Fix #182 - Add support for lintr

ale_linters/r/lintr.vim

@@ -0,0 +1,15 @@
+" Author: Michel Lang <michellang@gmail.com>, w0rp <devw0rp@gmail.com>
+" Description: This file adds support for checking R code with lintr.
+
+function! ale_linters#r#lintr#GetCommand(buffer) abort
+    return ale#path#BufferCdString(a:buffer)
+    \   . 'Rscript -e ' . ale#Escape('lintr::lint(commandArgs(TRUE))') . ' %t'
+endfunction
+
+call ale#linter#Define('r', {
+\   'name': 'lintr',
+\   'executable': 'Rscript',
+\   'command_callback': 'ale_linters#r#lintr#GetCommand',
+\   'callback': 'ale#handlers#gcc#HandleGCCFormat',
+\   'output_stream': 'both',
+\})