List all functions in a R source file

ls_functions.r

## List the functions in a file, or if not specified the global environment
##
## @param src an optional source file
##
## @return a character vector of function names
ls_functions <- function(src=NULL) {
  if (is.null(src)) {
    classes <-   sapply(ls(.GlobalEnv), function(x) class(eval(parse(text=x))))
  } else {
    e <- new.env()
    sys.source(src, env=e)
    classes <-   sapply(ls(e), function(x) class(eval(parse(text=x))))
  }
  return(names(which(classes=="function")))
}