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Types of values
Lua is a dynamically typed language. There is no defined variable type in the language. This allows each value to carry its own type.
As you have noticed, values can be stored in variables. They can be manipulated to give a value of any type. This also allows you to pass arguments to other functions and have them returned as results.
The basic types of values that you'll deal with are as follows:
- Nil: This is the only type whose value is
nil. Any uninitialized variable hasnilas its value. Like global variables, it isnilby default and can be assignednilto delete it. - Boolean: This type has two values:
falseandtrue. You will notice that conditional expressions considerfalseandnilas false and anything else astrue. - Numbers: These represent real (double-precision, floating-point) numbers.
- String: This is a sequence of characters. 8-bit characters and embedded zeroes are allowed.
- Tables: These are data structures in Lua. They are implemented by an associative array, which is an array that can be indexed not only with numbers, but also with strings or any other value, except
nil(more information on this later in this chapter called Tables). - Functions: These are known as first-class values of Lua. Typically, functions can be stored in variables, passed as arguments to other functions, and returned as results.