opencomputers coroutine event microkernel

test_coroutine5.lua

--[[

Establishing ground:

write a generic coroutine kernel loop, event requests pass back to the main
control loop

also lets write 2 coroutines, and manage a list of them

RESULT:


]]

local term = require("term")
local event = require("event")

term.clear()

local function pullEvent(evt)
  return coroutine.yield(evt)
end

-- this function will exit when 'q' is pressed
local function keyboardExitThreadlet()
  print ("starting thread!, press q for this thread to die")
  while true do
    local evt, addr, a, b, c, d, e, f = pullEvent('key_up')
    -- q pressed filter, lets exit!
    if evt == "key_up" and a == 113 then
      break
    end
  end
end

-- this function will print bang
local function keyboardBangThreadlet()
  print ("starting thread!, press b for bang!")

  local w,h = term.getViewport()
  while true do
    local evt, addr, a, b, c, d, e, f = pullEvent('key_up')
    -- q pressed filter, lets exit!
    if evt == "key_up" and a == 98 then
      local col = (w - 4) * math.random()
      local row = (h - 3) * math.random()
      term.setCursor(col + 1, row + 2)
      term.write("BANG")
    end
  end
end

local function eventSpyThreadlet()
  local w,h = term.getViewport()
  while true do
    local evt = {pullEvent()}
    local evtStr = ""
    for i,v in ipairs(evt) do
      evtStr = evtStr .. tostring(v) .. " "
    end

    term.setCursor(1, h)
    term.write("EVT: " .. evtStr .. "                                                               ")
  end
end

-- runs all threads until a thread exists
function threadletKernel(...)
  local threadlets = {}
  local threadletFuncs = {...}

  function threadletHandlerFactory(func)
    local co = coroutine.create(func)
    local evt_filter_name = nil

    return {
      co = co,
      resume = function(evt_data)
        local evt_name = nil
        if evt_data ~= nil then
          evt_name = evt_data[1]
        end

        if evt_filter_name ~= nil and evt_name ~= evt_filter_name then
          return
        end

        if evt_data == nil then
          evt_data = {}
        end

        local noErr, evt_filter = coroutine.resume(co, table.unpack(evt_data))
        evt_filter_name = evt_filter
      end
    }
  end

  for i, func in ipairs(threadletFuncs) do
    threadlets[i] = threadletHandlerFactory(func)
  end

  local threadCount = #threadlets
  local evt_data
  while true do
    for i = 1, #threadlets do
      threadlets[i].resume(evt_data)
    end

    for i = #threadlets, 1, -1 do
      if coroutine.status(threadlets[i].co) == 'dead' then
        table.remove(threadlets, i)
      end
    end

    if #threadlets < threadCount then
      break
    end

    evt_data = {event.pull()}
  end
end

print("press q to exit")
threadletKernel(keyboardExitThreadlet, keyboardBangThreadlet, eventSpyThreadlet)