Intro:⚓︎

In this guide, we will discuss some more stuff about functions. Before proceeding make sure you have some knowledge about the function and conditional statements!

Recursive Function⚓︎

What is recursion/recursive function?⚓︎

Recursion in Lua is very simple. In recursion, a function calls itself until a condition meets, just like a loop! Now you must be thinking about how a function can call itself? So there is an example of how you can do it!

local function recursive(n)
  if n == 6 then
    return n
  end
  print(n)
  n = n + 1
  return recursive(n)
end

recursive(1)

1
2
3
4
5

example:⚓︎

You can use recursion for lots of stuff. To give you an example I made a recursive function that iterates through an array and prints its elements

local tbl = {"eden","blueberry","roblox","lua","kebabs"}
local function iterator(tb,cur_ind)
   local index = cur_ind or 0
   local value = tb[index+1]
   print(value)
   return tb[index+2] and iterator(index+1)
end

iterator(tbl)

eden
blueberry
roblox
lua
kebabs

Anonymous Functions!⚓︎

What is an anonymous function?⚓︎

Anonymous functions are just anonymous, It means that they have no name. We just create them anonymously. Let me give you an example

local function func()
   return function() -- anonymous function
   end
end

In the above example the function func returns an anonymous function. You can cache this anonymous function and then call it.

Closure Function!⚓︎

What is a closure?⚓︎

The closure could be a little complicated but I will try my best to explain you. The first thing you should always remember is: that a closure function is an anonymous function but an anonymous function is not always a closure function.

I will try to explain you with an example!

local function func()
    local number = 2
    return function() -- a closure function
       number = number + 1
       return number
    end
end

local v1 = func()
print(v1())
print(v1())

Output:

3
4

Now you might be confused but no worry I will explain you! So, here are a few points you should know to understand that

1. A closure function always has access to the variables (upvalues) of that function that returned this closure function.
2. If a closure function updates any of those upvalues say it changed the upvalue from "2" to "4", now whenever that closure function is called the value will be "4".

Now if you look back on the code you might start understanding how a closure function works. In the example code, we created the function func. Inside the function, we created a variable number and store 1 in it. After that, we returned a closure function and inside closure, we added 1 in the number variable.

We cached that closure function in a variable v1. Now whenever we call it, it adds "1" to the number variable. For the first time when we called the closure function, the variable "number" had 2 in it. So, after adding it becomes 3 and returned 3. When the closure function was called for the second time the number variable had 3 in it and after adding it became 4. And that's how a closure function works.

Hope you understand it now. If there is still any confusion try reading it again. You might be thinking the closure function is a useless thing but if you are thinking that then you are 200% wrong because closure functions are pretty useful and very important. Using closure you can make cool stuff. just to show you how much useful they are, I made an iterator function just like pairs/ipairs, and here it is:

local function iter(b)
   local ins = 0
   local s
   return function()
      ins += 1
      return b[ins] and ins , b[ins]
   end
end
local tbl = {"edenrose", "hi", "cute", "alive"}
for i,v in iter(tbl) do
   print(i,v)
end

Output:

1 edenrose
2 hi
3 cute
4 alive

Thanks For Reading!⚓︎

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