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languageFind the latest version of this document at http://touchdevelop.com/slides .
Numberso 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 = 5o More math goodness in math math->sin(3.2)
Texto 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
local variableso a local variable holds a value in memory;
a local variable can be read or written too.• definitionvar x := 0• reading x->post to wall• update with new valuex := 5
while loopso while loop: repeats the same code while
the condition holds• definition
while ... do...
true or false
happens when true
for loopso 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
for each loopso 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
Boolean valueso a Boolean value may be true or
false• definition
var b := true var c := false
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
actionsfunctions: 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
‘not’ operator
o examples
not true false
false
true
not true = falsenot false = truenot (not true) = true
‘or’ operator
o examplestrue or false = truefalse or true = truefalse or false = false
or true false
true true truefalse true fals
e
‘and’ operator
o examples• true and false = false• false and true = false• true and true = true
and true falsetrue true falsefalse
false
false
arithmetic operatorso 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.
global variableso 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 valuedata->x := 5
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
while vs foro a for loop can be written as a while loop
• for:
• while:var index := 0while index < 10 do index->post to wall index := index + 1
for 0 ≤ index < 11 do index->post to wall