Tidy up your R code

Yihui Xie 2007-08-12

Update on 2012/03/04

Later the idea was turned into a package formatR and many details have been enhanced there. See the GitHub repo for details.

In the past I used to make use of source(my_source_file, echo = TRUE, prompt = "") to “tidy up” my code because it’s not convenient for me to type every space between operators, what’s more, I have no fixed rules to break a line or make a proper indent. Thus I need a function to automatically “tidy up” my code.

After I read the source code of the function source(), I quickly found that the actual workhorse is parse(), which can turn your code file into neat expressions, and the rest work is just to extract substrings. Here is a proof of concept:

tidy.source = function(file = choose.files()) {
   exprs = parse(file)
   for (i in 1:length(exprs)) {
       dep = paste(deparse(exprs[i]), collapse = "\n")
       dep = substring(dep, 12, nchar(dep) - 1)
       cat(dep, "\n")