1 files changed, 116 insertions, 0 deletions
diff --git a/runtime/indent/elm.vim b/runtime/indent/elm.vim
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+" Elm indent plugin file
+" Language: Elm
+" Maintainer: Andreas Scharf <as@99n.de>
+" Original Author: Joseph Hager <ajhager@gmail.com>
+" Copyright: Joseph Hager <ajhager@gmail.com>
+" License: BSD3
+" Latest Revision: 2021-09-29
+
+" Only load this indent file when no other was loaded.
+if exists('b:did_indent')
+	finish
+endif
+let b:did_indent = 1
+
+" Local defaults
+setlocal expandtab
+setlocal indentexpr=GetElmIndent()
+setlocal indentkeys+=0=else,0=if,0=of,0=import,0=then,0=type,0\|,0},0\],0),=-},0=in
+setlocal nolisp
+setlocal nosmartindent
+
+let b:undo_indent = "setl et< inde< indk< lisp< si<"
+
+" Only define the function once.
+if exists('*GetElmIndent')
+	finish
+endif
+
+" Indent pairs
+function! s:FindPair(pstart, pmid, pend)
+	"call search(a:pend, 'bW')
+	return indent(searchpair(a:pstart, a:pmid, a:pend, 'bWn', 'synIDattr(synID(line("."), col("."), 0), "name") =~? "string\\|comment"'))
+endfunction
+
+function! GetElmIndent()
+	let l:lnum = v:lnum - 1
+
+	" Ident 0 if the first line of the file:
+	if l:lnum == 0
+		return 0
+	endif
+
+	let l:ind = indent(l:lnum)
+	let l:lline = getline(l:lnum)
+	let l:line = getline(v:lnum)
+
+	" Indent if current line begins with '}':
+	if l:line =~? '^\s*}'
+		return s:FindPair('{', '', '}')
+
+	" Indent if current line begins with 'else':
+	elseif l:line =~# '^\s*else\>'
+		if l:lline !~# '^\s*\(if\|then\)\>'
+			return s:FindPair('\<if\>', '', '\<else\>')
+		endif
+
+	" Indent if current line begins with 'then':
+	elseif l:line =~# '^\s*then\>'
+		if l:lline !~# '^\s*\(if\|else\)\>'
+			return s:FindPair('\<if\>', '', '\<then\>')
+		endif
+
+	" HACK: Indent lines in case with nearest case clause:
+	elseif l:line =~# '->' && l:line !~# ':' && l:line !~# '\\'
+		return indent(search('^\s*case', 'bWn')) + &shiftwidth
+
+	" HACK: Don't change the indentation if the last line is a comment.
+	elseif l:lline =~# '^\s*--'
+		return l:ind
+
+	" Align the end of block comments with the start
+	elseif l:line =~# '^\s*-}'
+		return indent(search('{-', 'bWn'))
+
+	" Indent double shift after let with an empty rhs
+	elseif l:lline =~# '\<let\>.*\s=$'
+		return l:ind + 4 + &shiftwidth
+
+	" Align 'in' with the parent let.
+	elseif l:line =~# '^\s*in\>'
+		return indent(search('^\s*let', 'bWn'))
+
+	" Align bindings with the parent let.
+	elseif l:lline =~# '\<let\>'
+		return l:ind + 4
+
+	" Align bindings with the parent in.
+	elseif l:lline =~# '^\s*in\>'
+		return l:ind
+
+	endif
+
+	" Add a 'shiftwidth' after lines ending with:
+	if l:lline =~# '\(|\|=\|->\|<-\|(\|\[\|{\|\<\(of\|else\|if\|then\)\)\s*$'
+		let l:ind = l:ind + &shiftwidth
+
+	" Add a 'shiftwidth' after lines starting with type ending with '=':
+	elseif l:lline =~# '^\s*type' && l:line =~# '^\s*='
+		let l:ind = l:ind + &shiftwidth
+
+	" Back to normal indent after comments:
+	elseif l:lline =~# '-}\s*$'
+		call search('-}', 'bW')
+		let l:ind = indent(searchpair('{-', '', '-}', 'bWn', 'synIDattr(synID(line("."), col("."), 0), "name") =~? "string"'))
+
+	" Ident some operators if there aren't any starting the last line.
+	elseif l:line =~# '^\s*\(!\|&\|(\|`\|+\||\|{\|[\|,\)=' && l:lline !~# '^\s*\(!\|&\|(\|`\|+\||\|{\|[\|,\)=' && l:lline !~# '^\s*$'
+		let l:ind = l:ind + &shiftwidth
+
+	elseif l:lline ==# '' && getline(l:lnum - 1) !=# ''
+		let l:ind = indent(search('^\s*\S+', 'bWn'))
+
+	endif
+
+	return l:ind
+endfunc