The Ring programming language version 1.10 book - Part 39 of 212
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The document discusses object-oriented programming in Ring. It explains that classes can be defined to create objects, and objects can access attributes and methods using braces or dot notation. Constructors can be used to initialize objects. Inheritance, packages, sorting and finding objects are also covered.
![CHAPTER
FORTYFIVE
OBJECT ORIENTED PROGRAMMING (OOP)
In this chapter we are going to learn how to use the Object-Oriented programming paradigm inside the Ring program-
ming language.
We will learn about
• Classes and Objects
• Access Objects Using Braces
• Composition
• Setter and Getter
• Private Attributes and Methods
• Operator Overloading
• Inheritance
• Dynamic Attributes
• Packages
• Printing Objects
• Find() and List of Objects
• Sort() and List of Objects
• Using Self.Attribute and Self.Method()
• Using This.Attribute and This.Method()
45.1 Classes and Objects
We can define new classes using the next syntax
Syntax:
Class <Class Name> [From|<|: <Parent Class Name>]
[Attributes]
[Methods]
[Private
[Attributes]
[Methods]
]
354](https://image.slidesharecdn.com/381ring-190427182055/85/The-Ring-programming-language-version-1-10-book-Part-39-of-212-7-320.jpg)
![Ring Documentation, Release 1.10
And we can create objects using the next syntax
Syntax:
New <Object Name> [ (init method parameters) ] |
[ { access object data and methods } ] ---> Object
Example:
New point { x=10 y=20 z=30 print() }
Class Point x y z func print see x + nl + y + nl + z + nl
Note: We can use { } to access object data and methods.
Tip: we can declare the class attributes directly after the class name.
Output:
10
20
30
We can rewrite the same program in another style
New point # create new object using the point class
{ # access the new object attributes and methods
x = 10 # set the x attribute to 10
y = 20 # set the y attribute to 20
z = 30 # set the z attribute to 30
print() # call the print method
} # end of object access
Class Point # define the Point class
x y z # the class contains three attributes x, y & z
func print # define the print method
see x + nl + # print the x attribute
y + nl + # print the y attribute
z + nl # print the z attribute
Also we can write the same program in another way
P1 = New Point
P1.x = 10
P1.y = 20
P1.z = 30
P1.Print()
Class Point x y z func print see x + nl + y + nl + z + nl
Note: we can use the dot operator after the object name to access object members.
Also we can write the same program in another way
new point { print() }
Class Point
x = 10 y = 20 z = 30
func print see x + nl + y + nl + z + nl
45.1. Classes and Objects 355](https://image.slidesharecdn.com/381ring-190427182055/85/The-Ring-programming-language-version-1-10-book-Part-39-of-212-8-320.jpg)
![Ring Documentation, Release 1.10
Note: we can set the default values for the class attributes when we declare them.
Also we can write the same program in another way
new point(10,20,30)
Class Point
x y z
func init p1,p2,p3 x=p1 y=p2 z=p3 print()
func print see x + nl + y + nl + z + nl
Note: we can call the init method directly using () when we create new objects
Also we can write the same program in another way
new point( [ :x = 10 , :y = 20 , :z = 30 ] )
Class Point x y z
func init aPara x = aPara[:x] y = aPara[:y] z = aPara[:z] print()
func print see x + nl + y + nl + z + nl
Tip: using Hash for passing method parameters enable us to create optional parameters and change the order of
parameters when adding them to the Hash.
