Lua What is a callback function?

[Digital]

How do callback functions work in scripts and is the behavior the same for each type of script?

 

[Leftwing]

http://javascriptissexy.com/understand-javascript-callback-functions-and-use-them/

A JavaScript resource, but callbacks are a common concept in interpreted languages, like LUA.

Callback Functions in Lua

Better explanation of what is possible with Lua specifically.

It's just a function called within a function, however given the power of this + closures, there are a lot of capabilities and uses for callbacks in our code. callbacks can be predefined or anonymous functions, which is possible because of the lambda calculus property.

A common example is in NPC scripts:

keywordHandler:addGreetKeyword({'hi'}, StdModule.say, {npcHandler = npcHandler, text = 'Hello, |PLAYERNAME|! I have already heard about you! As our newest member you are eligible to be granted a weapon of your {choice}?'}, checkStorageNotSet  )

In this case, checkStorageNotSet is a locally defined function that returns if the desired storage location has a value other than -1, and if it doesn't, output this line.

Basically the result of checkStorageNotSet determines if I output the NPC text.

 

[tokenzz]

Programming in Lua : 6