lua objects?

[Carl]

Hi I'm new to LUA after coming from javascript/c# background. At this stage I'm just familiarizing my self with LUA and love but I'm curious as to how I go about creating custom objects?

For example in javascript I could create an object such as "player" then from that I can do stuff like player.speed = 10; Is something like that possible in LUA and if so how do I go about doing it?

Thanks

[Robin]

Not only can you do that, in Lua it's very very easy:

Code: Select all

player = {}

There. You have made a new table, and bound the name "player" to it. Now you can set player.speed = 10. You can also set entries at table creation time:

Code: Select all

player = {speed = 10}

Tables can be used as objects, classes, arrays and much more.

I recommend reading Programming in Lua (http://www.lua.org/pil/index.html).

[Carl]

Amazing! I did read about tables but assumed they were only to be used as arrays, turns out they got unlimited uses!

[osgeld]

yep, you can even stuff functions in them for class like structures

[Fizzadar]

I used to think tables == arrays, but then I discovered the use of

table:Something( lol ) will basically allow you to use self inside and ... I just feel all gewy inside

Lua is awesome!

[subrime]

but it doesn't stop there... you can also set up a __call function in the metatable and then use the table the same way as a function (while still keeping all its other awesomeness):

Code: Select all

t={}
t.note='associative arrays'
meta={__call=function(self,x) print(self.note..' and metatables are '..tostring(x)) end}
setmetatable(t,meta)
t('awesome!')
>associative arrays and metatables are awesome!

[kikito]

Hi Carl,

Lua is so flexible that by using metatables and metamethods it is possible to replicate C#/Java classes and instances functionality (also inheritance, mixins...)

I've done so in my PÄSSION lib (http://love2d.org/forum/viewtopic.php?f=5&t=1039). Concretely, the part that implements Object Orientation is a 100-lines file called "MiddleClass.lua" (It has its own google project page: http://code.google.com/p/lua-middleclass/)

Finally, there's more information about "traditional" object orientation in Lua on the Lua-users wiki: http://lua-users.org/wiki/ObjectOrientedProgramming

Regards!

[kikito]

Hi again,

I've created a wiki page for MiddleClass, with examples and everything, if you are still interested on this stuff.

Regards!