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Lua Quick Start Guide

You're reading from   Lua Quick Start Guide The easiest way to learn Lua programming

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Product type Paperback
Published in Jul 2018
Publisher Packt
ISBN-13 9781789343229
Length 202 pages
Edition 1st Edition
Languages
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Author (1):
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Gabor Szauer Gabor Szauer
Author Profile Icon Gabor Szauer
Gabor Szauer
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Toc

Meta tables

In Lua, meta tables can be used to modify the behavior of tables. Any table can be made into a meta table, and any table can have a meta table. Even meta tables can have their own meta tables. Meta tables change the behavior of tables using meta methods. These meta methods are functions with a specific name that affect how a table behaves.

First, create a table named meta. For now, this is a normal table. This table will have a function named __add. __add is a reserved function name. The __add function will take two arguments.

The left argument will be a table with a field called value, the right argument will be a number:

meta = { } -- Creates table
meta.__add = function(left, right) -- adds meta method
return left.value + right -- left is assumed to be a table.
end

Next, make a table called container. The container table will have a variable called value, with a...

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