45.2 Access Objects Using Braces
We can access the object at any time using braces { }
Inside the braces we can use the object attributes and methods directly
This can be done when we create the object using the New keyword or at any time using the next syntax
ObjectName { access object data and methods }
Example:
See "Creating the Object" + nl
o1 = new Point
See "Using the Object" + nl
o1 {
x=5
y=15
z=25
print()
}
Class Point x y z func print see x + nl + y + nl + z
We can use braces to access objects when we call functions or methods
Example:
o1 = new Point
print( o1 { x=10 y=20 z=30 } )
func print object
see object.x + nl +
object.y + nl +
45.2. Access Objects Using Braces 356](https://image.slidesharecdn.com/381ring-190427182055/85/The-Ring-programming-language-version-1-10-book-Part-39-of-212-9-320.jpg)
The Ring programming language version 1.10 book - Part 39 of 212
- 1. CHAPTER FORTYFOUR SECURITY AND INTERNET FUNCTIONS This chapter contains the security and internet functions provided by the Ring programming language for Hashing, Encryption & Decryption. Before using the next function load the openssllib.ring library load "openssllib.ring" # Use OpenSSL functions • MD5() • SHA1() • SHA256() • SHA512() • SHA384() • SHA224() • Encrypt() • Decrypt() • Randbytes() Before using the next function load the internetlib.ring library load "internetlib.ring" # Use the Internet functions • Download() • SendEmail() 44.1 MD5() Function We can calculate the MD5 hash using the MD5() Function Syntax: MD5(cString) ---> String contains the MD5 hash of the string cString Example: see "md5('happy') = " + md5("happy") + nl + "md5('Hello') = " + md5("Hello") + nl 348
- 2. Ring Documentation, Release 1.10 Output: md5('happy') = 56ab24c15b72a457069c5ea42fcfc640 md5('Hello') = 8b1a9953c4611296a827abf8c47804d7 44.2 SHA1() Function We can calculate the SHA1 hash using the SHA1() Function Syntax: SHA1(cString) ---> String contains the SHA1 hash of the string cString Example: see "sha1('hello') : " + sha1("hello") + nl + "sha1('apple') : " + sha1("apple") + nl Output: sha1('hello') : aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d sha1('apple') : d0be2dc421be4fcd0172e5afceea3970e2f3d940 44.3 SHA256() Function We can calculate the SHA256 hash using the SHA256() Function Syntax: SHA256(cString) ---> String contains the SHA256 hash of the string cString Example: see "sha256('hello') : " + sha256("hello") + nl + "sha256('apple') : " + sha256("apple") + nl Output: sha256('hello') : 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 sha256('apple') : 3a7bd3e2360a3d29eea436fcfb7e44c735d117c42d1c1835420b6b9942dd4f1b 44.4 SHA512() Function We can calculate the SHA512 hash using the SHA512() Function Syntax: SHA512(cString) ---> String contains the SHA512 hash of the string cString Example: see "sha512('hello') : " + sha512("hello") + nl + "sha512('apple') : " + sha512("apple") + nl + "sha512('hello world') : " + sha512("hello world") + nl 44.2. SHA1() Function 349
- 3. Ring Documentation, Release 1.10 Output: sha512('hello') : 9b71d224bd62f3785d96d46ad3ea3d73319bfbc2890caadae2dff72519673c a72323c3d99ba5c11d7c7acc6e14b8c5da0c4663475c2e5c3adef46f73bcdec043 sha512('apple') : 844d8779103b94c18f4aa4cc0c3b4474058580a991fba85d3ca698a0bc9e52 c5940feb7a65a3a290e17e6b23ee943ecc4f73e7490327245b4fe5d5efb590feb2 sha512('hello world') : 309ecc489c12d6eb4cc40f50c902f2b4d0ed77ee511a7c7a9bcd3ca8 6d4cd86f989dd35bc5ff499670da34255b45b0cfd830e81f605dcf7dc5542e93ae9cd76f 44.5 SHA384() Function We can calculate the SHA384 hash using the SHA384() Function Syntax: SHA384(cString) ---> String contains the SHA384 hash of the string cString Example: see "sha384('hello') : " + sha384("hello") + nl + "sha384('apple') : " + sha384("apple") + nl + "sha384('hello world') : " + sha384("hello world") + nl Output: sha384('hello') : 59e1748777448c69de6b800d7a33bbfb9ff1b463e44354c3553bcdb9c666fa 90125a3c79f90397bdf5f6a13de828684f sha384('apple') : 3d8786fcb588c93348756c6429717dc6c374a14f7029362281a3b21dc10250 ddf0d0578052749822eb08bc0dc1e68b0f sha384('hello world') : fdbd8e75a67f29f701a4e040385e2e23986303ea10239211af907fcb