Basic Tutorial on Lua

[[Shon3m]]

--[[ This is a multi-line comment ]]--

print ("Hello World") -- This is a print command, it prints stuff to the console

-- This is a single line comment. Anything after the two dashes is ignored by Lua

--[[ 2.lua 

This will teach you about setting variables and using them in Lua ]] 

x = 4 -- It's as simple as that. No need to define if x is an integer or string, Lua does that for you 

print (x); -- Small point, Lua DOES NOT REQUIRE semi colons. They can or can't be ued based on user preference 

x = "Hi" -- Now we've set x to a string, which Lua does automagically 

print (x) 

x = false -- Now x is a boolean value 

print (x) 

x = nil -- Lua is amazingly easy to clean up. If you want to clean out memory of unused varibles, set them to nil. 
        -- By default ALL variables are set to nil in Lua, so variables set to nil by the user become nonexistant. 
       
print (x) 


 
--[[ 3.lua 

Simple info printing commands, to help with debugging ]] 

x = 4 

print (x, type(x)) -- type(x) prints out what type of variable x is being processed as. It's bad if you try to add two numbers 
               -- and they turn out to be strings. 
                
-- If you noticed above, it gets printed out weirdly. The distance between 4 and number is huge. That is what the comma does, seperates 
-- things by an amount of space. To make it continuous, we do the following: 

print (x .. type(x)) 

-- The .. means "directly connect". No spaces, nothing. This also looks bad because it's now 4number. So what we would do to make it look pretty... 

print (x .. " " .. type(x)) 


 
--[[ 4.lua 

We learn about one last variable type: The table, which are similar to arrays ]] 

x = {} -- This is how we set up an empty table. All values enclosed by the curly braces become part of the table. 

x = { 1, 2, 3 } -- Separate values with a comma when initializing them in a table 

first = x[1] -- You can assign values from a table to another variable. Unlike most languages, Lua starts it's position at 1, not 0 

print (first) 

test = x[0] 

print (test) -- See? Position 0 doesn't exist. 

-- You can also add values to a table after it's been initialized, like so: 

table.insert(x, 4) -- table.insert (name of table, position to be inserted to (is NOT assumed, so if left empty, it'll just be added to the end), 
                   -- value to input) 

print (x[4]) 

--  Putting two cents together you can do this 

y = {} 

y[1] = "a" 
y[2] = "b" 
y[3] = "c" 

print (y[1] .. ", " .. y[2] .. " and " .. y[3]) 

-- Here, I'll show you how to see the contents of your tables. VERY useful for debugging: 

for i,v in pairs (y) do print (i,v) end -- This says for every position and value, in the pairs of them in table y, print them 

-- You can see it's 3 positions long. But what if you have a huge table and need to know it's size? the pairs loop would be impractical 

# y -- This tells you the size of a given table. # is the operator, y is the table name 

-- So finally say I want spot number two to be filled with "z" instead of "b" 

table.insert (y, 2, "z") 

print (y[2]) 


 
--[[ 5.lua 

If / elseif / else ]] 

switch = false -- Setting the variable 

if (switch == true) then -- The "then" is a very important part of the If / else structure 
   print ("True") 
else 
   print ("False") 
end -- %%%%%%%%%%%%%%%%%%% This is also another major point. At the end of any IF statement block, you must end with 'end" 

-- Sidenote to you first time programmers, this is a common mistake. IF statements use TWO equal signs, not one. :) 

-- In an If / Elseif / Else structure, any line containing "if" or "elseif" must have a "then" after the condition 
-- If Mary is at the bar, then flirt with her. If switch is true, then print true. 

flag = 2 

if (flag == 1) then 
   print ("The flag was 1") 
else if (flag == 2) then 
   print ("The flag was 2") 
else if (flag == 3) then 
   print ("The flag was 3") 
else 
   print ("The flag was " .. flag) 
end -- %%%%%%%%%%%%%%%%%%%%%%%%%%% Ending with "end" at the end of the WHOLE block 

-- Nesting If statements below, basically branching off like the limbs of a tree 

ftw = true 
wtf = false 

if (ftw == true) then 
   if (wtf == true) then 
      print ("FTW? WTF!") 
   else -- wtf will be false 
      print ("FTW!") 
   end -- THE ALMIGHTY END 
else --ftw will be false 
   if (wtf == true) then 
      print ("WTF?!") 
   else -- wtf will be false 
      print ("I am so confused...") 
   end -- THE ALMIGHTY END 
end -- THE ALMIGHTY END 

-- As you can see, we needed multiple ends for the multiple if statements. Having a loop or IF block inside another is called nesting. 


