Dhall language support (fixes #2820)

autoload/ale/dhall.vim

@@ -0,0 +1,21 @@
+" Author: toastal <toastal@protonmail.com>
+" Description: Functions for working with Dhall’s executable
+
+call ale#Set('dhall_executable', 'dhall')
+call ale#Set('dhall_use_global', get(g:, 'ale_use_global_executables', 0))
+call ale#Set('dhall_options', '')
+
+function! ale#dhall#GetExecutable(buffer) abort
+    return ale#Escape(ale#Var(a:buffer, 'dhall_executable'))
+endfunction
+
+function! ale#dhall#GetExecutableWithOptions(buffer) abort
+    let l:executable = ale#dhall#GetExecutable(a:buffer)
+
+    return l:executable
+    \   . ale#Pad(ale#Var(a:buffer, 'dhall_options'))
+endfunction
+
+function! ale#dhall#GetCommand(buffer) abort
+    return '%e ' . ale#Pad(ale#Var(a:buffer, 'dhall_options'))
+endfunction