b83578b3e417cb71ce646efd0819dd8c088de1bd 44.6 SHA224() Function We can calculate the SHA224 hash using the SHA224() Function Syntax: SHA224(cString) ---> String contains the SHA224 hash of the string cString Example: see "sha224('hello') : " + sha224("hello") + nl + "sha224('apple') : " + sha224("apple") + nl + "sha224('hello world') : " + sha224("hello world") + nl Output: sha224('hello') : ea09ae9cc6768c50fcee903ed054556e5bfc8347907f12598aa24193 sha224('apple') : b7bbfdf1a1012999b3c466fdeb906a629caa5e3e022428d1eb702281 sha224('hello world') : 2f05477fc24bb4faefd86517156dafdecec45b8ad3cf2522a563582b 44.7 Encrypt() Function We can use the Encrypt() function to encrypts the data using the Blowfish algorithm. 44.5. SHA384() Function 350
- 4. Ring Documentation, Release 1.10 Syntax: Encrypt(cString, cKey, cIV) ---> Encrypted string 44.8 Decrypt() Function We can use the Decrypt() function to decrypt the data encrypted using the Encrypt() function. Syntax: Decrypt(cCipher, cKey, cIV) ---> Decrypted string 44.9 Encryption and Decryption Example The next example demonstrates how to use the Encrypt() and Decrypt() functions. These functions use the Blowfish algorithm. See "Enter a string : " give cStr list = 0:15 cKey="" for x in list cKey += char(x) next list = 1:8 cIV = "" for x in list cIV += char(x) next cStr = Encrypt(cStr,cKey,cIV) See "Cipher Text : " + cStr + nl + "Plain Text : " + Decrypt(cStr,cKey,cIV) + nl We can write the same example using normal for loop See "Enter a string : " give cStr cKey="" # 16 bytes for x = 0 to 15 cKey += char(x) next cIV = "" for x = 1 to 8 cIV += char(x) next cStr = Encrypt(cStr,cKey,cIV) See "Cipher Text : " + cStr + nl + "Plain Text : " + Decrypt(cStr,cKey,cIV) + nl Also we can write the password and the IV directly using strings See "Enter a string : " give cStr # Note: Don't use simple password in real applications! cKey = "1234567890@#$%^&" cIV = "87654321" cStr = Encrypt(cStr,cKey,cIV) See "Cipher Text : " + cStr + nl + "Plain Text : " + Decrypt(cStr,cKey,cIV) + nl 44.8. Decrypt() Function 351
- 5. Ring Documentation, Release 1.10 44.10 File Hash The next example demonstrates how to calculate the hash functions for files cStr = read("myapp.exe") see "Size : " + len(cStr) + nl + "md5 : " + md5(cStr) + nl + "sha1 : " + sha1(cStr) + nl + "sha256 : " + sha256(cStr) + nl + "sha224 : " + sha224(cStr) + nl + "sha384 : " + sha384(cStr) + nl + "sha512 : " + sha512(cStr) + nl Output: Size : 58079876 md5 : 762eee15d8d2fd73b71ea52538b28667 sha1 : 9212c0c7258bad89a62bd239e1358a9276a9d070 sha256 : 7d6724e69b6c553da749ba31b6185dddc965129b64d9e9bf3de88f67df3b1cdc sha224 : 5a9c8a7d662bce4f880ba94f90a79362b672528b9efd5abc718c7a3d sha384 : 18e23f973abedbeb3981c423f12aeadecf96f9c6fb28aeabe3be4c484f8540afcc3861b b370ce2b59cf3c99c130b856b sha512 : da3d5e997d06f8b2a7a9964b77f7d82eedb76b245c611082c1639f83f51d83880bcd08f cd53dcab1167bdca0b82fec5071971ac17c76479d76985ced4ab0d18e 44.11 Randbytes() Function We can generate a string of pseudo-random bytes using the Randbytes() function. Syntax: Randbytes(nSize) ---> String contains random bytes (bytes count = nSize) Example: salt = randbytes(32) password = "SecretPassWord@$%123" see salt + nl see sha256("test" + salt) + nl 44.12 Download() Function Syntax: Download(cURL) ---> String contains the server response Example: cStr= download("http://doublesvsoop.sourceforge.net/") see cStr write("download.txt",cStr) 44.10. File Hash 352
- 6. Ring Documentation, Release 1.10 44.13 SendEmail() Function Syntax: SendEmail(cSMTPServer,cEmail,cPassword,cSender,cReceiver,cCC,cTitle,cContent) Example: See "Send email..." + nl sendemail("smtp://smtp.gmail.com:587", "[email protected]", "password", "[email protected]", "[email protected]", "[email protected]", "Sending email from Ring", "Hello How are you? Are you fine? Thank you! Greetings, Mahmoud") see "Done.." + nl 44.13. SendEmail() Function 353
