1 files changed, 44 insertions, 0 deletions
diff --git a/runtime/indent/yacc.vim b/runtime/indent/yacc.vim
new file mode 100644
index 0000000..253ccc5
--- /dev/null
+++ b/runtime/indent/yacc.vim
@@ -0,0 +1,44 @@
+" Vim indent file
+" Language:		YACC input file
+" Maintainer:		Doug Kearns <dougkearns@gmail.com>
+" Previous Maintainer:	Nikolai Weibull <now@bitwi.se>
+" Last Change:		2022 April 25
+
+" Only load this indent file when no other was loaded.
+if exists("b:did_indent")
+  finish
+endif
+
+let b:did_indent = 1
+
+setlocal indentexpr=GetYaccIndent()
+setlocal indentkeys=!^F,o,O
+setlocal nosmartindent
+
+let b:undo_indent = "setl inde< indk< si<"
+
+" Only define the function once.
+if exists("*GetYaccIndent")
+  finish
+endif
+
+function GetYaccIndent()
+  if v:lnum == 1
+    return 0
+  endif
+
+  let ind = indent(v:lnum - 1)
+  let line = getline(v:lnum - 1)
+
+  if line == ''
+    let ind = 0
+  elseif line =~ '^\w\+\s*:'
+    let ind = ind + matchend(line, '^\w\+\s*')
+  elseif line =~ '^\s*;'
+    let ind = 0
+  else
+    let ind = indent(v:lnum)
+  endif
+
+  return ind
+endfunction