View source for KTurtle/C2/Grammar-of-TurtleScript/English

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!Visual Cue
!Narration
|-
||'''Slide Number 1'''

'''Title slide'''
||Hello everybody.

Welcome to this tutorial on '''Grammar of TurtleScript''' in '''KTurtle'''. 
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||'''Slide Number 2''' 

'''Learning Objectives''' 
||In this tutorial, we will learn 

* Grammar of Turtle script  and

* 'if'-'else' condition
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||'''Slide Number 3''' 

'''System Requirement''' 
||To record this tutorial I am using, 

Ubuntu Linux OS version. 12.04. 

KTurtle version. 0.8.1 beta. 
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||Slide Number 4 

'''Pre-requisites''' 
||We assume that you have basic working knowledge of KTurtle 

If not, 

for relevant tutorials, please visit our website. 

'''http://spoken-tutorial.org''' 
|-
||Switch to '''KTurtle''' Application 

'''Dash home''' >>In the Search bar

type '''KTurtle''' click on the '''KTurtle''' icon. 
||Let's open a new '''KTurtle''' Application. 

Click on '''Dash home'''.  

In the Search bar, type '''KTurtle.''' 

Click on the '''KTurtle''' icon. 
|-
||Press '''CTRL+ALT+T'''  >> open the '''Terminal''' 

>>type kTurtle >>press enter to open
||We  can also open  KTurtle Application from the '''Terminal.'''

Press '''CTRL+ALT+T''' simultaneously to open the '''Terminal'''.
 
Type '''KTurtle'''  and press enter  '''KTurtle'''. Application opens
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||Slide Number 5

Turtle Script
||First I will explain about '''TurtleScript'''

* '''TurtleScript''' is a programming language 

* It has different types of '''words and symbols''' used for '''various purposes''' 

* It '''instructs''' Turtle what to do
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||'''Slide Number 6'''

'''Grammar of TurtleScript'''
||'''Grammar of TurtleScript''' in''' KTurtle''' includes- 

* Comments

* Commands

* Numbers

* Strings

* Variables and

* Boolean values
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||'''Slide Number 7'''

'''Numbers'''
||Now we will see where to store numbers

'''Numbers'''  can be stored in

* Mathematical operators

* Comparison operators and

* Variables
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||'''Zoom text'''
||I will zoom the program text for clear view.
|-
||'''Switch to KTurtle window'''
||First  let's look at variables. 

Variables are words that start with a ‘$’, for example $a.

In the editor they are highlighted with '''purple'''. 

Using the assignment, equal to (=), a variable is given its content. 

Variables can contain  numbers '''$a=100'''.

strings '''$a=hello''' or 

boolean  values that is true or false '''$a=true'''

Variable keeps the content until program finishes  execution or until it is reassigned to something else. 

You can use variables, once assigned, just as if they are their content. 
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||
||For example, consider the code typed in the editor.

'''$a = 2004''' 

'''$b = 25''' 

'''print $a + $b''' 
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||
||Variable 'a' is assigned a  value ''' 2004.'''

Variable 'b' is assigned a value '''25''' 

'''print''' command commands Turtle to write something on the canvas. 

'''print'''  command takes numbers and strings as input. 

'''print $a + $b'''  commands '''Turtle''' to add two values and display them on the canvas.
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||Run the code
||Let's Run the code '''slow''' speed.

Value '''2029''' is displayed on the canvas
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||'''Slide Number 8'''

'''Mathematical operators'''
||Let us next see the Mathematical  Operators.

Mathematical operators include,

* '''+''' (Addition) 

* '''-''' (Subtraction) 

* '''*''' (Multiplcation) 

* '''/''' (Division)
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||
||I already have a program in a text editor. 
|-
||
'''reset'''

'''canvassize 200,200''' 

'''$add = 1 + 1'''

'''$subtract = 20 – 5'''

'''$multiply = 15 * 2'''

'''$divide = 30 /30'''

'''go 10,10'''

'''print $add'''

'''go 50,50'''

'''print $subtract'''

'''go 100,100
'''
'''print $multiply'''

'''go 175,175'''

'''print $divide'''

'''go 0,0'''
||I will copy the code from text editor and paste it into '''KTurtle''' editor.

Pause the tutorial and type the program into''' KTurtle''' editor.

