Intercepting Events

KingofGamesYami, on 20 November 2015 - 12:15 AM said:

Sure, just overwrite coroutine.yeild.

CoderPuppy, on 20 November 2015 - 12:34 AM said:

That would break any program that uses coroutines and doesn't just pass events through.

os.pullEventRaw = function( ... )
	return coroutine.yield( ... )
end

os.pullEventRaw = function( ... )
    local e = { coroutine.yield( ... ) } --# Call coroutine.yield, which is what os.pullEventRaw usually is using( so no need to backup the function )

    --# Handle the events here
    if e[1] == "key" then
        if e[2] == keys.enter then
            print( "The enter key was pressed" )
        elseif e[2] == keys.tab then --# The tab key was pressed
            e[2] = keys.enter --# Change it to the enter key instead
        end
    end

    return unpack( e ) --# Return the event
end

CoderPuppy, on 20 November 2015 - 12:34 AM said:

and doesn't just pass events through.

function test()
  local co = coroutine.create(function()
    print(coroutine.yield('world'))
  end)
  local ok, res = coroutine.resume(co)
  local ok = coroutine.resume(co, 'hello ' .. res)
end

--# try it before the override
test()
--# says 'hello world'

local oldYield = coroutine.yield
function coroutine.yield(...)
  local res = {oldYield(...)}
  if res[1] == 'hello world' then
    return 'broken'
  else
    return unpack(res)
  end
end

--# try it after the override
test()
--# says 'broken'

function test()
  local co = coroutine.create(function()
    print(coroutine.yield())
  end)
  local ok, res = coroutine.resume(co)
  local ok = coroutine.resume(co, io.read('*l'))
end
--# type in 'key'
--# it says 'key'
test()
local oldYield = coroutine.yield
function coroutine.yield(...)
  local res = {oldYield(...)}
  if res[1] == 'key' then
    return 'broken'
  else
    return unpack(res)
  end
end
--# type in 'key'
--# it says 'broken'
test()

KingofGamesYami, on 20 November 2015 - 02:31 AM said:

Again, the definition of an event is data passed to coroutine.yield.

local oldYield = coroutine.yield
function coroutine.yield(...)
  local res = {oldYield(...)}
  if res[1] == "key" and res[2] == keys.tab then
    return "key", keys.enter
  else
    return unpack(res)
  end
end

Bomb Bloke, on 20 November 2015 - 02:57 AM said:

snip