neovim/runtime/indent/rust.vim

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" Vim indent file
" Language: Rust
" Author: Chris Morgan <me@chrismorgan.info>
" Last Change: 2023-09-11
" 2024 Jul 04 by Vim Project: use shiftwidth() instead of hard-coding shifted values (#15138)
" For bugs, patches and license go to https://github.com/rust-lang/rust.vim
" Note: upstream seems umaintained: https://github.com/rust-lang/rust.vim/issues/502
" 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,(s,Ws,J1,j1,m1
setlocal cinkeys=0{,0},!^F,o,O,0[,0],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,macro
" 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],0(,0)
setlocal indentexpr=GetRustIndent(v:lnum)
let b:undo_indent = "setlocal cindent< cinoptions< cinkeys< cinwords< lisp< autoindent< indentkeys< indentexpr<"
" Only define the function once.
if exists("*GetRustIndent")
finish
endif
" vint: -ProhibitAbbreviationOption
let s:save_cpo = &cpo
set cpo&vim
" vint: +ProhibitAbbreviationOption
" 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
if exists('*shiftwidth')
function! s:shiftwidth()
return shiftwidth()
endfunc
else
function! s:shiftwidth()
return &shiftwidth
endfunc
endif
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
" A standalone '{', '}', or 'where'
let l:standalone_open = line =~# '\V\^\s\*{\s\*\$'
let l:standalone_close = line =~# '\V\^\s\*}\s\*\$'
let l:standalone_where = line =~# '\V\^\s\*where\s\*\$'
if l:standalone_open || l:standalone_close || l:standalone_where
" ToDo: we can search for more items than 'fn' and 'if'.
let [l:found_line, l:col, l:submatch] =
\ searchpos('\<\(fn\)\|\(if\)\>', 'bnWp')
if l:found_line !=# 0
" Now we count the number of '{' and '}' in between the match
" locations and the current line (there is probably a better
" way to compute this).
let l:i = l:found_line
let l:search_line = strpart(getline(l:i), l:col - 1)
let l:opens = 0
let l:closes = 0
while l:i < a:lnum
let l:search_line2 = substitute(l:search_line, '\V{', '', 'g')
let l:opens += strlen(l:search_line) - strlen(l:search_line2)
let l:search_line3 = substitute(l:search_line2, '\V}', '', 'g')
let l:closes += strlen(l:search_line2) - strlen(l:search_line3)
let l:i += 1
let l:search_line = getline(l:i)
endwhile
if l:standalone_open || l:standalone_where
if l:opens ==# l:closes
return indent(l:found_line)
endif
else
" Expect to find just one more close than an open
if l:opens ==# l:closes + 1
return indent(l:found_line)
endif
endif
endif
endif
" A standalone 'where' adds a shift.
let l:standalone_prevline_where = prevline =~# '\V\^\s\*where\s\*\$'
if l:standalone_prevline_where
return indent(prevlinenum) + shiftwidth()
endif
" Handle where clauses nicely: subsequent values should line up nicely.
if prevline[len(prevline) - 1] ==# ","
\ && prevline =~# '^\s*where\s'
return indent(prevlinenum) + 6
endif
let l:last_prevline_character = prevline[len(prevline) - 1]
" A line that ends with '.<expr>;' is probably an end of a long list
" of method operations.
if prevline =~# '\V\^\s\*.' && l:last_prevline_character ==# ';'
call cursor(a:lnum - 1, 1)
let l:scope_start = searchpair('{\|(', '', '}\|)', 'nbW',
\ 's:is_string_comment(line("."), col("."))')
if l:scope_start != 0 && l:scope_start < a:lnum
return indent(l:scope_start) + shiftwidth()
endif
endif
if l:last_prevline_character ==# ","
\ && s:get_line_trimmed(a:lnum) !~# '^\s*[\[\]{})]'
\ && prevline !~# '^\s*fn\s'
\ && prevline !~# '([^()]\+,$'
\ && s:get_line_trimmed(a:lnum) !~# '^\s*\S\+\s*=>'
" 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) {
"
" Another case is when the current line is a new match arm.
"
" There are probably other cases where we don't want to do this as
" well. Add them as needed.
return indent(prevlinenum)
endif
if !has("patch-7.4.355")
" cindent before 7.4.355 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
endif
" Fall back on cindent, which does it mostly right
return cindent(a:lnum)
endfunction
" vint: -ProhibitAbbreviationOption
let &cpo = s:save_cpo
unlet s:save_cpo
" vint: +ProhibitAbbreviationOption
" vim: set et sw=4 sts=4 ts=8: