1 files changed, 0 insertions, 110 deletions
diff --git a/undo.lua b/undo.lua
deleted file mode 100644
index 873feea..0000000
--- a/undo.lua
+++ /dev/null
@@ -1,110 +0,0 @@
--- undo/redo by managing the sequence of events in the current session
--- based on https://github.com/akkartik/mu1/blob/master/edit/012-editor-undo.mu
-
--- Incredibly inefficient; we make a copy of lines on every single keystroke.
--- The hope here is that we're either editing small files or just reading large files.
--- TODO: highlight stuff inserted by any undo/redo operation
--- TODO: coalesce multiple similar operations
-
-function record_undo_event(State, data)
-  State.history[State.next_history] = data
-  State.next_history = State.next_history+1
-  for i=State.next_history,#State.history do
-    State.history[i] = nil
-  end
-end
-
-function undo_event(State)
-  if State.next_history > 1 then
---?     print('moving to history', State.next_history-1)
-    State.next_history = State.next_history-1
-    local result = State.history[State.next_history]
-    return result
-  end
-end
-
-function redo_event(State)
-  if State.next_history <= #State.history then
---?     print('restoring history', State.next_history+1)
-    local result = State.history[State.next_history]
-    State.next_history = State.next_history+1
-    return result
-  end
-end
-
--- Copy all relevant global state.
--- Make copies of objects; the rest of the app may mutate them in place, but undo requires immutable histories.
-function snapshot(State, s,e)
-  -- Snapshot everything by default, but subset if requested.
-  assert(s)
-  if e == nil then
-    e = s
-  end
-  assert(#State.lines > 0)
-  if s < 1 then s = 1 end
-  if s > #State.lines then s = #State.lines end
-  if e < 1 then e = 1 end
-  if e > #State.lines then e = #State.lines end
-  -- compare with App.initialize_globals
-  local event = {
-    screen_top=deepcopy(State.screen_top1),
-    selection=deepcopy(State.selection1),
-    cursor=deepcopy(State.cursor1),
-    lines={},
-    start_line=s,
-    end_line=e,
-    -- no filename; undo history is cleared when filename changes
-  }
-  -- deep copy lines without cached stuff like text fragments
-  for i=s,e do
-    local line = State.lines[i]
-    table.insert(event.lines, {data=line.data})  -- I've forgotten: should we deepcopy(line.data)?
-  end
-  return event
-end
-
-function patch(lines, from, to)
---?   if #from.lines == 1 and #to.lines == 1 then
---?     assert(from.start_line == from.end_line)
---?     assert(to.start_line == to.end_line)
---?     assert(from.start_line == to.start_line)
---?     lines[from.start_line] = to.lines[1]
---?     return
---?   end
-  assert(from.start_line == to.start_line)
-  for i=from.end_line,from.start_line,-1 do
-    table.remove(lines, i)
-  end
-  assert(#to.lines == to.end_line-to.start_line+1)
-  for i=1,#to.lines do
-    table.insert(lines, to.start_line+i-1, to.lines[i])
-  end
-end
-
-function patch_placeholders(line_cache, from, to)
-  assert(from.start_line == to.start_line)
-  for i=from.end_line,from.start_line,-1 do
-    table.remove(line_cache, i)
-  end
-  assert(#to.lines == to.end_line-to.start_line+1)
-  for i=1,#to.lines do
-    table.insert(line_cache, to.start_line+i-1, {})
-  end
-end
-
--- https://stackoverflow.com/questions/640642/how-do-you-copy-a-lua-table-by-value/26367080#26367080
-function deepcopy(obj, seen)
-  if type(obj) ~= 'table' then return obj end
-  if seen and seen[obj] then return seen[obj] end
-  local s = seen or {}
-  local result = setmetatable({}, getmetatable(obj))
-  s[obj] = result
-  for k,v in pairs(obj) do
-    result[deepcopy(k, s)] = deepcopy(v, s)
-  end
-  return result
-end
-
-function minmax(a, b)
-  return math.min(a,b), math.max(a,b)
-end