The Ring programming language version 1.5.3 book - Part 30 of 184
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This document provides documentation on object-oriented programming concepts in Ring, including classes, objects, inheritance, composition, private attributes/methods, operator overloading, and more. It includes examples demonstrating how to define classes, create objects, access object members, define methods for setting/getting attributes, and extend classes.
![CHAPTER
THIRTYNINE
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()
39.1 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]
]
268](https://image.slidesharecdn.com/291fayedringdoc1-180327101421/85/The-Ring-programming-language-version-1-5-3-book-Part-30-of-184-4-320.jpg)
![Ring Documentation, Release 1.5.3
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
39.1. Classes and Objects 269](https://image.slidesharecdn.com/291fayedringdoc1-180327101421/85/The-Ring-programming-language-version-1-5-3-book-Part-30-of-184-5-320.jpg)
![Ring Documentation, Release 1.5.3
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.
39.2 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 +
39.2. Access Objects Using Braces 270](https://image.slidesharecdn.com/291fayedringdoc1-180327101421/85/The-Ring-programming-language-version-1-5-3-book-Part-30-of-184-6-320.jpg)
![Ring Documentation, Release 1.5.3
Func operator cOperator,Para
...
The function operator takes two paramters, the first represent the operator and the second represent the second param-
eter after the operator.
Example:
o1 = new point { x = 10 y = 10 print("P1 : ") }
o2 = new point { x = 20 y = 40 print("P2 : ") }
o3 = o1 + o2
o3.print("P1+P2 : ")
class point x y
func operator cOperator,Para
result = new point
switch cOperator
on "+"
result.x = x + Para.x
result.y = y + Para.y
on "-"
result.x = x - Para.x
result.y = y - Para.y
off
return result
func print cPoint
see cPoint + "X : " + x + " Y : " + y + nl
Output:
P1 : X : 10 Y : 10
P2 : X : 20 Y : 40
P1+P2 : X : 30 Y : 50
39.7 Inheritance
We can create class from another class in the class definition using the keyword from.
Syntax:
Class <Class Name> [From <Parent Class Name>]
We can call a method in the parent class from the child class using the super object.
Syntax:
func methodname
...
super.methodname()
...
Example:
39.7. Inheritance 274](https://image.slidesharecdn.com/291fayedringdoc1-180327101421/85/The-Ring-programming-language-version-1-5-3-book-Part-30-of-184-10-320.jpg)
The Ring programming language version 1.5.3 book - Part 30 of 184
- 1. Ring Documentation, Release 1.5.3 Output: sha512('hello') : 9b71d224bd62f3785d96d46ad3ea3d73319bfbc2890caadae2dff72519673c a72323c3d99ba5c11d7c7acc6e14b8c5da0c4663475c2e5c3adef46f73bcdec043 sha512('apple') : 844d8779103b94c18f4aa4cc0c3b4474058580a991fba85d3ca698a0bc9e52 c5940feb7a65a3a290e17e6b23ee943ecc4f73e7490327245b4fe5d5efb590feb2 sha512('hello world') : 309ecc489c12d6eb4cc40f50c902f2b4d0ed77ee511a7c7a9bcd3ca8 6d4cd86f989dd35bc5ff499670da34255b45b0cfd830e81f605dcf7dc5542e93ae9cd76f 38.5 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 38.6 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 38.7 Encrypt() Function We can use the Encrypt() function to encrypts the data using the Blowfish algorithm. 38.5. SHA384() Function 265
- 2. Ring Documentation, Release 1.5.3 Syntax: Encrypt(cString, cKey, cIV) ---> Encrypted string 38.8 Decrypt() Function We can use the Decrypt() function to decrypt the data encrypted using the Encrypt() function. Syntax: Decrypt(cCipher, cKey, cIV) ---> Decrypted string 38.9 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 38.10 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 38.8. Decrypt() Function 266
- 3. Ring Documentation, Release 1.5.3 38.11 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 38.12 Download() Function Syntax: Download(cURL) ---> String contains the server response Example: cStr= download("http://doublesvsoop.sourceforge.net/") see cStr write("download.txt",cStr) 38.13 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 38.11. Randbytes() Function 267
- 4. CHAPTER THIRTYNINE 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() 39.1 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] ] 268
- 5. Ring Documentation, Release 1.5.3 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 39.1. Classes and Objects 269
- 6. Ring Documentation, Release 1.5.3 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. 39.2 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 + 39.2. Access Objects Using Braces 270
- 7. Ring Documentation, Release 1.5.3 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 39.3 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: 39.3. Composition 271
- 8. Ring Documentation, Release 1.5.3 Name : Rectangle 1 Color: Blue P1 : (10,20) P2 : (200,300) 39.4 Setter and Getter We can define methods to be used when we set and get object attributes. Syntax: Class ClassName AttributeName ... Func SetAttributeName ... Func GetAttributeName ... Example: o1 = new person o1.name = "Mahmoud" see o1.name + nl o1 { name = "Ahmed" see name } Class Person name family = "Fayed" func setname value see "Message from SetName() Function!" + nl name = value + " " + family func getname see "Message from GetName() Function!" + nl return "Mr. " + name Output: Message from SetName() Function! Message from GetName() Function! Mr. Mahmoud Fayed Message from SetName() Function! Message from GetName() Function! Mr. Ahmed Fayed 39.5 Private Attributes and Methods We can define private attributes and methods after the keyword private inside the class body 39.4. Setter and Getter 272
- 9. Ring Documentation, Release 1.5.3 Example: o1 = new person { name = "Test" age = 20 print() o1.printsalary() } try see o1.salary catch see cCatchError + nl done try o1.increasesalary(1000) catch see cCatchError + nl done Class Person name age func print see "Name : " + name + nl + "Age : " + age + nl func printsalary see "Salary : " + salary + nl private salary = 15000 func increasesalary x salary += x Output: Name : Test Age : 20 Salary : 15000 Error (R27) : Using private attribute from outside the class : salary Error (R26) : Calling private method from outside the class : increasesalary 39.6 Operator Overloading We can add the operator method to our class to enable using operators with the class objects. Syntax: Class ClassName ... 39.6. Operator Overloading 273
- 10. Ring Documentation, Release 1.5.3 Func operator cOperator,Para ... The function operator takes two paramters, the first represent the operator and the second represent the second param- eter after the operator. Example: o1 = new point { x = 10 y = 10 print("P1 : ") } o2 = new point { x = 20 y = 40 print("P2 : ") } o3 = o1 + o2 o3.print("P1+P2 : ") class point x y func operator cOperator,Para result = new point switch cOperator on "+" result.x = x + Para.x result.y = y + Para.y on "-" result.x = x - Para.x result.y = y - Para.y off return result func print cPoint see cPoint + "X : " + x + " Y : " + y + nl Output: P1 : X : 10 Y : 10 P2 : X : 20 Y : 40 P1+P2 : X : 30 Y : 50 39.7 Inheritance We can create class from another class in the class definition using the keyword from. Syntax: Class <Class Name> [From <Parent Class Name>] We can call a method in the parent class from the child class using the super object. Syntax: func methodname ... super.methodname() ... Example: 39.7. Inheritance 274