" Vim indent file
" Language: Rust
" Author: Chris Morgan <me@chrismorgan.info>
" Last Change: 2013 Oct 29
" Only load this indent file when no other was loaded.
if exists("b:did_indent")
finish
endif
let b:did_indent = 1
setlocal cindent
setlocal cinoptions=L0,(0,Ws,JN,j1
setlocal cinkeys=0{,0},!^F,o,O,0[,0]
" Don't think cinwords will actually do anything at all... never mind
setlocal cinwords=for,if,else,while,loop,impl,mod,unsafe,trait,struct,enum,fn,extern
" Some preliminary settings
setlocal nolisp " Make sure lisp indenting doesn't supersede us
setlocal autoindent " indentexpr isn't much help otherwise
" Also do indentkeys, otherwise # gets shoved to column 0 :-/
setlocal indentkeys=0{,0},!^F,o,O,0[,0]
setlocal indentexpr=GetRustIndent(v:lnum)
" Only define the function once.
if exists("*GetRustIndent")
finish
endif
" Come here when loading the script the first time.
function! s:get_line_trimmed(lnum)
" Get the line and remove a trailing comment.
" Use syntax highlighting attributes when possible.
" NOTE: this is not accurate; /* */ or a line continuation could trick it
let line = getline(a:lnum)
let line_len = strlen(line)
if has('syntax_items')
" If the last character in the line is a comment, do a binary search for
" the start of the comment. synID() is slow, a linear search would take
" too long on a long line.
if synIDattr(synID(a:lnum, line_len, 1), "name") =~ 'Comment\|Todo'
let min = 1
let max = line_len
while min < max
let col = (min + max) / 2
if synIDattr(synID(a:lnum, col, 1), "name") =~ 'Comment\|Todo'
let max = col
else
let min = col + 1
endif
endwhile
let line = strpart(line, 0, min - 1)
endif
return substitute(line, "\s*$", "", "")
else
" Sorry, this is not complete, nor fully correct (e.g. string "//").
" Such is life.
return substitute(line, "\s*//.*$", "", "")
endif
endfunction
function! s:is_string_comment(lnum, col)
if has('syntax_items')
for id in synstack(a:lnum, a:col)
let synname = synIDattr(id, "name")
if synname == "rustString" || synname =~ "^rustComment"
return 1
endif
endfor
else
" without syntax, let's not even try
return 0
endif
endfunction
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')
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 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
" Fun fact: " /*\n*\n*/" takes two calls to get right!
return cindent(a:lnum)
endif
endif
" cindent gets second and subsequent match patterns/struct members wrong,
" as it treats the comma as indicating an unfinished statement::
"
" match a {
" b => c,
" d => e,
" f => g,
" };
" Search backwards for the previous non-empty line.
let prevlinenum = prevnonblank(a:lnum - 1)
let prevline = s:get_line_trimmed(prevlinenum)
while prevlinenum > 1 && prevline !~ '[^[:blank:]]'
let prevlinenum = prevnonblank(prevlinenum - 1)
let prevline = s:get_line_trimmed(prevlinenum)
endwhile
if prevline[len(prevline) - 1] == ","
\ && s:get_line_trimmed(a:lnum) !~ '^\s*[\[\]{}]'
\ && prevline !~ '^\s*fn\s'
\ && prevline !~ '([^()]\+,$'
" Oh ho! The previous line ended in a comma! I bet cindent will try to
" take this too far... For now, let's normally use the previous line's
" indent.
" One case where this doesn't work out is where *this* line contains
" square or curly brackets; then we normally *do* want to be indenting
" further.
"
" Another case where we don't want to is one like a function
" definition with arguments spread over multiple lines:
"
" fn foo(baz: Baz,
" baz: Baz) // <-- cindent gets this right by itself
"
" Another case is similar to the previous, except calling a function
" instead of defining it, or any conditional expression that leaves
" an open paren:
"
" foo(baz,
" baz);
"
" if baz && (foo ||
" bar) {
"
" There are probably other cases where we don't want to do this as
" well. Add them as needed.
return GetRustIndent(a:lnum - 1)
endif
" cindent doesn't do the module scope well at all; e.g.::
"
" static FOO : &'static [bool] = [
" true,
" false,
" false,
" true,
" ];
"
" uh oh, next statement is indented further!
" Note that this does *not* apply the line continuation pattern properly;
" that's too hard to do correctly for my liking at present, so I'll just
" start with these two main cases (square brackets and not returning to
" column zero)
call cursor(a:lnum, 1)
if searchpair('{\|(', '', '}\|)', 'nbW',
\ 's:is_string_comment(line("."), col("."))') == 0
if searchpair('\[', '', '\]', 'nbW',
\ 's:is_string_comment(line("."), col("."))') == 0
" Global scope, should be zero
return 0
else
" At the module scope, inside square brackets only
"if getline(a:lnum)[0] == ']' || search('\[', '', '\]', 'nW') == a:lnum
if line =~ "^\\s*]"
" It's the closing line, dedent it
return 0
else
return &shiftwidth
endif
endif
endif
" Fall back on cindent, which does it mostly right
return cindent(a:lnum)
endfunction
