AbbreviatedLUAforComputerCraft

-- Two dashes start a one-line comment.

num = 42 -- All numbers are doubles.
s = "walternate" -- Immutable strings like Python.
t = nil -- Undefines t;

-- Blocks are denoted with keywords like do/end:
while num < 50 do
  num = num + 1 -- No ++ or += type operators.
end

-- An infinite loop that doesn’t end until Ctrl-R or Ctrl-T
while true do
  --do stuff over and over
end

-- If statement:
if num > 40 then
  print("over 40")
elseif s ~= "walternate" then  -- ~= is not equals.
  -- Equality check is == like Python; ok for strings.
  write("not over 40\n")  -- Another way to write out to print.
else
  -- Variables are global by default.
  thisIsGlobal = 5

  -- How to make a variable local:
  local line = read()  -- Reads next input line.

  -- String concatenation uses the .. operator:
  print("Winter is coming, "..line)

  -- Replace/Hide the input characters the user types with *
  local password = read("*")
end

-- An undefined variable return “nil”
-- This is not an error:
foo = anUnknownVariable  -- Now foo = nil.

karlSum = 0
for i = 1, 100 do  -- The range includes both ends (“1” and “100”)
  karlSum = karlSum + i
end

-- Use "100, 1, -1" as the range to count down:
fredSum = 0
for j = 100, 1, -1 do
  fredSum = fredSum + j
end
function fib(n)
if n < 2 then return 1 end
  return fib(n - 2) + fib(n - 1)
end