## What changes were proposed in this pull request?
Currently, multi-dot separated variables in R is not allowed. For example,
```diff
setMethod("from_json", signature(x = "Column", schema = "structType"),
- function(x, schema, asJsonArray = FALSE, ...) {
+ function(x, schema, as.json.array = FALSE, ...) {
if (asJsonArray) {
jschema <- callJStatic("org.apache.spark.sql.types.DataTypes",
"createArrayType",
```
produces an error as below:
```
R/functions.R:2462:31: style: Words within variable and function names should be separated by '_' rather than '.'.
function(x, schema, as.json.array = FALSE, ...) {
^~~~~~~~~~~~~
```
This seems against https://google.github.io/styleguide/Rguide.xml#identifiers which says
> The preferred form for variable names is all lower case letters and words separated with dots
This looks because lintr by default https://github.com/jimhester/lintr follows http://r-pkgs.had.co.nz/style.html as written in the README.md. Few cases seems not following Google's one as "a few tweaks".
Per [SPARK-6813](https://issues.apache.org/jira/browse/SPARK-6813), we follow Google's R Style Guide with few exceptions https://google.github.io/styleguide/Rguide.xml. This is also merged into Spark's website - https://github.com/apache/spark-website/pull/43
Also, it looks we have no limit on function name. This rule also looks affecting to the name of functions as written in the README.md.
> `multiple_dots_linter`: check that function and variable names are separated by _ rather than ..
## How was this patch tested?
Manually tested `./dev/lint-r`with the manual change below in `R/functions.R`:
```diff
setMethod("from_json", signature(x = "Column", schema = "structType"),
- function(x, schema, asJsonArray = FALSE, ...) {
+ function(x, schema, as.json.array = FALSE, ...) {
if (asJsonArray) {
jschema <- callJStatic("org.apache.spark.sql.types.DataTypes",
"createArrayType",
```
**Before**
```R
R/functions.R:2462:31: style: Words within variable and function names should be separated by '_' rather than '.'.
function(x, schema, as.json.array = FALSE, ...) {
^~~~~~~~~~~~~
```
**After**
```
lintr checks passed.
```
Author: hyukjinkwon <gurwls223@gmail.com>
Closes#17590 from HyukjinKwon/disable-dot-in-name.
[[SPARK-8537] Add a validation rule about the curly braces in SparkR to `.lintr` - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-8537)
Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>
Closes#6940 from yu-iskw/SPARK-8537 and squashes the following commits:
7eec1a0 [Yu ISHIKAWA] [SPARK-8537][SparkR] Add a validation rule about the curly braces in SparkR to `.lintr`
Thank Shivaram Venkataraman for your support. This is a prototype script to validate the R files.
Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>
Closes#6922 from yu-iskw/SPARK-6813 and squashes the following commits:
c1ffe6b [Yu ISHIKAWA] Modify to save result to a log file and add a rule to validate
5520806 [Yu ISHIKAWA] Exclude the .lintr file not to check Apache lincence
8f94680 [Yu ISHIKAWA] [SPARK-8495][SparkR] Add a `.lintr` file to validate the SparkR files and the `lint-r` script