1 files changed, 43 insertions, 0 deletions
diff --git a/src/nvim/indent.c b/src/nvim/indent.c
index 3f5a8afbc1..3f08aa7043 100644
--- a/src/nvim/indent.c
+++ b/src/nvim/indent.c
@@ -15,6 +15,7 @@
 #include "nvim/eval.h"
 #include "nvim/extmark.h"
 #include "nvim/indent.h"
+#include "nvim/indent_c.h"
 #include "nvim/mark.h"
 #include "nvim/memline.h"
 #include "nvim/memory.h"
@@ -1144,3 +1145,45 @@ static int lisp_match(char_u *p)
   }
   return false;
 }
+
+/// Re-indent the current line, based on the current contents of it and the
+/// surrounding lines. Fixing the cursor position seems really easy -- I'm very
+/// confused what all the part that handles Control-T is doing that I'm not.
+/// "get_the_indent" should be get_c_indent, get_expr_indent or get_lisp_indent.
+void fixthisline(IndentGetter get_the_indent)
+{
+  int amount = get_the_indent();
+
+  if (amount >= 0) {
+    change_indent(INDENT_SET, amount, false, 0, true);
+    if (linewhite(curwin->w_cursor.lnum)) {
+      did_ai = true;  // delete the indent if the line stays empty
+    }
+  }
+}
+
+/// Return true if 'indentexpr' should be used for Lisp indenting.
+/// Caller may want to check 'autoindent'.
+bool use_indentexpr_for_lisp(void)
+{
+  return curbuf->b_p_lisp
+         && *curbuf->b_p_inde != NUL
+         && strcmp(curbuf->b_p_lop, "expr:1") == 0;
+}
+
+/// Fix indent for 'lisp' and 'cindent'.
+void fix_indent(void)
+{
+  if (p_paste) {
+    return;  // no auto-indenting when 'paste' is set
+  }
+  if (curbuf->b_p_lisp && curbuf->b_p_ai) {
+    if (use_indentexpr_for_lisp()) {
+      do_c_expr_indent();
+    } else {
+      fixthisline(get_lisp_indent);
+    }
+  } else if (cindent_on()) {
+    do_c_expr_indent();
+  }
+}