new fixer elixir mix format

(only available in elixir > 1.6)

autoload/ale/fix/registry.vim

@@ -27,6 +27,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['javascript', 'typescript'],
 \       'description': 'Apply eslint --fix to a file.',
 \   },
+\   'mix_format': {
+\       'function': 'ale#fixers#mix_format#Fix',
+\       'suggested_filetypes': ['elixir'],
+\       'description': 'Apply mix format to a file.',
+\   },
 \   'format': {
 \       'function': 'ale#fixers#format#Fix',
 \       'suggested_filetypes': ['elm'],

autoload/ale/fixers/mix_format.vim

@@ -0,0 +1,17 @@
+" Author: carakan <carakan@gmail.com>
+" Description: Fixing files with elixir formatter 'mix format'.
+
+call ale#Set('elixir_mix_executable', 'mix')
+
+function! ale#fixers#mix_format#GetExecutable(buffer) abort
+    return ale#Var(a:buffer, 'elixir_mix_executable')
+endfunction
+
+function! ale#fixers#mix_format#Fix(buffer) abort
+    return {
+    \   'command': ale#handlers#elixir#GetExecutable(a:buffer)
+    \       . ale#fixers#mix_format#GetExecutable(a:buffer)
+    \       . ' format %t',
+    \   'read_temporary_file': 1,
+    \}
+endfunction

autoload/ale/handlers/elixir.vim

@@ -0,0 +1,5 @@
+call ale#Set('elixir_executable', '')
+
+function! ale#handlers#elixir#GetExecutable(buffer) abort
+    return ale#Var(a:buffer, 'elixir_executable')
+endfunction

test/fixers/test_elixir_fixer_callback.vader

@@ -0,0 +1,16 @@
+Before:
+  call ale#test#SetDirectory('/testplugin/test/fixers')
+
+After:
+  call ale#test#RestoreDirectory()
+
+Execute(The executable path should be correct):
+  call ale#test#SetFilename('../elixir-test-files/testfile.ex')
+
+  AssertEqual
+  \ {
+  \   'read_temporary_file': 1,
+  \   'command': 'mix format'
+  \     . ' %t',
+  \ },
+  \ ale#fixers#elixir#Fix(bufnr(''))