The Ring programming language version 1.8 book - Part 38 of 202

Ring Documentation, Release 1.8
Example:
See packages()
Package Package1
Class class1
Func f1
Package Package2
Class class1
Func f1
Package Package3
Class class1
Func f1
Package Package4
Class class1
Func f1
Output:
package1
package2
package3
package4
44.10 ispackage() Function
We can check if a package is deﬁned or not using the ispackage() function.
Syntax:
ispackage(cPackageName) --> returns 1 if the Package is defined
returns 0 if the Package is not defined
Example:
See ispackage("package1") + nl +
ispackage("package4") + nl +
ispackage("package5") + nl +
ispackage("package3") + nl
Package Package1
Class class1
Func f1
Package Package2
Class class1
Func f1
Package Package3
Class class1
Func f1
Package Package4
Class class1
Func f1
44.10. ispackage() Function 341

Output:
1
1
0
1
44.11 classes() Function
We can get a list of classes names using the classes() function.
Syntax:
classes() --> a list contains classes names
Example:
See classes()
Class class1
Func f1
Class class2
Func f1
Class class3
Func f1
Output:
class1
class2
class3
44.12 isclass() Function
We can check if a class is deﬁned or not using the isclass() function.
Syntax:
isclass(cClassName) --> returns 1 if the Class is defined
returns 0 if the Class is not defined
Example:
see isclass("class4") + nl +
isclass("class3") + nl +
isclass("class2") + nl
Class class1
func f1
class class2
func f1
class class3
func f1
44.11. classes() Function 342

Output:
0
1
1
44.13 packageclasses() Function
We can get a list of classes names inside a package using the packageclasses() function.
Syntax:
packageclasses(cPackageName) --> a list contains classes names inside the package
Example:
see "classes in Package1" + nl
see packageclasses("Package1")
see "classes in Package2" + nl
see packageclasses("Package2")
Package Package1
Class class1
Func f1
Package Package2
Class class1
Func f1
Class class2
Func f1
Class class3
func f1
Output:
classes in Package1
class1
classes in Package2
class1
class2
class3
44.14 ispackageclass() Function
We can check if a class is deﬁned inside package or not using the ispackageclass() function.
Syntax:
ispackageclass(cPackageName,cClassName) --> returns 1 if the Class is defined
returns 0 if the Class is not defined
Example:
see ispackageclass("package1","class1") + nl +
ispackageclass("package1","class2") + nl +
ispackageclass("package2","class1") + nl +
44.13. packageclasses() Function 343

ispackageclass("package2","class2") + nl
Package Package1
Class class1
Func f1
Package Package2
Class class1
Func f1
Class class2
Func f1
Class class3
func f1
Output:
1
0
1
1
44.15 classname() Function
We can know the class name of an object using the classname() function
Syntax:
classname(object) --> Returns the object class name
Example:
o1 = new point
o2 = new rect
see classname(o1) + nl # print point
see classname(o2) + nl # print rect
class point
class rect
44.16 objectid() Function
We can know the object id using the objectid() function
Syntax:
objectid(object) --> Returns the object id
Example:
o1 = new point
see objectid(o1) + nl
test(o1)
func test v
see objectid(v) + nl
44.15. classname() Function 344

Class point x y z
Output:
021B5808
021B5808
44.17 isobject() Function
We can check the variable to know if it’s an object or not using the isobject() function
Syntax:
isobject(variable) --> Returns True if it's an object, False if it's not
44.18 attributes() Function
We can get the object attributes using the attributes() function
Syntax:
attributes(object) --> Returns a list contains the object attributes
Example:
o1 = new point
aList = attributes(o1) # we can use see attributes(o1)
for t in aList see t next # print xyz
Class Point x y z
44.19 methods() Function
We can get the object methods using the methods() function
Syntax:
methods(object) --> Returns a list contains the object methods
Example:
o1 = new test
aList = methods(o1)
for x in aList
cCode = "o1."+x+"()"
eval(cCode)
next
Class Test
func f1
see "hello from f1" + nl
func f2
44.17. isobject() Function 345

func f3
func f4
Output:
hello from f1
hello from f2
hello from f3
hello from f4
44.20 isattribute() Function
We can test if the object contains an attribute or not using the isattribute() function
Syntax:
isattribute(object,cAttributeName) --> Returns True if the object contains the attribute
Example:
o1 = new point
see isattribute(o1,"x") + nl # print 1
see isattribute(o1,"t") + nl # print 0
see isattribute(o1,"y") + nl # print 1
see isattribute(o1,"z") + nl # print 1
class point x y z
44.21 isprivateattribute() Function
We can test if the object contains a private attribute or not using the isprivateattribute() function
Syntax:
isprivateattribute(object,cAttributeName) --> Returns True if the object
contains the private attribute
Example:
o1 = new person
see isprivateattribute(o1,"name") + nl +
isprivateattribute(o1,"address") + nl +
isprivateattribute(o1,"phone") + nl +
isprivateattribute(o1,"job") + nl +
isprivateattribute(o1,"salary")
Class Person
name address phone
private
job salary
44.20. isattribute() Function 346

