Add ktlint support (without formatting) for kotlin filetype (#610)

* Add ktlint support (without formatting) for kotlin filetype

* Fix code style and refactor to use ALE utility functions (GetMatches)

* Remove options for configuration file

* Refactor: Rename exec variable and use ale#Set for variable configuration

1 files changed, 54 insertions, 0 deletions

diff --git a/ale_linters/kotlin/ktlint.vim b/ale_linters/kotlin/ktlint.vim
new file mode 100644
index 00000000..f474e845
--- /dev/null
+++ b/ale_linters/kotlin/ktlint.vim
@@ -0,0 +1,54 @@
+" Author: Francis Agyapong <francisagyapong2@gmail.com>
+" Description: Lint kotlin files using ktlint
+
+call ale#Set('kotlin_ktlint_executable', 'ktlint')
+call ale#Set('kotlin_ktlint_rulesets', [])
+call ale#Set('kotlin_ktlint_format', 0)
+
+
+function! ale_linters#kotlin#ktlint#GetCommand(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'kotlin_ktlint_executable')
+    let l:file_path = expand('#' . a:buffer . ':p')
+    let l:options = ''
+
+    " Formmatted content written to original file, not sure how to handle
+    " if ale#Var(a:buffer, 'kotlin_ktlint_format')
+    "     let l:options = l:options . ' --format'
+    " endif
+
+    for l:ruleset in ale#Var(a:buffer, 'kotlin_ktlint_rulesets')
+        let l:options = l:options . ' --ruleset ' . l:ruleset
+    endfor
+
+    return l:executable . ' ' . l:options . ' ' . l:file_path
+endfunction
+
+function! ale_linters#kotlin#ktlint#Handle(buffer, lines) abort
+    let l:message_pattern = '^\(.*\):\([0-9]\+\):\([0-9]\+\):\s\+\(.*\)'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:message_pattern)
+        let l:line = l:match[2] + 0
+        let l:column = l:match[3] + 0
+        let l:text = l:match[4]
+
+        let l:type = l:text =~? 'not a valid kotlin file' ? 'E' : 'W'
+
+        call add(l:output, {
+        \   'lnum': l:line,
+        \   'col': l:column,
+        \   'text': l:text,
+        \   'type': l:type
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('kotlin', {
+\   'name': 'ktlint',
+\   'executable': 'ktlint',
+\   'command_callback': 'ale_linters#kotlin#ktlint#GetCommand',
+\   'callback': 'ale_linters#kotlin#ktlint#Handle',
+\   'lint_file': 1
+\})