View source for KTurtle/C2/Grammar-of-TurtleScript-Part-I/English-timed





 {| Border =1

 |'' Time''

 |'''Narration'''


 |-

 | 00.02

 |Hello Everybody. Welcome to the KTurtle tutorial




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 | 00.05

 |If this is the first time you are using KTurtle, please see the
 “Introduction to KTurtle” tutorial on the spoken tutorial website.

 |-

 |00.12

| To get started with KTurtle, I am using the Linux operating system ubuntu
 Version 11.04 and KTurtle version 0.8.1 beta.


 |-

 | 00.21

 |This tutorial will help you understand further, the '''Grammar of
 TurtleScript'''.


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 | 00.26

 | If you have already installed KTurtle,


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| 00.28

|go to the Ubuntu Menu Item '''Applications >''' '''Education''' and click
on the '''KTurtle''' Application.


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| 00.34

 |Another way to open KTurtle is by going to '''Applications > Accessories
 menu and click on Terminal'''


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 | 00.39

 | At the prompt type the name of the application that is “'''kturtle'''” and
hit 'Enter'.


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 | 00.46

 |This will open the application.


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 |00.51

 | In this tutorial, we will learn, the grammar of turtle script which
 includes,


|-

| 00.55

| commands and comments


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| 00.56

 | numbers, variables and strings


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 | 00.58

 |mathematical and comparison operators

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 | 01.00

 |and the boolean values


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 |01.02
 |And the '''if '''and '''else '''conditions


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 | 01.05

| The '''TurtleScript '''is a programming language and has different types
of words and symbols.


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 | 01.10

 |They are used for different purposes.


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 | 01.12

 |And it instructs KTurtle to do something.


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| 01.15
|The grammar of TurtleScript can include '''comments and commands, numbers
 and strings .'''


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| 01.24

|Numbers can be stored in ''mathematical operators ''in ''comparison
operators.''


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 | 01.28

 |They can also be stored in variables.


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 | 01.33

 |let us  First have a look at variables, then we look at assigning values to
 these variables.

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 |01.38

 |In the editor of  a Kturtle script ,let us open example for
 a'''variable'''.


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 |01.43

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


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 | 01.48

 |In the editor they are highlighted with the purple color.


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 | 01.52

 |Using the assignment, '''equal to a variable is given its content.


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 | 01.56

 |Variables can contain any number, string or boolean values (true/false).


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 | 02.05

 |It will keep that content until the program finishes the execution or until
 the variable is reassigned to something else.


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 | 02.11
 |You can use variables, once assigned, just as if they are their content.


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 | 02.16

 |For example, consider the code being typed in the '''editor'''  now.


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 | 02.20

|'''$a = 2004 ''''''$b = 25 '''


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 | 02.27

 |And'''print $a + $b '''


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 | 02.33
 |First the value 2004 is assigned to the variable '''$a''' .

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 | 02.37

 |The next the value 2005,25'is assigned to variable '''$b ''.




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 | 02.42

 |The '''print''' command is used to command the turtle to print something on
 the canvas.




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| 02.47

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



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 | 02.51

 |'''print $a + $b '''will add the two values and the turtle prints the value
 2024.


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 |02.57

 |I am now running the command , you can see that turtle has printed the
 final result.

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 | 03.05

 | Let us next see the Mathematical and  the Comparison Operators.


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 | 03.08

 |The basic mathematical operators here are '''+, - , * , / '''


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 | 03.16

 | In the editor of a Kturtle let us type the following example –


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 | 03.20

 |'''reset'''



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| 03.23
 |'''canvassize 200,200'''which resizes the canvas to 200 pixels of width and
 height each.



