middleclass & extras: middleclass 3.0 is out!

[kikito]

This is wrong:

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TimedBox = class('TimedBox')
TimedBox:subclass('MessageBox')

The correct way of creating a subclass it is one of this two:

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TimedBox = class('TimedBox', MessageBox)

-- or --

TimedBox = MessageBox:subclass('TimedBox')

Your code doesn't throw any errors because it is doing non-erroneous things:

• TimedBox = class('TimedBox') Creates a new class (a subclass of Object)
• TimedBox:subclass('MessageBox') is creating a subclass of TimedBox, called MessageBox. It is also returning it, but no variable receives it.

The other thing I note is the empty constructor:

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function MessageBox:initialize()

end

Never do that.

All constructors should be either implicit (not appear at all, so they get a default implementation) or, if they are explicit, make a call to super.initialize(self)

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function MessageBox:initialize()
  super.initialize(self) -- always, always do this.
end

Finally, if you are doing that, probably you want to set the text directly on the initialize function, as a parameter. Complete sample:

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MessageBox = class('MessageBox')
MessageBox.DEFAULT_TEXT = "Default"
function MessageBox:initialize(text)
  super.initialize(self) -- always, always do this.
  self.text  = text or self.class.DEFAULT_TEXT -- I prefer this, but you can (for now) do self.DEFAULT_TEXT instead of self.class.DEFAULT_TEXT
end

TimedBox = class('TimedBox', MessageBox) -- subclass
function TimedBox:initialize(text)
  super.initialize(self, text)
end

StayBox = class('StayBox', MessageBox) -- subclass
StayBox.DEFAULT_TEXT = "StayBox" -- I changed the default text for StayBox here
function StayBox:initialize(text)
  super.initialize(self, text)
end

ChoiceBox = class('ChoiceBox', MessageBox) -- subclass
function ChoiceBox:initialize(text)
  super.initialize(self, text)
end

And then for testing:

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function love.load()
  msg = MessageBox:new()
  print(msg.text)
  timed = TimedBox:new("Parameter")
  print(timed.text)
  stay = StayBox:new()
  print(stay.text)
end

Output (disclaimer: I didn't actually test it):

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Default
Parameter
StayBox

I hope this helps!

[TechnoCat]

This is wrong:

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TimedBox = class('TimedBox')
TimedBox:subclass('MessageBox')

The correct way of creating a subclass it is one of this two:

Code: Select all

TimedBox = class('TimedBox', MessageBox)

-- or --

TimedBox = MessageBox:subclass('TimedBox')

I see, so I was doing inheritance wrong.
Thanks for the huge help Kikito.

[TechnoCat]

I'm trying to pass in a function pointer. And setting it to default if nil is passed in.

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Object = class('Object')
function Object:initialize(fnct)
  super.initialize(self)
  defaultFnct = function() return "default" end
  self:fnct() = fnct or defaultFnct
end

Output:

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Syntax error: unexpected symbol near '='

I realize this might end up just being a plain Lua question, but I wasn't sure.

[bartbes]

Well, since : is syntactic sugar, you'll need to do self.fnct = fnct or defaultFnct

[kikito]

I'm trying to pass in a function pointer. And setting it to default if nil is passed in.
...
I realize this might end up just being a plain Lua question, but I wasn't sure.

Yep, the error is on this line:

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self:fnct() = fnct or defaultFnct

self:fnct() is an invocation. It gets transformed into the value it returns before interpreting the expression that contains it. What you wrote, would be equivalent to doing this:

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"default" = fnct or defaultFnct -- assuming that the function returned "default" when invoked

If you want to reference the function, you have to do self.fnct = ... instead.

[kikito]

Small update - I detected and corrected a bug on Stateful. It basically made inncludes(module, aClass) fail on certain occasions (subclasses of a Stateful class).

It is an edge case that I didn't think about before; I believe it also happened when Stateful was called MindState.

In order to correct this bug, you will need to update middleclass as well as middleclass-extras.

On other news, I've started integrating middleclass-extras with PÄSSION. Was able to have the avalanche and physics platformer running. I'm now with piano-piano (which is the most complex one, since it has a complex GUI)

Regards!

[TechnoCat]

What are the rules for including MiddleClass in libraries and games?

[kikito]

You mean, the license?

[TechnoCat]

Well, I see it is BSD, but what does that mean really?

EDIT: and i've been working on this message box system library with middleclass, you should check it out. http://bitbucket.org/dannyfritz/message-in-a-bottle

[kikito]

Well, I see it is BSD, but what does that mean really?

The way I see it, it means 'do whatever you want, but give me credit, and don't use the name to give publicity without my permission'. 'Giving credit' means 'copying the license file somewhere'. You can either have a separate file called middleclass-license.txt or you can just have a single license.txt file with all the licenses you use, one after another. The publicity part is there simply so you can't use the name: "from the creators of MiddleClass, here's a wonderful Snake game!" without permission. That's the way I understand it, at least. I'm not a lawyer.

EDIT: and i've been working on this message box system library with middleclass, you should check it out. http://bitbucket.org/dannyfritz/message-in-a-bottle

Interesting. Can I has screenshots? It is kind of difficult to imagine how it looks.