Lua Tables

[Centauri Soldier]

I found a very good reference for tables and thought I'd share it.
http://www.gammon.com.au/forum/?id=6036

table.foreach is a very useful function.

[johnraus]

to the the power of LUA Tables Thnx

[Imagine Programming]

Nice Thread

I should write a metatable tutorial one day, not just for OOP coding in Lua,
but for customizing the indexes/operators/pairs functions etc.

There's so much you can do with Lua tables, there is no real limit actually.

[Sakuya]

Nice Thread

I should write a metatable tutorial one day, not just for OOP coding in Lua,
but for customizing the indexes/operators/pairs functions etc.

There's so much you can do with Lua tables, there is no real limit actually.

I'd like to see that, I'm currently working with a script that uses metatables and it's quite fascinating what it can do.

[Centauri Soldier]

So I'll be the n00b and ask...what's a metatable?

[Imagine Programming]

So I'll be the n00b and ask...what's a metatable?

The metatable contains information about an object, for example, a luatable. You can set functions
and data here that belongs to just the object and can't be accessed without calling set/getmetatable.

You can set the type, the getter/setter functions (for tables) and even change how operators react
on certain objects.

For example, you can write code in Lua that causes 'szString * 3' to repeat that string 3 times.
Or e.g.

local newString = ("LoL")*100;

This is a bit complicated stuff, but as Sakuya said, there's so much you can do with it.
This is the reason why, in my Object plugin, you can't loop through the Object table,
you can't change anything in it and why you can use hObjectHandle.Properties.Text = "Test"; etc.

All that is triggered in the metatable

[MadDogDean]

Hey Bas,

Looking forward to the tutorial... Sounds like metatables could be a chapter in one of Stephen Hawkings books on quantum astrophysics

[Imagine Programming]

I think astrophysics are a bit more complicated than this haha
A metatable is just another table attached to a table containing information
about the table it's attached to

[Centauri Soldier]

...A metatable is just another table attached to a table containing information
about the table it's attached to

Oh, ok. That makes sense now. It seems like I could designate and populate my own metatables as well or is it done automatically?

[Imagine Programming]

Oh, ok. That makes sense now. It seems like I could designate and populate my own metatables as well or is it done automatically?

setmetatable(obj,metatable) and metatable = getmetatable(obj)

[dolcevita270301]

Hi all,
Check this link out:
http://blog.tplus1.com/index.php/200...able-examples/

[Imagine Programming]

Nice link, but that's the very basic information regarding indexes in metatables. I will
see if I can put up a tutorial based on the system Object is using, including filtering
allowed keys and values.

[johnraus]

I found a very good reference for tables and thought I'd share it.
http://www.gammon.com.au/forum/?id=6036

table.foreach is a very useful function.

small remark from the LUA 5.1 ref manual:

Functions table.foreach and table.foreachi are deprecated.
You can use a for loop with pairs or ipairs instead.

www.lua.org/manual/5.1/manual.html#7

[Imagine Programming]

John,

That's true, however those functions can be customized and you
can make custom pairs functions. But then again, this can also be
done in the metatables