Resetting all of Löve's callbacks?

[Germanunkol]

Here's the scenario:
In some cases (for example, when the user is using the wrong Löve version), I want to overwrite all callbacks, display something else (an error message) and exit on any key. That's very simple to do, like so (pseudocode, untested, but you get the idea):

Code: Select all

function checkLoveVersion()
    local major, minor, revision, codename = love.getVersion( )
    if minor != 9 then
         love.draw = function()
               love.graphics.print( "Using wrong löve version! Need Version 0.9", 10, 10 )
          end
         love.keypressed = love.quit
     end
end

As long as I call this function after defining my normal draw and keypressed event, I should be fine.
However, I want to avoid that some other callback (for example, textinput) is still present, so I have to manually set all of those to nil. Is there a way to do this automatically? I want to make sure this works over all love versions and future versions as well, and I want to make sure I don't forget some callback.
I'm thinking something like (of course this won't work, because the callbacks aren't in the "callbacks" table):

Code: Select all

for i, c in pairs( love.callbacks ) do
    love.callbacks[i] = nil
end

[s-ol]

Lol, I accidentally sent a PM.
For everyone else:

Code: Select all

for _,v in ipairs{"textinput","update","mousepressed",...} do
  love[v] = nil
end

[Germanunkol]

Hm, that's nice code. However it's not really what I want to do. The problem I was having is: for future versions of Löve there are probably going to be more callbacks which don't exist yet. With your code, I still have to manually set the names of the callbacks which I want to reset. And I'm "scared" I will forget to add future callbacks and then the game will crash when these callbacks happen but the engine has the wrong version.

What I'm looking for is more something like a function love.reset() which resets all current callbacks.
But I guess I'll have to go the "manual" way.

[s-ol]

Hm, that's nice code. However it's not really what I want to do. The problem I was having is: for future versions of Löve there are probably going to be more callbacks which don't exist yet. With your code, I still have to manually set the names of the callbacks which I want to reset. And I'm "scared" I will forget to add future callbacks and then the game will crash when these callbacks happen but the engine has the wrong version.

What I'm looking for is more something like a function love.reset() which resets all current callbacks.
But I guess I'll have to go the "manual" way.

Most of the callbacks are in a table called love.handlers:

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love.handlers
{focus = function() --[[..skipped..]] end, gamepadaxis = function() --[[..skipped..]] end, gamepadpressed = function() --[[..skipped..]] end, gamepadreleased = function() --[[..skipped..]] end, joystickadded = function() --[[..skipped..]] end, joystickaxis = function() --[[..skipped..]] end, joystickhat = function() --[[..skipped..]] end, joystickpressed = function() --[[..skipped..]] end, joystickreleased
= function() --[[..skipped..]] end, joystickremoved = function() --[[..skipped..]] end, keypressed = function() --[[..skipped..]] end, keyreleased = function() --[[..skipped..]] end, mousefocus = function() --[[..skipped..]] end, mousemoved = function() --[[..skipped..]] end, mousepressed = function() --[[..skipped..]] end, mousereleased = function() --[[..skipped..]] end, quit = function() --[[..skipped..]]
end, resize = function() --[[..skipped..]] end, textedit = function() --[[..skipped..]] end, textinput = function() --[[..skipped..]] end, threaderror = function() --[[..skipped..]] end, visible = function() --[[..skipped..]] end} --[[table: 0x41a73f98]]

I think that are actually all except for love.update, love.draw and love.run (which isn't really a callback and can't be changed anyway)

[Evine]

A simple assert seems to be the best solution here. Unless you want to continue running the game after the "error"

Code: Select all

function checkLoveVersion()
    local major, minor, revision = love.getVersion( )
    assert(major == 0 and minor == 9 and revision == 2 , "Wrong Love version" )
end

Take a look at the love.errhand function. To see how love handles errors by default. (There's really no magic to it. Just pure lua code)
https://www.love2d.org/wiki/love.errhand

[bartbes]

love.run (which isn't really a callback and can't be changed anyway)

But.. it can be changed.

[slime]

when the user is using the wrong Löve version, I want to overwrite all callbacks, display something else (an error message)

In that specific case, LÖVE will already display a notice if the version you set in love.conf isn't compatible with the running LÖVE version.

[s-ol]

love.run (which isn't really a callback and can't be changed anyway)

But.. it can be changed.

after it has started?

[bartbes]

Well, no, but that goes for every callback (they just end much more often).

[s-ol]

Well, no, but that goes for every callback (they just end much more often).

Yeah. What I was saying was that there is no point in resetting love.run in case of some error; it won't ever be restarted.