Editing Callback (computer programming) (section)

===Lua===
In this [[Lua]] code, function {{code|calculate}} accepts the {{code|operation}} parameter which is used as a blocking callback. {{code|calculate}} is called with both {{code|add}} and {{code|multiply}}, and then uses an [[anonymous function]] to divide. 

<syntaxhighlight lang="lua">function calculate(a, b, operation)
    return operation(a, b)
end

function multiply(a, b)
    return a * b
end

function add(a, b)
    return a + b
end

print(calculate(10, 20, multiply)) -- outputs 200
print(calculate(10, 20, add)) -- outputs 30
-- an example of a callback using an anonymous function
print(calculate(10, 20, function(a, b)
    return a / b -- outputs 0.5
end))</syntaxhighlight>