Integrate with rustfmt

README.md

@@ -2,7 +2,7 @@
 
 ## Description
 
-This is a vim plugin that provides [Rust][r] file detection and syntax highlighting.
+This is a vim plugin that provides [Rust][r] file detection, syntax highlighting, and (optional) autoformatting.
 
 ## Installation
 
@@ -31,3 +31,12 @@ git clone --depth=1 https://github.com/rust-lang/rust.vim.git ~/.vim/bundle/rust
 
 1. Add `NeoBundle 'rust-lang/rust.vim'` to `~/.vimrc`
 2. Re-open vim or execute `:source ~/.vimrc`
+
+## Enabling autoformat
+
+This plugin can optionally format your code using [rustfmt][rfmt] every time a
+buffer is written. Simple put `let g:rustfmt_autosave = 1` in your `.vimrc`.
+
+## Help
+
+Further help can be found in the documentation with `:help rust`.

autoload/rustfmt.vim

@@ -0,0 +1,79 @@
+" Author: Stephen Sugden <stephen@stephensugden.com>
+"
+" Adapted from https://github.com/fatih/vim-go
+
+if !exists("g:rustfmt_autosave")
+  let g:rustfmt_autosave = 0
+endif
+
+if !exists("g:rustfmt_command")
+    let g:rustfmt_command = "rustfmt"
+endif
+
+if !exists("g:rustfmt_options")
+  let g:rustfmt_options = ""
+endif
+
+if !exists("g:rustfmt_fail_silently")
+  let g:rustfmt_fail_silently = 0
+endif
+
+let s:got_fmt_error = 0
+
+function! rustfmt#Format()
+  let l:curw = winsaveview()
+  let l:tmpname = expand("%:p:h") . "/." . expand("%:p:t") . ".rustfmt"
+  call writefile(getline(1, '$'), l:tmpname)
+
+  let command = g:rustfmt_command . " --write-mode=overwrite "
+
+  let out = systemlist(command . g:rustfmt_options . " " . shellescape(l:tmpname))
+
+  if v:shell_error == 0
+    " remove undo point caused via BufWritePre
+    try | silent undojoin | catch | endtry
+
+    " Replace current file with temp file, then reload buffer
+    call rename(l:tmpname, expand('%'))
+    silent edit!
+    let &syntax = &syntax
+
+    " only clear location list if it was previously filled to prevent
+    " clobbering other additions
+    if s:got_fmt_error
+      let s:got_fmt_error = 0
+      call setloclist(0, [])
+      lwindow
+    endif
+  elseif g:rustfmt_fail_silently == 0
+    " otherwise get the errors and put them in the location list
+    let errors = []
+
+    for line in out
+      " src/lib.rs:13:5: 13:10 error: expected `,`, or `}`, found `value`
+      let tokens = matchlist(line, '^\(.\{-}\):\(\d\+\):\(\d\+\):\s*\(\d\+:\d\+\s*\)\?\s*error: \(.*\)')
+      if !empty(tokens)
+        call add(errors, {"filename": @%,
+                         \"lnum":     tokens[2],
+                         \"col":      tokens[3],
+                         \"text":     tokens[5]})
+      endif
+    endfor
+
+    if empty(errors)
+      % | " Couldn't detect rustfmt error format, output errors
+    endif
+
+    if !empty(errors)
+      call setloclist(0, errors, 'r')
+      echohl Error | echomsg "rustfmt returned error" | echohl None
+    endif
+
+    let s:got_fmt_error = 1
+    lwindow
+    " We didn't use the temp file, so clean up
+    call delete(l:tmpname)
+  endif
+
+  call winrestview(l:curw)
+endfunction

doc/rust.txt

@@ -88,11 +88,37 @@ g:ftplugin_rust_source_path~
 	    let g:ftplugin_rust_source_path = $HOME.'/dev/rust'
 <
 
-                                                       *g:cargo_manifest_name*
+                                                      *g:cargo_manifest_name*
 g:cargo_manifest_name~
 	Set this option to the name of the manifest file for your projects. If
 	not specified it defaults to 'Cargo.toml' : >
-	    let g:cargo_manifest_name = 'Cargo.toml'
+	        let g:cargo_manifest_name = 'Cargo.toml'
+<
+
+                                                       *g:rustfmt_command*
+g:rustfmt_command~
+	Set this option to the name of the 'rustfmt' executable in your $PATH. If
+	not specified it defaults to 'rustfmt' : >
+	    let g:rustfmt_command = 'rustfmt'
+<
+                                                       *g:rustfmt_autosave*
+g:rustfmt_autosave~
+	Set this option to 1 to run |:RustFmt| automatically when saving a
+	buffer. If not specified it defaults to 0 : >
+	    let g:rustfmt_autosave = 0
+<
+                                                       *g:rustfmt_fail_silently*
+g:rustfmt_fail_silently~
+	Set this option to 1 to prevent 'rustfmt' from populating the
+	|location-list| with errors. If not specified it defaults to 0: >
+	    let g:rustfmt_fail_silently = 0
+<
+                                                       *g:rustfmt_options*
+g:rustfmt_options~
+	Set this option to a string of options to pass to 'rustfmt'. The
+	write-mode is already set to 'overwrite'. If not specified it 
+	defaults to '' : >
+	    let g:rustmft_options = ''
 <
 
                                                           *g:rust_playpen_url*
@@ -183,6 +209,15 @@ COMMANDS                                                       *rust-commands*
 		|g:rust_shortener_url| is the base url for the shorterner, by
 		default "https://is.gd/"
 
+:RustFmt                                                       *:RustFmt*
+		Runs |g:rustfmt_command| on the current buffer. If
+		|g:rustfmt_options| is set then those will be passed to the
+		executable.
+
+		If |g:rustfmt_fail_silently| is 0 (the default) then it
+		will populate the |location-list| with the errors from
+		|g:rustfmt_command|. If |g:rustfmt_fail_silently| is set to 1
+		then it will not populate the |location-list|.
 
 ==============================================================================
 MAPPINGS                                                       *rust-mappings*

ftplugin/rust.vim

@@ -109,6 +109,9 @@ command! -nargs=* -buffer RustEmitAsm call rust#Emit("asm", <q-args>)
 " See |:RustPlay| for docs
 command! -range=% RustPlay :call rust#Play(<count>, <line1>, <line2>, <f-args>)
 
+" See |:RustFmt| for docs
+command! -buffer RustFmt call rustfmt#Format()
+
 " Mappings {{{1
 
 " Bind ⌘R in MacVim to :RustRun

plugin/rustfmt.vim

@@ -0,0 +1,8 @@
+augroup rustfmt
+  autocmd!
+
+  " code formatting on save
+  if get(g:, "rustfmt_autosave", 0)
+    autocmd BufWritePre *.rs call rustfmt#Format()
+  endif
+augroup END