Enable DartFmt Options with g:dartfmt_options (#108)

- Use f-args instead of q-args and use varags for the funciton so all
  arguments are lists.
- Add a missing `shellescape` in case there are characters in the
  filename that need to be escaped.
- Extend the default args with the dartfmt_options args, and the
  manually supplied arguments to the command.

README.md

@@ -79,6 +79,9 @@ Enable Dart style guide syntax (like 2-space indentation) with
 
 Enable DartFmt execution on buffer save with `let g:dart_format_on_save = 1`
 
+Configure DartFmt options with `let g:dartfmt_options`
+(discover formatter options with `dartfmt -h`)
+
 ## FAQ
 
 ### Why doesn't the plugin indent identically to `dartfmt`?

autoload/dart.vim

@@ -25,12 +25,16 @@ function! s:clearQfList(reason) abort
   endif
 endfunction
 
-function! dart#fmt(q_args) abort
-  let cmd = s:FindDartFmt()
-  if type(cmd) != type('') | return | endif
+function! dart#fmt(...) abort
+  let l:dartfmt = s:FindDartFmt()
+  if type(l:dartfmt) != type('') | return | endif
   let buffer_content = getline(1, '$')
-  let args = '--stdin-name '.expand('%').' '.a:q_args
-  let lines = systemlist(printf('%s %s', cmd, args), join(buffer_content, "\n"))
+  let l:cmd = [l:dartfmt, '--stdin-name', shellescape(expand('%'))]
+  if exists('g:dartfmt_options')
+    call extend(l:cmd, g:dartfmt_options)
+  endif
+  call extend(l:cmd, a:000)
+  let lines = systemlist(join(l:cmd), join(buffer_content, "\n"))
   " TODO(https://github.com/dart-lang/sdk/issues/38507) - Remove once the
   " tool no longer emits this line on SDK upgrades.
   if lines[-1] ==# 'Isolate creation failed'

doc/dart.txt

@@ -51,6 +51,11 @@ Set to any value (set to `2` by convention) to set tab and width behavior to
 match the Dart style guide - spaces only with an indent of 2. Also sets
 `formatoptions += t` to auto wrap text.
 
+Configure DartFmt options with `let g:dartfmt_options`, for example, enable
+auto syntax fixes with `let g:dartfmt_options = ['--fix']`
+(discover formatter options with `dartfmt -h`)
+
+
 SYNTAX HIGHLIGHTING                              *dart-syntax*
 
 This plugin uses narrow highlight groups to allow selectively disabling the

plugin/dart.vim

@@ -10,14 +10,14 @@ set cpo&vim
 function! s:FormatOnSave()
   " Dart code formatting on save
   if get(g:, 'dart_format_on_save', 0)
-    call dart#fmt('')
+    call dart#fmt()
   endif
 endfunction
 
 augroup dart-vim-plugin
   autocmd!
   autocmd BufWritePre *.dart call s:FormatOnSave()
-  autocmd FileType dart command! -buffer -nargs=? DartFmt       call dart#fmt(<q-args>)
+  autocmd FileType dart command! -buffer -nargs=? DartFmt       call dart#fmt(<f-args>)
   autocmd FileType dart command! -buffer DartToggleFormatOnSave call dart#ToggleFormatOnSave()
   autocmd FileType dart command! -buffer -nargs=? Dart2Js       call dart#tojs(<q-args>)
   autocmd FileType dart command! -buffer -nargs=? DartAnalyzer  call dart#analyzer(<q-args>)