All basics

README.md

@@ -1,3 +1,171 @@
 # cheat-sheet-lua
 
-Here is the IO-Project cheat sheet to quickly learn the "Lua" programming language
+Here is the IO-Project cheat sheet to quickly learn the "Lua" programming language
+
+## Table of contents
+
+Use this table of contents to travel more easily through this cheat sheet.
+
+- [cheat-sheet-lua](#cheat-sheet-lua)
+  - [Table of contents](#table-of-contents)
+  - [The basics](#the-basics)
+    - [Code comments](#code-comments)
+    - [Variables and flow control](#variables-and-flow-control)
+    - [Functions](#functions)
+  - [Advanced](#advanced)
+    - [Tables/array](#tablesarray)
+      - [Metatables and metamethods](#metatables-and-metamethods)
+      - [](#)
+
+## The basics
+
+### Code comments
+
+````lua
+-- Two dashes start a one-line comment.
+
+--[[
+     by adding two "[" opening and two "]" closing,
+     you define a multi-line commentary. ;-)
+--]]
+````
+
+### Variables and flow control
+
+Introduction to variables, basic conditions, some loops ([examples available here](support/while.lua)) and the equivalent of the ternary operator.
+
+````lua
+num = 42  -- All numbers are doubles.
+-- Don't freak out, 64-bit doubles have 52 bits for
+-- storing exact int values; machine precision is
+-- not a problem for ints that need < 52 bits.
+
+s = 'walternate'  -- Immutable strings like in Python.
+t = "double-quotes are also fine"
+u = [[ Double brackets
+       start and end
+       multi-line strings]]
+t = nil  -- Undefines t; Lua has garbage collection.
+
+-- Blocks are denoted with keywords like do/end:
+while num < 50 do
+  num = num + 1  -- No ++ or += type operators.
+end
+
+-- If clauses:
+if num > 40 then
+  print('over 40')
+elseif s ~= 'walternate' then  -- ~= is not equals.
+  -- Equality check is ==; ok for strs.
+  io.write('not over 40\n')  -- Defaults to stdout.
+else
+  -- Variables are global by default.
+  thisIsGlobal = 5  -- Camel case is common.
+
+  -- How to make a variable local:
+  local line = io.read()  -- Reads next stdin line.
+
+  -- String concatenation uses the .. operator:
+  print('Winter is coming, ' .. line)
+end
+
+-- Undefined variables return nil.
+-- This is not an error:
+foo = anUnknownVariable  -- Now foo = nil.
+
+aBoolValue = false
+
+-- Only nil and false are false; 0 and '' are true.
+if not aBoolValue then print('that was false') end
+
+-- 'or' and 'and' are short-circuited.
+-- This is similar to the a?b:c operator in C/js:
+ans = aBoolValue and 'yes' or 'no'  --> 'no'
+
+karlSum = 0
+for i = 1, 100 do  -- The range includes both ends.
+  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
+
+-- In general, the range is begin, end[, step].
+
+-- Another loop construct:
+repeat
+  print('the way of the future')
+  num = num - 1
+until num == 0
+````
+
+### Functions
+
+Abordons la définition de fonctions plus complètes, la récurcivité, les closures. Découverte de l'asignation d'une suite de valeur a une suite de variable. 
+
+````lua
+-- The famous Fibonacci sequence.
+function fib(n)
+  if n < 2 then return 1 end
+  return fib(n - 2) + fib(n - 1)
+end
+
+-- Closures and anonymous functions are ok:
+function adder(x)
+  -- The returned function is created when adder is
+  -- called, and remembers the value of x:
+  return function (y) return x + y end
+end
+a1 = adder(9)
+a2 = adder(36)
+print(a1(16))  --> 25
+print(a2(64))  --> 100
+
+-- Returns, func calls, and assignments all work
+-- with lists that may be mismatched in length.
+-- Unmatched receivers are nil;
+-- unmatched senders are discarded.
+
+x, y, z = 1, 2, 3, 4
+-- Now x = 1, y = 2, z = 3, and 4 is thrown away.
+
+function bar(a, b, c)
+  print(a, b, c)
+  return 4, 8, 15, 16, 23, 42
+end
+
+x, y = bar('zaphod')  --> prints "zaphod nil nil"
+-- Now x = 4, y = 8, values 15..42 are discarded.
+
+-- Functions are first-class, may be local/global.
+-- (global) These are the same:
+function f(x) return x * x end
+f = function (x) return x * x end -- same of javascript definition
+
+-- (local) And so are these:
+local function g(x) return math.sin(x) end
+local g; g = function (x) return math.sin(x) end
+-- the 'local g' decl makes g-self-references ok.
+
+-- Trig funcs work in radians, by the way.
+
+-- Calls with one string param don't need parens:
+print 'hello'  -- Works fine.
+````
+
+## Advanced
+
+### Tables/array
+
+````
+
+````
+
+#### Metatables and metamethods
+
+````
+
+````
+
+#### 

support/while.lua

@@ -0,0 +1,41 @@
+-- Jeb while loop
+local jebSum = 0
+print('jeb : '..jebSum)
+while jebSum < 10 do
+  jebSum = jebSum + 1
+  print('jeb : '..jebSum)
+end
+print('\n')
+
+-- Rob for loop
+for i = 1, 10 do
+  print('Rob : '..i)
+end
+print('\n')
+
+-- Tim for loop
+for i = 0, 20, 2 do
+  print('Tim : '..i)
+end
+print('\n')
+
+-- Clara for loop
+for k,v in pairs({'hi', 'hello', 'smart', 'and', 'or', 'if', 'add', 'die', 'negatif', 'positive'}) do
+  print('Clara : '..k..' '..v)
+end
+print('\n')
+
+-- Mart while loop
+local martSum = 0
+repeat
+  print('Mart : '..martSum)
+  martSum = martSum + 1
+until martSum > 10
+print('\n')
+
+-- Breaking out loop
+while true do
+  print('Breaking out in')
+  if true then break end
+end
+print('Breaking out -> Done')