Update

1 files changed, 171 insertions, 32 deletions

diff --git a/indent/purescript.vim b/indent/purescript.vim
index c456c608..c22da095 100644
--- a/indent/purescript.vim
+++ b/indent/purescript.vim
@@ -37,9 +37,16 @@ if !exists('g:purescript_indent_let')
   let g:purescript_indent_let = 4
 endif
 
+if !exists('g:purescript_indent_in')
+  " let x = 0
+  " >in
+  let g:purescript_indent_in = 1
+endif
+
 if !exists('g:purescript_indent_where')
-  " where f :: Int -> Int
-  " >>>>>>f x = x
+  " where
+  " >>f :: Int -> Int
+  " >>f x = x
   let g:purescript_indent_where = 6
 endif
 
@@ -49,16 +56,29 @@ if !exists('g:purescript_indent_do')
   let g:purescript_indent_do = 3
 endif
 
+if !exists('g:purescript_indent_dot')
+  " f
+  "   :: forall a
+  "   >. String
+  "   -> String
+  let g:purescript_indent_dot = 1
+endif
+
 setlocal indentexpr=GetPurescriptIndent()
-setlocal indentkeys=!^F,o,O,},=where,=in
+setlocal indentkeys=!^F,o,O,},=where,=in,=::,=->,=→,==>,=⇒
+
+function! s:GetSynStack(lnum, col)
+  return map(synstack(a:lnum, a:col), { key, val -> synIDattr(val, "name") })
+endfunction
 
 function! GetPurescriptIndent()
+  let ppline = getline(v:lnum - 2)
   let prevline = getline(v:lnum - 1)
   let line = getline(v:lnum)
 
   if line =~ '^\s*\<where\>'
-    let s = match(prevline, '\S')
-    return s + 2
+    let s = indent(v:lnum - 1)
+    return max([s, &l:shiftwidth])
   endif
 
   if line =~ '^\s*\<in\>'
@@ -67,72 +87,191 @@ function! GetPurescriptIndent()
 
     while s <= 0 && n > 0
       let n = n - 1
-      let s = match(getline(n),'\<let\>')
+      let s = match(getline(n), '\<let\>')
+      if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') != -1
+	let s = -1
+      endif
     endwhile
 
-    return s + 1
+    return s + g:purescript_indent_in
+  endif
+
+  let s = match(prevline, '^\s*\zs\(--\|import\)')
+  if s >= 0
+    " comments
+    " imports
+    return s
+  endif
+
+  if prevline =~ '^\S.*::' && line !~ '^\s*\(\.\|->\|→\|=>\|⇒\)' && !~ '^instance'
+    " f :: String
+    "	-> String
+    return 0
+  endif
+
+  let s = match(prevline, '[[:alnum:][:blank:]]\@<=|[[:alnum:][:blank:]$]')
+  if s >= 0 && prevline !~ '^class\>' && index(s:GetSynStack(v:lnum - 1, s), "purescriptFunctionDecl") == -1
+    " ident pattern guards but not if we are in a type declaration
+    " what we detect using syntax groups
+    if prevline =~ '|\s*otherwise\>'
+      return indent(search('^\s*\k', 'bnW'))
+      " somehow this pattern does not work :/
+      " return indent(search('^\(\s*|\)\@!', 'bnW'))
+    else
+      return s
+    endif
+  endif
+
+  let s = match(line, '\%(\\.\{-}\)\@<=->')
+  if s >= 0
+    " inline lambda
+    return indent(v:lnum)
+  endif
+
+  " indent rules for -> (lambdas and case expressions)
+  let s = match(line, '->')
+  let p = match(prevline, '\\')
+  " protect that we are not in a type signature
+  " and not in a case expression
+  if s >= 0 && index(s:GetSynStack(s == 0 ? v:lnum - 1 : v:lnum, max([1, s])), "purescriptFunctionDecl") == -1
+    \ && p >= 0 &&  index(s:GetSynStack(v:lnum - 1, p), "purescriptString") == -1
+    return p
+  endif
+
+  if prevline =~ '^\S'
+    " start typing signature, function body, data & newtype on next line
+    return &l:shiftwidth
   endif
 
-  if prevline =~ '[!#$%&*+./<>?@\\^|~-]\s*$'
+  if ppline =~ '^\S' && prevline =~ '^\s*$'
+    return 0
+  endif
+
+  if line =~ '^\s*\%(::\|∷\)'
+    return match(prevline, '\S') + &l:shiftwidth
+  endif
+
+  if prevline =~ '^\s*\(::\|∷\)\s*forall'
+    return match(prevline, '\S') + g:purescript_indent_dot
+  endif
+
+  let s = match(prevline, '^\s*\zs\%(::\|∷\|=>\|⇒\|->\|→\)')
+  let r = match(prevline, '^\s*\zs\.')
+  if s >= 0 || r >= 0
+    if s >= 0
+      if line !~ '^\s*\%(::\|∷\|=>\|⇒\|->\|→\)' && line !~ '^\s*$'
+	return s - 2
+      else
+	return s
+      endif
+    elseif r >= 0
+      if line !~ '^\s\%(::\|∷\|=>\|⇒\|->\|→\)'
+	return r - g:purescript_indent_dot
+      else
+	return r
+      endif
+    endif
+  endif
+
+  if prevline =~ '[!#$%&*+./<>?@\\^~-]\s*$'
     let s = match(prevline, '=')
     if s > 0
-      return s + 2
+      return s + &l:shiftwidth
     endif
 
