Drop generator attributes

[hadley]

They don't appear to be used for anything, and interfere with code navigation.

[daroczig]

The purpose of the generator attribute is to keep track how the formatter/layout/appender fn was defined, and be able to report on that e.g. when the user checks what is being used:

library(logger)
log_appender()
#> appender_console

log_appender(appender_file(file = "/tmp/foobar"))
log_appender()
#> appender_file(file = "/tmp/foobar")

If we don't keep track of this, then the user will see something like:

function (lines) 
{
    if (is.finite(max_lines) | is.finite(max_bytes)) {
        fail_on_missing_package("R.utils")
        n_lines <- tryCatch(suppressWarnings(R.utils::countLines(file)), 
            error = function(e) 0)
        n_bytes <- ifelse(file.exists(file), file.info(file)$size, 
            0)
        if (n_lines >= max_lines || n_bytes >= max_bytes) {
            log_trace("lines: %s, max_lines: %s, bytes: %s, max_bytes: %s", 
                n_lines, max_lines, n_bytes, max_bytes, namespace = ".logger")
            log_trace("lines >= max_lines || bytes >= max_bytes: %s", 
                n_lines >= max_lines || n_bytes >= max_bytes, 
                namespace = ".logger")
            for (i in max_files:1) {
                if (i == 1) {
                  log_trace("killing the main file: %s", file, 
                    namespace = ".logger")
                  unlink(file)
                }
                else {
                  new <- paste(file, i - 1, sep = ".")
                  if (i == 2) {
                    old <- file
                  }
                  else {
                    old <- paste(file, i - 2, sep = ".")
                  }
                  if (file.exists(old)) {
                    log_trace("renaming %s to %s", old, new, 
                      namespace = ".logger")
                    file.rename(old, new)
                  }
                  if (i > max_files) {
                    log_trace("killing the file with too many rotations: %s", 
                      new, namespace = ".logger")
                    unlink(new)
                  }
                }
            }
        }
    }
    log_trace("logging %s to %s", shQuote(lines), file, namespace = ".logger")
    cat(lines, sep = "\n", file = file, append = append)
}
<bytecode: 0x5f8022b5b078>
<environment: 0x5f8022b602a8>

But I'm open to solving this more elegantly.

[hadley]

Oh I missed where it was used. If you want to keep this behaviour, I think it would be a little easier to capture it when you use log_appender() etc. Alternatively it might be easier to keep the current behaviour but just set the generator attribute in a way that doesn't interfere with code search. I'll think about this a bit more.

[daroczig]

Usually, the generator is defined via deparse(match.call()), but you are right that it might be possible to capture how the fn was actually called one level up to log_config_setter (as that is being called from e.g. log_appender). I'll try to play with this tomorrow 👍

[hadley]

A simpler approach might just be to adopt a syntax like this:

generator <- function(x) attr(x, "generator")
`generator<-` <- function(x, value) {
  attr(x, "generator") <- value
  x
}

appender_void <- function(lines) {}
generator(appender_void) <- quote(appender_void())

[daroczig]

I've spent some time trying to capture the generator in log_config_setter (basically via match.call(definition = sys.function(-1), call = sys.call(-1))[[2]]), but failed miserably with edge cases e.g. when calling log_appender in do.call, so I think we need to keep tracking the generator close to the function.

The above generator setter/getter approach works for me, although I am not sure yet how to use that elegantly with the factory functions, such as appender_file that returns a function now -- should it need to store the fn in a variable, call the generator setter, and then return on a 3rd line?

[hadley]

I'll take a pass through with the generator approach so you can see what you think. It might possibly also need a set_generator() function so you can also use inline.