Merge pull request #403 from renkun-ken/styler-caching-readme

Update README.md

README.md

@@ -179,16 +179,5 @@ To further customize the formatting style, please refer to [Customizing styler](
 
 With [`styler`](https://github.com/r-lib/styler) v1.3, the formatting of top-level expressions
 can be cached by [`R.cache`](https://github.com/HenrikBengtsson/R.cache), which significantly improves the formatting performance by skipping the expressions that are known in cache to be already formatted. By default, the cache only works within the current session.
-To make it work across sessions, user must run the following command to perform a one-time authorization to create a permanent directory in user home in an *interactive* R session:
 
-```r
-R.cache::getCachePath()
-```
-
-The first time the command is run, it will ask user whether to create a permanent cache directory. Type `Y` and enter, the cache directory will be created, and then all cache operations will be done across sessions so that formatted expressions could be remembered globally.
-
-To check if a permanent directory is used or not, run the following command:
-
-```r
-styler::cache_info()
-```
+To make it work across sessions, set the R option `R.cache.rootPath` or environment variable `R_CACHE_ROOTPATH` to an existent path. For more details, see [styler caching](https://styler.r-lib.org/reference/caching.html).