Output:
0
0
0
1
1
44.22 ismethod() Function
We can test if the object class contains a method or not using the ismethod() function
Syntax:
ismethod(object,cMethodName) --> Returns True if the object class contains the method
Example:
o1 = new point
see ismethod(o1,"print") + nl # print 1
mylist = []
mylist + new point
see ismethod(mylist[1],"print") + nl # print 1
class point x y z
func print
see x + nl + y + nl + z + nl
44.23 isprivatemethod() Function
We can test if the object class contains a private method or not using the isprivatemethod() function
Syntax:
isprivatemethod(object,cMethodName) --> Returns True if the object class contains
the private method
Example:
o1 = new Test
see isprivatemethod(o1,"f1") + nl +
isprivatemethod(o1,"f2")
Class Test
func f1
see "message from f1()" + nl
private
func f2
see "message from f2()" + nl
Output:
44.22. ismethod() Function 347

0
1
44.24 addattribute() Function
We can add an attribute (or a group of attributes) to the object state (not the class) using the addattribute() function
Syntax:
AddAttribute(object,cAttributeName|aAttributesList)
Example(1):
see new point {x=10 y=20 z=30}
Class Point
AddAttribute(self,["x","y","z"])
Example(2):
o1 = new point
addattribute(o1,"x")
addattribute(o1,"y")
addattribute(o1,"z")
see o1 {x=10 y=20 z=30}
class point
Output:
x: 10.000000
y: 20.000000
z: 30.000000
44.25 addmethod() Function
We can add a method to the object class using the addmethod() function This method can be used with any object from
the same class.
Syntax:
AddMethod(Object,cNewMethodName,cMethodName|AnonymousFunction)
Example:
o1 = new point { x=10 y=20 z=30 }
addmethod(o1,"print", func { see x + nl + y + nl + z + nl } )
o1.print()
Class point
x y z
Output:
44.24. addattribute() Function 348

10
20
30
Instead of using anonymous function to add new method to the class, we can use the function name
Example:
o1 = new point { x=10 y=20 z=30 }
myfunc = func { see x + nl + y + nl + z + nl }
addmethod(o1,"print", myfunc )
addmethod(o1,"display", myfunc )
addmethod(o1,"show", myfunc )
o1.print()
o1.display()
o1.show()
Class point
x y z
Output:
10
20
30
10
20
30
10
20
30
Since we add the method to the class, any object from that class can use this method
Example:
o1 = new point { x=10 y=20 z=30 }
o2 = new point { x=100 y=200 z=300 }
o3 = new point { x=50 y=150 z=250 }
addmethod(o1,"print", func { see x + nl + y + nl + z + nl } )
o1.print()
o2.print()
o3.print()
Class point
x y z
Output:
10
20
30
100
200
300
44.25. addmethod() Function 349

50
150
250
44.26 getattribute() function
We can get the object attribute value using the getattribute() function
Syntax:
GetAttribute(oObject,cAttributeName) ---> Attribute Value
Example:
o1 = new point
see getattribute(o1,"name") + nl +
getattribute(o1,"x") + nl +
getattribute(o1,"y") + nl +
getattribute(o1,"z") + nl
Class Point
x=10 y=20 z=30
name = "3D-Point"
Output:
3D-Point
10
20
30
Example:
We can Find a Class List Member using GetAttribute() using a function ﬁndclass() The Find uses the member name,
rather than the column number
myList =
[new Company {position=3 name="Mahmoud" symbol="MHD"},
new Company {position=2 name="Bert" symbol="BRT"},
new Company {position=1 name="Ring" symbol="RNG"}
]
see myList
see nl +"=====================" + nl + nl
for i = 1 to len(myList)
see "Pos: "+ i +" | "+ myList[i].position +" | "+ myList[i].name +
" | "+ myList[i].symbol +" | "+ nl
next
See findclass(myList, "MHD", "symbol") +nl ### Specify Member class name
###---------------------------------------
func findclass classList, cValue, classMember
44.26. getattribute() function 350

The Ring programming language version 1.8 book - Part 38 of 202

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The Ring programming language version 1.8 book - Part 38 of 202