Initial version

Mostly copied from idris-vim

indent/idris2.vim

@@ -0,0 +1,144 @@
+" indentation for idris (idris-lang.org)
+"
+" Based on haskell indentation by motemen <motemen@gmail.com>
+"
+" author: raichoo (raichoo@googlemail.com)
+"
+" Modify g:idris_indent_if and g:idris_indent_case to
+" change indentation for `if'(default 3) and `case'(default 5).
+" Example (in .vimrc):
+" > let g:idris_indent_if = 2
+
+if exists('b:did_indent')
+  finish
+endif
+
+let b:did_indent = 1
+
+if !exists('g:idris_indent_if')
+  " if bool
+  " >>>then ...
+  " >>>else ...
+  let g:idris_indent_if = 3
+endif
+
+if !exists('g:idris_indent_case')
+  " case xs of
+  " >>>>>[]      => ...
+  " >>>>>(y::ys) => ...
+  let g:idris_indent_case = 5
+endif
+
+if !exists('g:idris_indent_let')
+  " let x : Nat = O in
+  " >>>>x
+  let g:idris_indent_let = 4
+endif
+
+if !exists('g:idris_indent_rewrite')
+  " rewrite prf in expr
+  " >>>>>>>>x
+  let g:idris_indent_rewrite = 8
+endif
+
+if !exists('g:idris_indent_where')
+  " where f : Nat -> Nat
+  " >>>>>>f x = x
+  let g:idris_indent_where = 6
+endif
+
+if !exists('g:idris_indent_do')
+  " do x <- a
+  " >>>y <- b
+  let g:idris_indent_do = 3
+endif
+
+setlocal indentexpr=GetIdrisIndent()
+setlocal indentkeys=!^F,o,O,}
+
+function! GetIdrisIndent()
+  let prevline = getline(v:lnum - 1)
+
+  if prevline =~ '\s\+(\s*.\+\s\+:\s\+.\+\s*)\s\+->\s*$'
+    return match(prevline, '(')
+  elseif prevline =~ '\s\+{\s*.\+\s\+:\s\+.\+\s*}\s\+->\s*$'
+    return match(prevline, '{')
+  endif
+
+  if prevline =~ '[!#$%&*+./<>?@\\^|~-]\s*$'
+    let s = match(prevline, '[:=]')
+    if s > 0
+      return s + 2
+    else
+      return match(prevline, '\S')
+    endif
+  endif
+
+  if prevline =~ '[{([][^})\]]\+$'
+    return match(prevline, '[{([]')
+  endif
+
+  if prevline =~ '\<let\>\s\+.\+\<in\>\s*$'
+    return match(prevline, '\<let\>') + g:idris_indent_let
+  endif
+
+  if prevline =~ '\<rewrite\>\s\+.\+\<in\>\s*$'
+    return match(prevline, '\<rewrite\>') + g:idris_indent_rewrite
+  endif
+
+  if prevline !~ '\<else\>'
+    let s = match(prevline, '\<if\>.*\&.*\zs\<then\>')
+    if s > 0
+      return s
+    endif
+
+    let s = match(prevline, '\<if\>')
+    if s > 0
+      return s + g:idris_indent_if
+    endif
+  endif
+
+  if prevline =~ '\(\<where\>\|\<do\>\|=\|[{([]\)\s*$'
+    return match(prevline, '\S') + &shiftwidth
+  endif
+
+  if prevline =~ '\<where\>\s\+\S\+.*$'
+    return match(prevline, '\<where\>') + g:idris_indent_where
+  endif
+
+  if prevline =~ '\<do\>\s\+\S\+.*$'
+    return match(prevline, '\<do\>') + g:idris_indent_do
+  endif
+
+  if prevline =~ '^\s*\<\(co\)\?data\>\s\+[^=]\+\s\+=\s\+\S\+.*$'
+    return match(prevline, '=')
+  endif
+
+  if prevline =~ '\<with\>\s\+([^)]*)\s*$'
+    return match(prevline, '\S') + &shiftwidth
+  endif
+
+  if prevline =~ '\<case\>\s\+.\+\<of\>\s*$'
+    return match(prevline, '\<case\>') + g:idris_indent_case
+  endif
+
+  if prevline =~ '^\s*\(\<namespace\>\|\<\(co\)\?data\>\)\s\+\S\+\s*$'
+    return match(prevline, '\(\<namespace\>\|\<\(co\)\?data\>\)') + &shiftwidth
+  endif
+
+  if prevline =~ '^\s*\(\<using\>\|\<parameters\>\)\s*([^(]*)\s*$'
+    return match(prevline, '\(\<using\>\|\<parameters\>\)') + &shiftwidth
+  endif
+
+  if prevline =~ '^\s*\<mutual\>\s*$'
+    return match(prevline, '\<mutual\>') + &shiftwidth
+  endif
+
+  let line = getline(v:lnum)
+
+  if (line =~ '^\s*}\s*' && prevline !~ '^\s*;')
+    return match(prevline, '\S') - &shiftwidth
+  endif
+
+  return match(prevline, '\S')
+endfunction