myNum = 100                  --Number
myOtherNum = 20.18           --Number
myString = "Hello World!"    --String
myBool = true                --Boolean

-- Comment on a single line

--[[
     Block comments
     Everything in here will be
     treated as a comment
--]]

myNum = 0
myNum = myNum + 1   -- No "++" operator in Lua

--[[
     + : Addition            - : Subtraction
     * : Multiplication      / : Division
     % : Modulus Division    ^ : Exponent
--]]

if myNum == 0 then
   myNum = myNum + 1
end

--[[
     == : Equal to                  ~= : Not Equal to
     >  : Greater than              <  : Less than
     >= : Greater than or equal to  <= : Less than or equal to
--]]

if myNum > 1 then
   result = "myNum is greater than 1"
elseif myNum < 1 then
   result = "myNum is less than 1"
else
   result = "myNum is equal to 1"
end

-- While Loop
while myNum < 50 do
   myNum = myNum + 1
end

-- For Loop
-- Loops 100 times, iterator "i" increases by 1 each loop
for i=1,100 do
   myNum = myNum + 1
end

-- Optional third parameter is the increment value
-- This loop decreases by 5 each time from 100 to 0
for i=100,0,-5 do
   myNum = myNum + 1
end

function isNegative(n)
   if n < 0 then
      return true
   else
      return false
   end
end

isNegative(-15)   -- Returns true

-- Multiple parameters
function pow(base, exp) return base^exp end

-- Functions can be assigned to variables
myVar = isNegative
myVar(20)   -- Returns false

myTable = {}       -- Creates empty table
myTable[1] = 'a'   -- Put character 'a' at index 1

-- NOTE: Tables in Lua start at index 1

myTable["lua"] = 20    -- myTable contains 20 at index "lua"
myTable[1] = nil       -- Removes value stored at index 1

myTable.name = "Alex"  -- myTable["name"] contains string "Alex"

otherTable = {2, 3, 5} -- Creates table with 2 stored at index 1,
                       -- 3 stored at index 2, and 5 at index 3

-- Iterate through all values in a table
for i, n in ipairs(otherTable) do
   result = result + n
   -- i stores the current index
   -- n stores the value at current index
end
-- During loop, variable "result" increases by 2, then 3, then 5.