-    let s = match(prevline, ':')
+    let s = match(prevline, '\<:\>')
     if s > 0
-      return s + 3
+      return s + &l:shiftwidth
     else
-      return match(prevline, '\S')
+      return match(prevline, '\S') + &l:shiftwidth
     endif
   endif
 
   if prevline =~ '[{([][^})\]]\+$'
+    echom "return 1"
     return match(prevline, '[{([]')
   endif
 
-  if prevline =~ '\<let\>\s\+.\+\(\<in\>\)\?\s*$'
+  let s = match(prevline, '\<let\>\s\+\zs\S')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return s
+  endif
+
+  let s = match(prevline, '\<let\>\s*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return s + g:purescript_indent_let
+  endif
+
+  let s = match(prevline, '\<let\>\s\+.\+\(\<in\>\)\?\s*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
     return match(prevline, '\<let\>') + g:purescript_indent_let
   endif
 
-  if prevline !~ '\<else\>'
-    let s = match(prevline, '\<if\>.*\&.*\zs\<then\>')
-    if s > 0
-      return s
+  let s = searchpairpos('\%(--.\{-}\)\@<!\<if\>', '\<then\>', '\<else\>.*\zs$', 'bnrc')[0]
+  if s > 0
+    " this rule ensures that using `=` in visual mode will correctly indent
+    " `if then else`, but it does not handle lines after `then` and `else`
+    if line =~ '\<\%(then\|else\)\>'
+      return match(getline(s), '\<if\>') + &l:shiftwidth
     endif
+  endif
 
-    let s = match(prevline, '\<if\>')
-    if s > 0
-      return s + g:purescript_indent_if
-    endif
+  let p = match(prevline, '\<if\>\%(.\{-}\<then\>.\{-}\<else\>\)\@!')
+  if p > 0
+    return p + &l:shiftwidth
+  endif
+
+  let s = match(prevline, '=\s*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return match(prevline, '\S') + &l:shiftwidth
+  endif
+
+  let s = match(prevline, '[{([]\s*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return match(prevline, '\S') + (line !~ '^\s*[})]]' ? 0 : &l:shiftwidth)
+  endif
+
+  if prevline =~ '^class'
+    return &l:shiftwidth
+  endif
+
+  let s = match(prevline, '\<where\>\s*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return match(prevline, '\S') + g:purescript_indent_where
   endif
 
-  if prevline =~ '\(\<where\>\|\<do\>\|=\|[{([]\)\s*$'
-    return match(prevline, '\S') + &shiftwidth
+  let s = match(prevline, '\<where\>\s\+\zs\S\+.*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return s
   endif
 
-  if prevline =~ '\<where\>\s\+\S\+.*$'
-    return match(prevline, '\<where\>') + g:purescript_indent_where
+  let s = match(prevline, '\<do\>\s*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return match(prevline, '\S') + g:purescript_indent_do
   endif
 
-  if prevline =~ '\<do\>\s\+\S\+.*$'
-    return match(prevline, '\<do\>') + g:purescript_indent_do
+  let s = match(prevline, '\<do\>\s\+\zs\S\+.*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return s
   endif
 
-  if prevline =~ '^\s*\<data\>\s\+[^=]\+\s\+=\s\+\S\+.*$'
+  let s = match(prevline, '^\s*\<data\>\s\+[^=]\+\s\+=\s\+\S\+.*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
     return match(prevline, '=')
   endif
 
-  if prevline =~ '\<case\>\s\+.\+\<of\>\s*$'
+  let s = match(prevline, '\<case\>\s\+.\+\<of\>\s*$')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
     return match(prevline, '\<case\>') + g:purescript_indent_case
   endif
 
   if prevline =~ '^\s*\<\data\>\s\+\S\+\s*$'
-    return match(prevline, '\<data\>') + &shiftwidth
+    return match(prevline, '\<data\>') + &l:shiftwidth
   endif
 
-  if (line =~ '^\s*}\s*' && prevline !~ '^\s*;')
-    return match(prevline, '\S') - &shiftwidth
+  let s = match(prevline, '^\s*[}\]]')
+  if s >= 0 && index(s:GetSynStack(v:lnum - 1, s), 'purescriptString') == -1
+    return match(prevline, '\S') - &l:shiftwidth
   endif
 
   return match(prevline, '\S')