-----------------------------------------------------------------------
-- Tabs to spaces (EditPad-style) for SciTE (self-contained)
-- Kein-Hong Man <khman@users.sf.net> 20040727
-- This program is hereby placed into PUBLIC DOMAIN
-----------------------------------------------------------------------
-- Best installed as a shortcut key, e.g. Ctrl-1 with the following in
-- your user properties file, usually SciTEUser.properties:
--     command.name.1.*=Tabs to Spaces
--     command.subsystem.1.*=3
--     command.1.*=TabToSpace
--     command.save.before.1.*=2
-- This Lua function itself should be in SciTEStartup.lua, assuming it
-- is properly set up. Consult SciTEDoc.html if you are unsure of what
-- to do. You can also keep it in a separate file and load it using:
--     require(props["SciteUserHome"].."/SciTE_TabSpace.lua")
-- Tested on SciTE 1.61+ (CVS 20040718) on Win98SE. Be careful when
-- tweaking it, you *may* be able to crash SciTE. You have been warned!
-----------------------------------------------------------------------
-- This is useful if you often copy text over to a word processor for
-- printing. Word processors have tabs based on physical lengths, so
-- indentation of source code would usually start to run. The current
-- tab width can be overridden using a global property:
--     ext.lua.tabtospace.tabsize=8
-----------------------------------------------------------------------
TabToSpace = function()
  -- get override or editor's current tab size
  local tab = tonumber(props["ext.lua.tabtospace.tabsize"])
  if not tab then tab = editor.TabWidth end
  editor:BeginUndoAction()
  for ln = 0, editor.LineCount - 1 do
    local lbeg = editor:PositionFromLine(ln)
    local lend = editor.LineEndPosition[ln]
    local text = editor:textrange(lbeg, lend)
    local changed = false
    while true do
      local x, y = string.find(text, "\t", 1, 1)
      if x then -- found tab, replace
        local z = x - 1 + tab
        y = z - math.mod(z, tab) + 1 -- tab stop position
        text = string.sub(text, 1, x - 1) ..
               string.rep(" ", y - x) ..
               string.sub(text, x + 1)
        changed = true
      else -- no more tabs
        break
      end
    end--while
    if changed then
      editor.TargetStart = lbeg
      editor.TargetEnd = lend
      editor:ReplaceTarget(text)
    end
  end--for
  editor:EndUndoAction()
end

-----------------------------------------------------------------------
-- Spaces to tabs (EditPad-style) for SciTE (self-contained)
-- Kein-Hong Man <khman@users.sf.net> 20040727
-- This program is hereby placed into PUBLIC DOMAIN
-----------------------------------------------------------------------
-- Best installed as a shortcut key, e.g. Ctrl-1 with the following in
-- your user properties file, usually SciTEUser.properties:
--     command.name.1.*=Spaces to Tabs
--     command.subsystem.1.*=3
--     command.1.*=SpaceToTab
--     command.save.before.1.*=2
-- This Lua function itself should be in SciTEStartup.lua, assuming it
-- is properly set up. Consult SciTEDoc.html if you are unsure of what
-- to do. You can also keep it in a separate file and load it using:
--     require(props["SciteUserHome"].."/SciTE_TabSpace.lua")
-- Tested on SciTE 1.61+ (CVS 20040718) on Win98SE. Be careful when
-- tweaking it, you *may* be able to crash SciTE. You have been warned!
-----------------------------------------------------------------------
-- Converts spaces to tabs, based on the current or given tab size.
-- Removes redundant spaces within sentences as well. Converts trailing
-- spaces to tabs where appropriate, but does not delete them. The
-- current tab width can be overridden using a global property:
--     ext.lua.spacetotab.tabsize=8
-----------------------------------------------------------------------
SpaceToTab = function()
  -- get override or editor's current tab size
  local tab = tonumber(props["ext.lua.spacetotab.tabsize"])
  if not tab then tab = editor.TabWidth end
  -- computes next tab stop, using column value from 0
  local SpaceToNextStop = function(col)
    local z = col + tab
    return tab - math.mod(z, tab)
  end
  -- loop for each line
  editor:BeginUndoAction()
  for ln = 0, editor.LineCount - 1 do
    local lbeg = editor:PositionFromLine(ln)
    local lend = editor.LineEndPosition[ln]
    local text = editor:textrange(lbeg, lend)
    local changed = false
    local x = 1, y, z
    local col = 0
    while x <= string.len(text) do
      c = string.byte(text, x)
      if c == 9 then -- tab
        col = col + SpaceToNextStop(col)
        x = x + 1
      elseif c == 32 then -- space
        y, z = string.find(text, " +", x)
        y = z - y + 1 -- number of spaces found
        z = SpaceToNextStop(col)
        if y >= z then
          -- if spaces past a tab stop, convert to a single tab
          if z > 1 then -- convert spaces to tab if >1 space
            col = col + z
            text = string.sub(text, 1, x - 1) .. "\t" ..
                   string.sub(text, x + z)
            x = x + 1
            changed = true
          else -- leave a single space be
            x = x + 1
            col = col + 1
          end
        else -- y < z
          -- if there's a following tab, spaces are redundant
          if string.byte(text, x + y) == 9 then -- got a tab
            col = col + z
            text = string.sub(text, 1, x - 1) ..
                   string.sub(text, x + y)
            changed = true
          else -- no following tab, leave them be
            x = x + y
            col = col + y
          end
        end
      else -- normal char
        x = x + 1
        col = col + 1
      end
    end--while
    if changed then
      editor.TargetStart = lbeg
      editor.TargetEnd = lend
      editor:ReplaceTarget(text)
    end
  end--for
  editor:EndUndoAction()
end
-- end of script