Add support for linting D code with DMD.

README.md

@@ -27,6 +27,7 @@ name. That seems to be the fairest way to arrange this table.
 | -------- | ----- |
 | Bash | [-n flag](https://www.gnu.org/software/bash/manual/bash.html#index-set) |
 | Bourne Shell | [-n flag](http://linux.die.net/man/1/sh) |
+| D | [dmd](https://dlang.org/dmd-linux.html) |
 | JavaScript | [eslint](http://eslint.org/), [jscs](http://jscs.info/), [jshint](http://jshint.com/) |
 | Python | [flake8](http://flake8.pycqa.org/en/latest/) |
 | Ruby   | [rubocop](https://github.com/bbatsov/rubocop) |

ale_linters/d/dmd.vim

@@ -0,0 +1,103 @@
+if exists('g:loaded_ale_linters_d_dmd')
+    finish
+endif
+
+let g:loaded_ale_linters_d_dmd = 1
+
+" A function for finding the dmd-wrapper script in the Vim runtime paths
+function! s:FindWrapperScript()
+    for parent in split(&runtimepath, ',')
+        let path = parent . '/' . 'dmd-wrapper'
+
+        if filereadable(path)
+            return path
+        endif
+    endfor
+endfunction
+
+function! ale_linters#d#dmd#GetDubImports(buffer)
+    if !executable('dub')
+        " If we don't have dub, then stop here.
+        return []
+    endif
+
+    " Try to find dub.json
+    let dub_path = findfile("dub.json", ",;")
+
+    if dub_path == ''
+        " Try to find package.json if that fails
+        let dub_path = findfile("package.json", ",;")
+    endif
+
+    if dub_path == ''
+        " We couldn't find the project root directory, so give up.
+        return
+    endif
+
+    let dub_dir = fnamemodify(dub_path, ':h')
+    let old_path = getcwd()
+
+    try
+        " Temporarily change to the project directory.
+        execute 'cd' . fnameescape(dub_dir)
+
+        return split(system('dub describe --import-paths'), '\n')
+    finally
+        " Change back to the old path.
+        execute 'cd' . fnameescape(old_path)
+    endtry
+endfunction
+
+function! ale_linters#d#dmd#GetCommand(buffer)
+    let wrapper_script = s:FindWrapperScript()
+
+    let command = wrapper_script . ' -o- -vcolumns -c'
+
+    for path in ale_linters#d#dmd#GetDubImports(a:buffer)
+        let command .= ' -I' . shellescape(path)
+    endfor
+
+    return command
+endfunction
+
+function! ale_linters#d#dmd#Handle(buffer, lines)
+    " Matches patterns lines like the following:
+    "
+    " /tmp/tmp.G1L5xIizvB.d(8,8): Error: module weak_reference is in file 'dstruct/weak_reference.d' which cannot be read
+    let pattern = '^[^(]\+(\([0-9]\+\),\([0-9]\+\)): \([^:]\+\): \(.\+\)'
+    let output = []
+
+    for line in a:lines
+        let l:match = matchlist(line, pattern)
+
+        if len(l:match) == 0
+            break
+        endif
+
+        let line = l:match[1] + 0
+        let column = l:match[2] + 0
+        let type = l:match[3]
+        let text = l:match[4]
+
+        " vcol is Needed to indicate that the column is a character.
+        call add(output, {
+        \   'bufnr': bufnr('%'),
+        \   'lnum': line,
+        \   'vcol': 0,
+        \   'col': column,
+        \   'text': text,
+        \   'type': type ==# 'Warning' ? 'W' : 'E',
+        \   'nr': -1,
+        \})
+    endfor
+
+    return output
+endfunction
+
+call ALEAddLinter('d', {
+\   'name': 'dmd',
+\   'output_stream': 'stderr',
+\   'executable': 'dmd',
+\   'command_callback': 'ale_linters#d#dmd#GetCommand',
+\   'callback': 'ale_linters#d#dmd#Handle',
+\})

dmd-wrapper

@@ -0,0 +1,16 @@
+#!/bin/bash -eu
+
+# This script wraps DMD so we can get something which is capable of reading
+# D code from stdin.
+
+temp_file=`mktemp`
+mv "$temp_file" "$temp_file".d
+temp_file="$temp_file".d
+
+trap "rm $temp_file" EXIT
+
+while read line; do
+    echo "$line" >> "$temp_file"
+done
+
+dmd "$@" "$temp_file"