 
--[[ 6.lua 

LOOPS! YAY! ]] 

-- While loop 

count = 0 -- Initialize the counter variable 

while (count <= 5) do -- Okay, this is self explanatory but I'll explin anyway. While count is less than or equal to five. do... 
   print (count) -- this, and print what count is and... 
   count = count + 1 -- advance the loop, adding one to count. 
end -- %%%%%%%%%%%%%%% THIS IS AN IMPORTANT PART OF ANY CONTROL STRUCTURE. DONT FORGET END! 

print ("#") 

-- Repeat loop 

repeat -- Repeat doing... 
   print (count) -- print the count... 
   count = count - 1 -- and subtract one from count total... 
until (count <= 0) -- Until count is less than or equal to 0. 

print ("#") 

-- For loop 

for i = 1,3 do -- Initialize i as equal to 1. Then set the condition for the loop to end as 3. So when i = 3, the loop ends. Thus, i = 1,3. Then do.. 
   print(i) -- print i 
end -- %%%%%%%%%%%%%%% THIS IS AN IMPORTANT PART OF ANY CONTROL STRUCTURE. DONT FORGET END! 


 
--[[ 7.lua 

Functions and some basic Object Oriented programming ]] 

-- This program calculates the final value of a number, give the base and the exponent 

function exponent (base, power) -- We define it as a function and give it a name we'll use later. Then we put two place holder variables 
temp = 1 -- Initializes temp as 1, because anything raised to 0 is 1. 
   repeat -- Start a loop 
      temp = base * temp -- Multiply the base number by itself (or by one if just starting) 
      power = power - 1 -- And decrease the power counter 
   until (power <= 0) -- Until there is nothing left to calculate 
    
   print (temp) 
end 

print ("Please enter a base number: ") 
user_base = io.read ()-- io.read() is the command one uses to grab input from the user 
-- user_base = tonumber (io.read ()) is another way of doing it, if you would like to make sure the program sees the input as a number 

print ("Please enter the exponent to raise the base number to: ") 
user_power = io.read () 

user_base = tonumber (user_base) -- Again. tonumber ( something) makes sure that the something converts to a number 
user_power = tonumber (user_power) 

print ("Result is: ") 
exponent (user_base, user_power)--[[We use the function like a cookie cutter now. Throw in our own variables 
and run through the same set of commands held by one function. This is an object oriented programming principle, reusability ]] 


 
--[[ 8.lua 

The Math Library ]] 

-- This program will introduce some fundamental math functions one would use in most scripts 

-- math.abs : The absolute alue function. This takes any number and strips it to it's base. So negatives become positives 

x = 1 -- x as a positive number 
print ("x = " .. x) 

x = -1 -- x as a negative number 
print ("x = " .. x) 

x = math.abs (x) -- x as its absolute value 
print ("The absolute value of x = " .. x) 

print ("") 

-- math.ceil : The Round Up function. This takes any number and rounds it up to the next largest integer 

x = 2.4 
print ("x = " .. x) 

x = math.ceil (x) 
print ("x rounded up is " .. x) 

print ("") 

-- math.floor : The Round Down function. This takes any number and rounds it down to the next smallest integer 

x = 2.4 
print ("x = " .. x) 

x = math.floor (x) 
print ("x rounded down is " .. x) 

print ("") 

-- math.max : The Find Max Number function. This finds the largest number of a group of given numbers 

print ("The largest number of 2, 41, -3 and 3.4 is " .. math.max (2, 41, -3, 3.4)) 

-- math.min : The Find Min Number function. This finds the smallest number of a group of given numbers 

print ("The smallest number of 2, 41, -3 and 3.4 is " .. math.min (2, 41, -3, 3.4)) 

print ("") 

-- math.pow : The Exponent function. This finds the numeric value of an exponential expression, given the base number and the power 

x = 2 
y = 4 
z = math.pow (x, y) -- Is the normal way of writing the command. It is x raised y number of times 
a = math.pow (x^y) -- Is another way of writing the command 

print ("x = " .. x .. ", y = " .. y .. ", and math.pow (x, y) = " .. z) 
print ("math.pow (x^y) also is equal to " .. a) 

print ("") 

-- math.sqrt : The Squre Root function. This finds the squre root of the given variable 

x = 9 
print (" The squre root of " .. x .. " = " .. math.sqrt (x)) 

-- math.random : The Random Number Picker function! This is what you'd use to make a gambling game :P More explained below 

x = math.random () -- When called with no argument (ie, nothing in the parantheses), it returns a number between 0 and 1 
print (x) 

x = math.random (10) -- When called with one argument, it returns a number between 1 (assumed by Lua) and the number in the parentheses 
print (x) 

x = math.random (4, 8) -- When called with two arguments, it returns a number between both the numbers inputted 
print (x)

[Viter]

what editor do i need to make LUA scripts?

[[Shon3m]]

Microsoft Visual Studio .NET 2003 >.<

[The Kingofbeast]

That or notepad XD

[Viter]

/target Viter
/slap
/yell DOH!

Microsoft Visual Studio .NET 2003 >.<

Ore maybe 2008?

[Cursed]

Only your notepad :P

[[Shon3m]]

rolfz that works as well lol

[latruwski]

what editor do i need to make LUA scripts?

you can make lua scripts in notepad ^^ just save it as .lua instead of .txt


grtz