Checkpoint - A work around for persistence

local checkpoint = dofile(shell.dir().."/checkpoint.lua") --# Checkpoint can also be loaded with require and os.loadAPI

-- DEMO FLAGS

local doTerminateTest = true --# boolean

local doCheckpointRemoveTest = false --# boolean

local doErrorInCallbackTest = false --# boolean

local useCheckpointErrorTrace = false --# boolean

local checkpointFileName = nil --# nil or string, nil for default, string should be absolute path

-- END OF DEMO FLAGS

local args = {...}


--# Checkpoint works using callbacks, we define a bunch here with inventive names like t, c and d
local function t(...)
  print(table.concat({...}, " ")) --# just test code
  args = {"test"} --# notice that this doesn't effect anything, although
  checkpoint.reach("second") --# this tells Checkpoint what to run next, checkpoint.reach returns whatever the callback returns
end

local function c(...)
  print(table.concat({...}, " "))
 
  print("Queuing terminate event, rerun program for next part of test")
  if doTerminateTest then
    os.queueEvent("terminate")
  end
  checkpoint.reach("third")
end

local function d()
  print("Terminate?")
  sleep(0.001) --# catch that terminate if we are on first run, second run won't have a terminate
  print("I'll take that as no")
 
  if doErrorInCallbackTest then
    error("doErrorInCallbackTest")
  end
 
  if doCheckpointRemoveTest then
    checkpoint.remove("third") --# removing checkpoints is more of a debug thing to make sure that your program is flowing in the right direction
    print("removing third checkpoint, prepare for error")

	 checkpoint.reach("third")
  end
  return "return test"
end

--# here we define our checkpoints under the following format:
--#   label - this is the name of the checkpoint and what your program will need to use to refer to it
--#   callback - this is the function which gets called when checkpoint.reach is given the corresponding label
--#   callback args - these are the values passed to the callback when it gets called

checkpoint.add("start", t, 1, unpack(args))

checkpoint.add("second", c, 2, unpack(args))

checkpoint.add("third", d)


local r = checkpoint.run("start", checkpointFileName, useCheckpointErrorTrace) --# identifies if your program needs to continue or starts from given label if it doesn't

print(tostring(r)) --# checkpoint.run returns whatever the last checkpoint callback does

local checkpoint = require "checkpoint"

local function c1() --# first callback
  print("1")
  checkpoint.reach("second")
  --# danger zone
  print("2")
end
checkpoint.add("first", c1)

local function c2() --# second callback
  print("3")
end
checkpoint.add("second", c2)

checkpoint.run("first")

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• Better errors, particularly with tracebacks. If it's the program which is causing the error then I would like the error to message to blame it correctly. If anyone knows how to do this I would appreciate the help.
• Rewrite: see if I can avoid "function chaining", idea: checkpoint.reach sets a nextCheckpoint value and returns instead of calling the next callback, when checkpoint.run sees this it runs that next checkpoint after setting to nil, if the next one is nil then assume program end This may help improve errors or at lease make implementing improvements to the error reporting easier. I'll look into this when it's not 1:23 AM

Lupus590, on 21 March 2018 - 01:10 AM said:

Better errors, perticually with tracebacks. If it's the program which is cauing the error then I would like the error to message to blame it correctly. If anyone knows how to do this I would appreciate the help.

apemanzilla, on 21 March 2018 - 01:13 AM said:

Lupus590, on 21 March 2018 - 01:10 AM said:

Better errors, perticually with tracebacks. If it's the program which is cauing the error then I would like the error to message to blame it correctly. If anyone knows how to do this I would appreciate the help.

You can use trace for that

-- Not to bothered that this doesn't work
-- setmetatable(checkpoint, {__call = checkpoint.reach}) -- allow checkpoints to be reached via checkpoint(label) as well as checkpoint.reach(label)

__call = function(self, ...) end

setmetatable(checkpoint, {__call = function(_, ...) checkpoint.reach(...) end})

Incinirate, on 21 March 2018 - 01:35 AM said:

setmetatable(checkpoint, {__call = function(_, ...) checkpoint.reach(...) end})

Lupus590, on 21 March 2018 - 01:18 AM said:

apemanzilla, on 21 March 2018 - 01:13 AM said:

Lupus590, on 21 March 2018 - 01:10 AM said:

Better errors, perticually with tracebacks. If it's the program which is cauing the error then I would like the error to message to blame it correctly. If anyone knows how to do this I would appreciate the help.

You can use trace for that

I've been using the error tracing built into mbs and it doesn't blame the callbacks when I think it should.

Edit: trace gives the same error trace

local checkpoint = require "checkpoint"

local function c1() --# first callback
  print("1")
  checkpoint.reach("second")
  print("2")
end
checkpoint.add("first", c1)

local function c2() --# second callback
  print("3")
end
checkpoint.add("second", c2)

checkpoint.run("first")

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