1. language Find the latest version of this document at http://touchdevelop.com/slides.http://touchdevelop.com/slides

2. Numbers o Numbers represent any integral or fractional number. 1, 1.5, -10 o All the usual arithmetic operators are available. 1 + 2, 3 / 2.5, 10 < 20, 5 = 5 o More math goodness in math math->sin(3.2)

3. Text o A piece of text is called a String. "Hello" o You can glue strings together using || "Hello " || "world" o You can access the number of characters ( count ) and each character individually ( at ). "Hello"->count 5 "Hello"->at(0) H

4. local variables o a local variable holds a value in memory; a local variable can be read or written too. definition var x := 0 reading x->post to wall update with new value x := 5

5. while loops o while loop: repeats the same code while the condition holds definition while... do... true or false happens when true

6. for loops o for loop: repeats the same code multiple times definition for 0 ≤ index < count do... index starts at 0, increments by 1 on each iteration and finishes at count-1. index goes through 0, 1, 2, …, count-1

7. for each loops o for each loop: repeats the same code for each element of a collection definition for each song in media->songs do... song goes through every song in songs

8. Boolean values o a Boolean value may be true or false definition var b := true var c := false

9. if statement: executes different code based on a Boolean condition if... then... else... if.. then.. else.. true or false happens when true happens when false

10. actions functions: a collection of lines of code with a name that one can call. Functions can have inputs and outputs. action square(x : Number) returns r : Number r := x * x x is an input, it is a number r is an output, it is a number the action is called ‘square’ storing x*x into r

11. ‘not’ operator o examples not truefalse true not true = false not false = true not (not true) = true

12. ‘or’ operator o examples true or false = true false or true = true false or false = false or truefalse true falsetruefalse

13. ‘and’ operator o examples true and false = false false and true = false true and true = true and truefalse true false

14. arithmetic operators o compares 2 numbers and returns a Boolean value x < y = true if x is less than y ; otherwise x < y = false. x ≤ y = true if x is less or equal than y ; otherwise x ≤ y = false.

15. global variables o a global variable is variables available in all actions and events; a global variable can be read or written to. global variables are stored under data. In the editor, data-> is shortened to the square symbol. reading data->x->post to wall update with new value data->x := 5

16. o the scope of a local variable is the area of code where this local variable exists; the scope is the outermost block of code. action go() var x := 0 for 0 ≤ index < count do var y : = 0 scope scope of x scope of y

17. while vs for o a for loop can be written as a while loop for: while: var index := 0 while index < 10 do index->post to wall index := index + 1 for 0 ≤ index post to wall