rmd", ""), 
                    "\n=============\n", author, "\n",date, "\n\n", subtitle, "\n\n"))
    rule <- "\n## .+?\n"
    while(str_detect(text, rule)){
      replacement <- paste0( str_replace(str_extract(text, rule), "## ",""), "=============\n")
      text <- str_replace(text, rule, replacement)
    }
  writeLines(text, str_replace(fname, "\\.Rmd", ".Rpres"), useBytes=TRUE)
}
fname <- "session1.Rmd"
RMDtoRpres(fname)
```

[...]