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 | 03.32

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


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 | 03.40
 |'''$subtract = 20 - 5'''


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 | 03.52

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



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 | 03.59
 |'''$divide = 30 /30'''


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 | 04.05

 |'''go 10,10'''


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 | 04.09

 |'''print $add'''

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> | 04.12

 |'''go 50,50'''



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 | 04.15

 |'''print $subtract'''



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 | 04.20

 |'''go 100,100'''



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| 04.25

 |'''print $divide'''


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 | 04.30

|'''go 0,0'''


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 |04.34

 | And'''print $multiply'''


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 | 04.41

|'''go 175,175'''



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| 04.49

 | The canvas size 200,200 fix the width and height of the canvas to 200
 pixels each.
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 |04.55

 | The value 1+1 is assigned to the variable'' $+'',

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 | 04.58

 | The 20-5 is assigned to variable subtract,

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| 05.02

 |The value 15 * 2 will be assigned to the variable ''multiply''.

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 | 05.06

 | 30/30 is assigned to the variable ''Divide.


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 | 05.10

 | We will not print the variables ,the result which is assigned to them and
 the turtle moves in the canvas.

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| 05.16

| Let us now run this code.The command which is getting executed is
highlighted in the editor and the turtle is printing the results.


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 | 05.34

 | You can see that the values have been printed on the canvas now.


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 | 05.39

 | Let us consider a simple example for using the comparison operator .Type the commands being shown on the screen


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 | 05.46

 |'''$answer = 10 > 3'''

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 | 05.51

 |And'''print $answer'''

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 | 06.02

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




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 | 06.08

 |The result of this comparison, the boolean value true will be stored in the
 variable '''$answer, '''and the value '''true '''is printed.

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| 06.15
 | Let me know Run this piece of code,you can see that the turtle has printed
 the value true on the canvas.


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| 06.24
 | lets see how Strings work in this application –


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 | 06.27
|Strings can be put in variables, just like numbers.


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 | 06.31

 |Strings cannot be used in mathematical operators or comparison operators
 and Strings are highlighted with red.

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 | 06.38

 |Strings start and end with the '''''''' mark, by these marks KTurtle knows
 that it is a string.


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 | 06.45

|For example:I am typing the print command followed by a string,See that
 the string is highlighted in Red color.


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 | 06.56

 | When I run this piece of code, the turtle prints the chain on the canvas.

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 |07.03

 | '''Boolean Values'''




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 | 07.04

 |There are only two boolean values: ''true ''and ''false''.




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 | 07.07

 |For example –I am typing the example for using the boolean value in
 kturtle.



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 | 07.14
 |'''$answer = 10 > 3'''


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 | 07.20

|'''print $answer'''

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 | 07.25

 |The turtle choose the value true,the boolean value true is assigned the
variable ''$answer ''is set to ''true ''because 10 is larger than 3.



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|07.36

 | '''Executing 'if' '''and ''''else''''conditions.


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 | 07.38

 |the code that is placed between the brackets will be executed only ''if
 ''the ''boolean value ''evaluates 'true'.


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 | 07.44

 |The code between the brackets after ''else ''is only executed if the ''if
 ''condition is false.



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| 07.50

 |For example –


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 | 07.53

 |'''reset '''



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 | 07.55

 |'''$x = 4 '''I now have a sample piece of code on my editor here , which
 compares the numbers 4 and 5 and prints the results accordingly.


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 | 08.03

 |Let me now run this code. The turtle has compared the variables 4 and 5 and
 its printing the result 4 is smaller than 6 .


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 | 08.18

 |Now to the Assignment part.




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 | 08.20

 |Using the '''if '''and '''else '''conditions, the '''mathematical
 operators''', solve an equation and print the results using the '''print
 '''and '''go '''command.

|-

 | 08.28

 |That is you can choose any four random numbers multiply the two sets of
 random numbers, compare the results using the comparison operators and print
 both the results and print that greater result at center of the canvas you
can choose any equation which you like.

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 | 08.45

 | I would like to acknowledge the spoken tutorial project
 |-

 | 08.48

 |which is part of the talk to a teacher project.


|-
|08.50

 |It is supported by the National Mission on Education through ICT, MHRD
 government of India.


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 | 08.56

 | you can see more information about this on the link shown on the screen.


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 |08.59

 | Thank you this is Sindhu signing off. Enjoy exploring KTurtle.


 |}



-- 
Thanks and regards
Madhuri Ganpathi