Fix comment indenting properly for Vim files.

Indentation now works correctly on subsequent lines of a multi-line
comment, whether there are leaders (` * `) or not. (Formerly it was
incorrectly doing a two-space indent if there was no leader.)

By default, this no longer puts a ` * ` leader on `/*!` comments, as
that appears to be the current convention in the Rust source code, but
that can easily be re-enabled if desired:

    let g:rust_bang_comment_leader = 1

Author: chris-morgan

src/etc/vim/ftplugin/rust.vim

@@ -1,14 +1,25 @@
 " Vim syntax file
 " Language:     Rust
 " Maintainer:   Chris Morgan <[email protected]>
-" Last Change:  2013 Jul 6
+" Last Change:  2013 Jul 10
 
 if exists("b:did_ftplugin")
 	finish
 endif
 let b:did_ftplugin = 1
 
-setlocal comments=s1:/*,mb:*,ex:*/,:///,://!,://
+" The rust source code at present seems to typically omit a leader on /*!
+" comments, so we'll use that as our default, but make it easy to switch.
+" This does not affect indentation at all (I tested it with and without
+" leader), merely whether a leader is inserted by default or not.
+if exists("g:rust_bang_comment_leader") && g:rust_bang_comment_leader == 1
+	" Why is the `,s0:/*,mb:\ ,ex:*/` there, you ask? I don't understand why,
+	" but without it, */ gets indented one space even if there were no
+	" leaders. I'm fairly sure that's a Vim bug.
+	setlocal comments=s1:/*,mb:*,ex:*/,s0:/*,mb:\ ,ex:*/,:///,://!,://
+else
+	setlocal comments=s0:/*!,m:\ ,ex:*/,s1:/*,mb:*,ex:*/,:///,://!,://
+endif
 setlocal commentstring=//%s
 setlocal formatoptions-=t formatoptions+=croqnlj
 

src/etc/vim/indent/rust.vim

@@ -66,12 +66,23 @@ function GetRustIndent(lnum)
 	" Starting assumption: cindent (called at the end) will do it right
 	" normally. We just want to fix up a few cases.
 
+	let line = getline(a:lnum)
+
 	if has('syntax_items')
-		if synIDattr(synID(a:lnum, 1, 1), "name") == "rustString"
+		let synname = synIDattr(synID(a:lnum, 1, 1), "name")
+		if synname == "rustString"
 			" If the start of the line is in a string, don't change the indent
 			return -1
-		elseif synIDattr(synID(a:lnum, 1, 1), "name") =~ "\\(Comment\\|Todo\\)"
-					\ && getline(a:lnum) !~ "^\\s*/\\*"
+		elseif synname =~ "\\(Comment\\|Todo\\)"
+					\ && line !~ "^\\s*/\\*"  " not /* opening line
+			if synname =~ "CommentML" " multi-line
+				if line !~ "^\\s*\\*" && getline(a:lnum - 1) =~ "^\\s*/\\*"
+					" This is (hopefully) the line after a /*, and it has no
+					" leader, so the correct indentation is that of the
+					" previous line.
+					return GetRustIndent(a:lnum - 1)
+				endif
+			endif
 			" If it's in a comment, let cindent take care of it now. This is
 			" for cases like "/*" where the next line should start " * ", not
 			" "* " as the code below would otherwise cause for module scope
@@ -114,7 +125,6 @@ function GetRustIndent(lnum)
 	" start with these two main cases (square brackets and not returning to
 	" column zero)
 
-	let line = getline(a:lnum)
 	call cursor(a:lnum, 1)
 	if searchpair('{\|(', '', '}\|)', 'nbW') == 0
 		if searchpair('\[', '', '\]', 'nbW') == 0

src/etc/vim/syntax/rust.vim

@@ -117,9 +117,9 @@ syn match     rustFloat       display "\<[0-9][0-9_]*\.[0-9_]\+\%([eE][+-]\=[0-9
 syn match     rustLifetime    display "\'\%([^[:cntrl:][:space:][:punct:][:digit:]]\|_\)\%([^[:cntrl:][:punct:][:space:]]\|_\)*"
 syn match   rustCharacter   "'\([^'\\]\|\\\(['nrt\\\"]\|x\x\{2}\|u\x\{4}\|U\x\{8}\)\)'"
 
-syn region    rustComment     start="/\*" end="\*/" contains=rustTodo
+syn region    rustCommentML   start="/\*" end="\*/" contains=rustTodo
 syn region    rustComment     start="//" skip="\\$" end="$" contains=rustTodo keepend
-syn region    rustCommentDoc  start="/\*\%(!\|\*/\@!\)" end="\*/" contains=rustTodo
+syn region    rustCommentMLDoc start="/\*\%(!\|\*/\@!\)" end="\*/" contains=rustTodo
 syn region    rustCommentDoc  start="//[/!]" skip="\\$" end="$" contains=rustTodo keepend
 
 syn keyword rustTodo contained TODO FIXME XXX NB NOTE
@@ -151,7 +151,9 @@ hi def link rustModPath       Include
 hi def link rustModPathSep    Delimiter
 hi def link rustFuncName      Function
 hi def link rustFuncCall      Function
+hi def link rustCommentMLDoc  rustCommentDoc
 hi def link rustCommentDoc    SpecialComment
+hi def link rustCommentML     rustComment
 hi def link rustComment       Comment
 hi def link rustAssert        PreCondit
 hi def link rustFail          PreCondit