1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
-- 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),
current_drawing_mode=Drawing_mode,
previous_drawing_mode=State.previous_drawing_mode,
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]
if line.mode == 'text' then
table.insert(event.lines, {mode='text', data=line.data})
elseif line.mode == 'drawing' then
local points=deepcopy(line.points)
--? print('copying', line.points, 'with', #line.points, 'points into', points)
local shapes=deepcopy(line.shapes)
--? print('copying', line.shapes, 'with', #line.shapes, 'shapes into', shapes)
table.insert(event.lines, {mode='drawing', h=line.h, points=points, shapes=shapes, pending={}})
--? table.insert(event.lines, {mode='drawing', h=line.h, points=deepcopy(line.points), shapes=deepcopy(line.shapes), pending={}})
else
print(line.mode)
assert(false)
end
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
|