Change nix provider, closes #244

indent/nix.vim

@@ -0,0 +1,86 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'nix') == -1
+  
+" Vim indent file
+" Language:    Nix
+" Maintainer:  Daiderd Jordan <daiderd@gmail.com>
+" URL:         https://github.com/LnL7/vim-nix
+
+if exists("b:did_indent")
+  finish
+endif
+let b:did_indent = 1
+
+setlocal indentexpr=GetNixIndent()
+setlocal indentkeys+=0=then,0=else,0=inherit,*<Return>
+
+if exists("*GetNixIndent")
+  finish
+endif
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+let s:skip_syntax = '\%(Comment\|String\)$'
+let s:block_open  = '\%({\|[\)'
+let s:block_close = '\%(}\|]\)'
+
+function! GetNixIndent()
+  let lnum = prevnonblank(v:lnum - 1)
+  let ind  = indent(lnum)
+
+  " At the start of the file use zero indent.
+  if lnum == 0
+    return 0
+  endif
+
+  if synIDattr(synID(v:lnum, 1, 1), "name") !~ s:skip_syntax
+    let current_line = getline(v:lnum)
+    let last_line = getline(lnum)
+
+    if last_line =~ s:block_open . '\s*$'
+      let ind += &sw
+    endif
+
+    if current_line =~ '^\s*' . s:block_close
+      let ind -= &sw
+    endif
+
+    if last_line =~ '\<let\s*$'
+      let ind += &sw
+    endif
+
+    if getline(v:lnum - 1) =~ '^\<in\s*$'
+      let ind += &sw
+    endif
+
+    if current_line =~ '^\s*in\>'
+      let ind -= &sw
+    endif
+  endif
+
+  if synIDattr(synID(v:lnum, 1, 1), "name") =~ '^nixString'
+    let current_line = getline(v:lnum)
+
+    let ind = indent(v:lnum)
+    let bslnum = searchpair('''''', '', '''''', 'bnW',
+          \ 'synIDattr(synID(line("."), col("."), 0), "name") =~? "InterpolationSpecial$"')
+
+    if ind <= indent(bslnum)
+      let ind = indent(bslnum) + &sw
+    endif
+
+    if current_line =~ '^\s*''''[^''\$]'
+      let ind = indent(bslnum)
+    endif
+    if current_line =~ '^\s*''''$'
+      let ind = indent(bslnum)
+    endif
+  endif
+
+  return ind
+endfunction
+
+let &cpo = s:cpo_save
+unlet s:cpo_save
+
+endif