From 7301f3964c518858ba6e3ffc2404baee1734639b Mon Sep 17 00:00:00 2001
From: "Kartik K. Agaram" <vc@akkartik.com>
Date: Fri, 3 Jun 2022 07:48:41 -0700
Subject: up arrow to search previous

---
 text.lua | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'text.lua')

diff --git a/text.lua b/text.lua
index 5c468b2..3c3bb9d 100644
--- a/text.lua
+++ b/text.lua
@@ -163,6 +163,56 @@ function Text.search_next()
   end
 end
 
+function Text.search_previous()
+  -- search current line
+  local pos = rfind(Lines[Cursor1.line].data, Search_term, Cursor1.pos)
+  if pos then
+    Cursor1.pos = pos
+  end
+  if pos == nil then
+    for i=Cursor1.line-1,1,-1 do
+      pos = rfind(Lines[i].data, Search_term)
+      if pos then
+        Cursor1.line = i
+        Cursor1.pos = pos
+        break
+      end
+    end
+  end
+  if pos == nil then
+    -- wrap around
+    for i=#Lines,Cursor1.line+1,-1 do
+      pos = rfind(Lines[i].data, Search_term)
+      if pos then
+        Cursor1.line = i
+        Cursor1.pos = pos
+        break
+      end
+    end
+  end
+  if pos == nil then
+    Cursor1.line = Search_backup_cursor1.line
+    Cursor1.pos = Search_backup_cursor1.pos
+  end
+  if Text.lt1(Cursor1, Screen_top1) or Text.lt1(Screen_bottom1, Cursor1) then
+    Screen_top1.line = Cursor1.line
+    local _, pos = Text.pos_at_start_of_cursor_screen_line()
+    Screen_top1.pos = pos
+  end
+end
+
+function rfind(s, pat, i)
+  local rs = s:reverse()
+  local rpat = pat:reverse()
+  if i == nil then i = #s end
+  local ri = #s - i + 1
+  local rendpos = rs:find(rpat, ri)
+  if rendpos == nil then return nil end
+  local endpos = #s - rendpos + 1
+  assert (endpos >= #pat)
+  return endpos-#pat+1
+end
+
 -- Return any intersection of the region from Selection1 to Cursor1 with the
 -- region between {line=line_index, pos=apos} and {line=line_index, pos=bpos}.
 -- apos must be less than bpos. However Selection1 and Cursor1 can be in any order.
-- 
cgit 1.4.1-2-gfad0