Resume the tutorial after typing the program
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||
||I will Explain the code now
|-
||Highlight''' reset'''
||'''“reset”''' command sets Turtle to its '''default''' position
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||Highlight '''canvassize 200,200''' 

||'''canvassize 200,200''' fix the width and height of the canvas to 200 pixels each. 
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||Highlight '''$add = 1 + 1'''
|| value '''1+1''' is assigned to the variable''' $add,''' 
|-
||Highlight''' $subtract = 20 – 5'''
||Value '''20-5''' is assigned to variable '''$subtract''', 
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||Highlight''' $multiply = 15 * 2'''
||value '''15 * 2''' is be assigned to the variable '''$multiply.''' 
|-
||Highlight $divide = 30 /30
||'''30/30''' is assigned to the variable '''$divide.''' 
|-
||Highlight '''go 10,10'''
||'''go 10,10''' commands to '''Turtle''' to go 10 pixels left of canvas and 10 pixels from top of canvas
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||Run code

Point to the values
||Let us now run this code in  slow speed

Command which is getting executed is highlighted in the editor.

'''Turtle''' displays the values on the canvas at the specified positions. 
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||
||Let us consider a simple example for using the '''comparison operator''' .

Type the commands being shown on the screen.
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|| zoom  text
||I will  zoom the text to have clear view
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||Switch to Kturtle Window
||'''$answer = 10 > 3'''

'''print $answer'''

Here 10 is compared to 3 with the ’'''greater than'''’ operator.

The result of this comparison, the '''boolean value true''' is stored in the 

variable '''$answer''' and the value '''true''' is displayed.
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||Run the code
||Let's run this code 

'''Turtle''' has displayed '''Boolean value true''' on the canvas.
|-
||'''Slide Number 9'''

'''Strings'''
||Now lets see how Strings work in this application –

* Strings can be put in variables like numbers 

* Strings cannot be used in mathematical or comparison operators 

* Strings are highlighted in red color 

*KTurtle identifies a line in double quote as a string
|-
||clear code
||I will clear the current code from editor.
|-
||Example of string
||For example:I am typing the print command followed by a string, 

'''“Hello”'''. 

We See that the string is highlighted in '''Red color'''. 
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||Run code
||When I run this piece of code, the turtle displays the string on the canvas. 
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||Boolean Values 
||Next  I will explain about Boolean values.

There are only two '''boolean''' values: '''true''' and '''false.''' 
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||
||For example  Let's type the code 

'''`if-else' Condition'''

'''$answer = 7<5'''

'''print $answer''' 

'''Boolean''' value '''false''' is displayed on the canvas.

'''Boolean value false''' is assigned to variable''' $answer'''  because 7 is larger than 5
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||“if-else” conditon.
||Let's next learn about “if-else” conditon.

‘if’ condition is executed only if the '''boolean''' value evaluates ‘true’ 

‘else’ condition is executed only if the ‘if’ 
condition is ‘false’ .
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||
||I already have a program in a text editor. 
|-
||'''reset'''

'''$x=4'''

'''if $x>5 {'''

'''print $x'''

'''print “is greater than five”'''

'''}'''

'''else {'''

'''print $x''' 

'''print “is smaller than six”'''

}

'''go 0,0'''
|| I will copy the code from text editor and paste it into '''KTurtle''' editor.

Pause the tutorial and type the program into '''KTurtle''' editor.

Resume the tutorial after typing the program
|-
||
||This code compares  numbers 4 , 5 and 6 and  displays the results accordingly. 
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||Run code
||Let me now run this code. 

'''Turtle''' has compared the variables 4 and 5.

and displayed the  result 4 is smaller than 6 on the canvas . 
|-
||
||With this we come to the end of this tutorial.

Let's summarize.
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||'''Slide Number 10'''
'''Summary'''
||In this tutorial,  we have learnt about 

* Grammar of Turtle script  and

* ‘if-else’ condition 
|-
||'''Slide Number 11'''

'''Assignment'''
||Now to the assignment part.

'''Solve an equation using
'''
* if - else condition

* Mathematical  and comparision  operators

* Display the results using  “print” and “go” commands. 
|-
||'''Slide Number 12'''

'''Assignment'''
||
To solve the assignment

*Choose any four random numbers

*Multiply two sets of random numbers

*Compare the results using the comparison operators

*Display the results 

*Display greater result at center of the canvas 

*You can choose any equation which you like. 
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||'''Slide number 13''' 

'''Acknowledgement''' 
||Watch the video available at this URL

'''http://spoken-tutorial.org/What is a Spoken Tutorial'''

It summarises the Spoken Tutorial project

If you do not have good bandwidth, you can download and watch it 

|-
||'''Slide Number 14''' 
||The Spoken Tutorial Project Team : 

Conducts workshops using spoken tutorials

Gives certificates to those who pass an online test 

For more details, please write to 

'''contact@spoken-tutorial.org''' 
|-
||'''Slide number 15''' 
||Spoken Tutorial Project is a part of the Talk to a Teacher project 

It is supported by the National Mission on Education through ICT, MHRD, Government of India

More information on this Mission is available at this link

'''http://spoken-tutorial.org/NMEICT-Intro ]''' 

Script is contributed by ITfC Bangaluru.

This is Madhuri Ganpathi from IIT Bombay  signing off Thank you for joining.
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