- 7. CHAPTER FORTYFIVE OBJECT ORIENTED PROGRAMMING (OOP) In this chapter we are going to learn how to use the Object-Oriented programming paradigm inside the Ring program- ming language. We will learn about • Classes and Objects • Access Objects Using Braces • Composition • Setter and Getter • Private Attributes and Methods • Operator Overloading • Inheritance • Dynamic Attributes • Packages • Printing Objects • Find() and List of Objects • Sort() and List of Objects • Using Self.Attribute and Self.Method() • Using This.Attribute and This.Method() 45.1 Classes and Objects We can define new classes using the next syntax Syntax: Class <Class Name> [From|<|: <Parent Class Name>] [Attributes] [Methods] [Private [Attributes] [Methods] ] 354
- 8. Ring Documentation, Release 1.10 And we can create objects using the next syntax Syntax: New <Object Name> [ (init method parameters) ] | [ { access object data and methods } ] ---> Object Example: New point { x=10 y=20 z=30 print() } Class Point x y z func print see x + nl + y + nl + z + nl Note: We can use { } to access object data and methods. Tip: we can declare the class attributes directly after the class name. Output: 10 20 30 We can rewrite the same program in another style New point # create new object using the point class { # access the new object attributes and methods x = 10 # set the x attribute to 10 y = 20 # set the y attribute to 20 z = 30 # set the z attribute to 30 print() # call the print method } # end of object access Class Point # define the Point class x y z # the class contains three attributes x, y & z func print # define the print method see x + nl + # print the x attribute y + nl + # print the y attribute z + nl # print the z attribute Also we can write the same program in another way P1 = New Point P1.x = 10 P1.y = 20 P1.z = 30 P1.Print() Class Point x y z func print see x + nl + y + nl + z + nl Note: we can use the dot operator after the object name to access object members. Also we can write the same program in another way new point { print() } Class Point x = 10 y = 20 z = 30 func print see x + nl + y + nl + z + nl 45.1. Classes and Objects 355
- 9. Ring Documentation, Release 1.10 Note: we can set the default values for the class attributes when we declare them. Also we can write the same program in another way new point(10,20,30) Class Point x y z func init p1,p2,p3 x=p1 y=p2 z=p3 print() func print see x + nl + y + nl + z + nl Note: we can call the init method directly using () when we create new objects Also we can write the same program in another way new point( [ :x = 10 , :y = 20 , :z = 30 ] ) Class Point x y z func init aPara x = aPara[:x] y = aPara[:y] z = aPara[:z] print() func print see x + nl + y + nl + z + nl Tip: using Hash for passing method parameters enable us to create optional parameters and change the order of parameters when adding them to the Hash. 45.2 Access Objects Using Braces We can access the object at any time using braces { } Inside the braces we can use the object attributes and methods directly This can be done when we create the object using the New keyword or at any time using the next syntax ObjectName { access object data and methods } Example: See "Creating the Object" + nl o1 = new Point See "Using the Object" + nl o1 { x=5 y=15 z=25 print() } Class Point x y z func print see x + nl + y + nl + z We can use braces to access objects when we call functions or methods Example: o1 = new Point print( o1 { x=10 y=20 z=30 } ) func print object see object.x + nl + object.y + nl + 45.2. Access Objects Using Braces 356
- 10. Ring Documentation, Release 1.10 object.z Class Point x y z We can mix between using braces and the dot operator to access the object in the same expression. Example: o1 = new Point O1 { x=10 y=20 z=30 }.print() Class Point x y z func print see x + nl + y + nl + z 45.3 Composition The object may contains other objects as attributes. Using braces to access objects can be nested. Example: R1 = New Rectangle { Name = "Rectangle 1" P1 { X = 10 Y = 20 } P2 { X = 200 Y = 300 } Color = "Blue" } see "Name : " + R1.Name + nl + "Color: " + R1.Color + nl + "P1 : (" + R1.P1.X + "," + R1.P1.Y + ")" + nl + "P2 : (" + R1.P2.X + "," + R1.P2.Y + ")" Class Rectangle name color p1 = new Point p2 = new Point Class Point x y Output: 45.3. Composition 357