control tab mru

By default, when you press Control+TAB or Control+Shift+TAB, Textadept switch to the next/previous buffer in the order shown in the tab-bar.

The following code implements a more standard way to handle those key combinations: it travels the buffers in Most Recent Use order (you can choose any file by holding the control key down and pressing the TAB or shift+TAB keys several times before releasing the control key).

Copy the following code in your ~/.textadept/init.lua to modify the control+tab behavior:

-------------- ctrl+tab / ctrl+shift+tab MRU --------------------
--HOLD control key DOWN and press tab = goto previous used buffers (MRU list)
-- ctrl+tab       : forward
-- ctrl+shift+tab : backwards
--example with 5 buffers: CONTROL pressed, TAB pressed 5 times, CONTROL released
--  tab tab tab tab tab
-- 1-  2-  3-  4-  5^  1
-- 2-  1   1   1   1^  2
-- 3   3-  2   2   2^  3
-- 4   4   4-  3   3^  4
-- 5   5   5   5-  4^  5
--
local ctrl_key_down = false
local tab_mru_idx= 0
local mru_buff= {}

local function mru_getbuffpos(b)
  --locate buffer 'b' in the MRU list
  local i= 1
  while i <= #mru_buff do
    if mru_buff[i] == b then
      return i  --return buffer position: 1...
    end
    i=i+1
  end
  return 0  --not found
end

local function mru_buftotop(b)
  --move/add buffer 'b' to the TOP of the MRU list
  if b ~= nil then
    local i= mru_getbuffpos(b)
    if i == 0 then
      --not on the list, add it
      i=#mru_buff+1
      mru_buff[i]= b
    end
    if i > 1 then
      while i > 1 do
        mru_buff[i]= mru_buff[i-1]
        i=i-1
      end
      mru_buff[1]= b
    end
  end
end

--control+tab handler
local function mru_ctrl_tab_handler(shift)
  --we need 2 or more buffers to swap
  if #mru_buff < 2 then
    return --not enought buffers
  end

  if ctrl_key_down then
    --CONTROL key was pressed before 'this' TAB
    --START A NEW SWAP CYCLE
    tab_mru_idx= 1
    ctrl_key_down = false
  end

  local swap
  if shift then
    --ctrl+shift+ tab + .. + tab: swap 'backwards'
    swap= tab_mru_idx
    tab_mru_idx= tab_mru_idx-1
    if swap < 2 then
      tab_mru_idx= #mru_buff
      swap=0
      --ROTATE DOWN (bring bottom to top)
      mru_buftotop(mru_buff[#mru_buff])
    end
  else
    --ctrl+ tab +..+ tab: swap 'foreward'
    tab_mru_idx= tab_mru_idx+1
    swap= tab_mru_idx
    if tab_mru_idx > #mru_buff then
      tab_mru_idx= 1
      swap=0
      --ROTATE UP (send top to bottom)
      local b= mru_buff[1]
      local i= 1
      while i < #mru_buff do
        mru_buff[i]= mru_buff[i+1]
        i=i+1
      end
      mru_buff[i]= b
    end
  end

  if swap > 0 then
    --SWAP 'swap' and top (pos=1)
    --to prevent buffer pushing in BUFFER_AFTER_SWITCH
    local b= mru_buff[1]
    mru_buff[1]= mru_buff[swap]
    mru_buff[swap]= b
  end
  --activate the buffer in the TOP of the MRU list
  view:goto_buffer(mru_buff[1])
end
keys['ctrl+\t'] = function() mru_ctrl_tab_handler(false) end
keys['ctrl+shift+\t']= function() mru_ctrl_tab_handler(true) end

events.connect(events.KEYPRESS, function(code, shift, control, alt, meta)
  if code == 0xFFE3 or code == 0xFFE4 then --control key pressed? (left=65507=FFE3, right=65508=FFE4)
    ctrl_key_down = true
  end
end )

events.connect(events.BUFFER_AFTER_SWITCH, function()
  --move the current buffer to the TOP of the MRU list, pushing down the rest
  mru_buftotop(buffer)
end)

events.connect(events.BUFFER_NEW, function()
  --add a new buffer to the TOP of the MRU list
  --keep in mind that this event is also fired when TA starts
  if #_BUFFERS > #mru_buff then
    mru_buftotop(buffer)
  end
end)

events.connect(events.BUFFER_DELETED, function()
  --remove the closed buffer from the MRU list
  --this event is called AFTER the buffer was deleted (the deleted buffer is NOT in the top of the MRU list)
  --is safer to check ALL the buffers and remove from the MRU list the ones that don't exist any more
  local i= 1
  while i <= #mru_buff do
    if mru_buff[i] ~= nil then
      if _BUFFERS[mru_buff[i]] == nil then
        --this buffer was deleted, remove it from the list
        local j= i
        while j < #mru_buff do
          mru_buff[j]= mru_buff[j+1]
          j=j+1
        end
        mru_buff[j]= nil
      end
      i=i+1
    end
  end
end)

--load existing buffers in the MRU list
if #_BUFFERS > 0 then
  local nb= #_BUFFERS
  local i= 1
  while nb > 0 do
    mru_buff[i]= _BUFFERS[nb]
    nb=nb-1
    i=i+1
  end
  --bring the current buffer to the top of the list
  mru_buftotop(buffer)
end

git-hub: gabdub/ta-tweaks