Tuple and function types

A tuple groups a fixed number of values by position. Each position may have a different type:

local entry: (String, Int) = ("Ada", 42)

The type (String, Int) says that the first item is a String and the second is an Int. The tuple’s length and the type at each position are part of its type, so (String, Int) differs from (Int, String) and from (String, Int, Boolean).

Tuples are useful for small, temporary groupings in which positional meaning is obvious. Prefer a record when fields deserve names or the value forms part of a public model.

Tuple equality is available when equality exists for every element. Values are compared position by position.

Function types

Functions can be stored and passed as values. A function type describes its parameters and results:

function(value: Int): Int

The following local holds an anonymous function matching that type:

local increment: function(value: Int): Int = function(value: Int): Int
    return value + 1
end

local result = increment(41)

Parameter names are written in function types, followed by their types. A function with no result omits the result annotation:

function(message: String)

Function types must match exactly when one callable value is assigned to another. Function values do not support == or ~= because closure identity is not exposed as ordinary value equality.