The Ring programming language version 1.5.1 book - Part 6 of 180

1. Ring Documentation, Release 1.5.1
3.11 Smart Garbage Collector
Avoid memory problems :-
• Invalid Memory Access
• Memory leaks
• Uninitialized Memory Access
• Dangling pointer
Rules :-
• Global variables always stay in the memory, until you delete these variables using the assignment statement.
• Local variables always deleted after the end of the function.
• The programmer have full control on when to delete the variable from the memory using the Assignment state-
ment.
Example:
aList = [1,2,3,4,5]
aList = "nice"
After the second line directly, The list [1,2,3,4,5] will be deleted from the memory and we will have a string “nice”
• The programmer can call the function callgc() to force running the garbage collector.
• If we have a reference to a variable (when we pass objects and lists to functions), then deleting variables will be
based on reference counting, if no references everything will be deleted, but if we have a reference, the data will
stay in memory.
3.11. Smart Garbage Collector 25

2. CHAPTER
FOUR
WHAT IS NEW IN RING 1.5?
In this chapter we will learn about the changes and new features in Ring 1.5 release.
4.1 List of changes and new features
Ring 1.5 comes with many new features!
• Video-Music-Player Application
• Windows StartUp Manager Application
• Calculator Application
• Better Ring Notepad
• Better StdLib
• Better WebLib
• Better RingQt
• Better Objects Library
• RingFreeGLUT Extension
• RingOpenGL Extension
• Better Code Generator for Extensions
• Better Documentation Generator for Extensions
• Ring VM - Tracing Functions
• Trace Library and Interactive Debugger
• More Syntax Flexibility
• Type Hints Library
• Better Quality
4.2 Video-Music-Player Application
The Video-Music-Player application is added to the Applications folder.
Screen Shot:
26

3. Ring Documentation, Release 1.5.1
4.3 Windows StartUp Manager Application
The Windows StartUp Manager
URL : https://github.com/ring-lang/WinStartupManager
Screen Shot:
4.3. Windows StartUp Manager Application 27

4. Ring Documentation, Release 1.5.1
4.4 Calculator Application
The Calculator application is added to the Applications folder.
Screen Shot:
4.5 Better Ring Notepad
1. Ring Notepad is updated to include some new styles and the Main File ToolBar
The idea of the Main File ToolBar is to determine the main file in the project When the project contains many source
code files
This way you can run the project ( Main File ) at any time while opening other files in the project without the need to
switch to the Main File to run the project.
To quickly use this feature
(Open the project main file)
Press Ctrl+Shift+M to set the current source code file as the main file
Open and modify other source code files in the project
To run the project (Main File) at any time press Ctrl+Shift+F5 (GUI) or Ctrl+Shift+D (Console)
Screen Shots:
4.4. Calculator Application 28

5. Ring Documentation, Release 1.5.1
4.5. Better Ring Notepad 29

6. Ring Documentation, Release 1.5.1
2. The output window is updated to display the new lines correctly and contains the “Clear” button.
Screen Shot:
(3) The Ring Notepad is updated to quickly open and switch between large files while preparing the functions/classes
lists in the background.
Screen Shot:
4.5. Better Ring Notepad 30

7. Ring Documentation, Release 1.5.1
4.6 Better StdLib
New Functions
• Print2Str()
• ListAllFiles()
• SystemCmd()
1. The Print2Str() is a new function added to the StdLib
Example:
load "stdlib.ring"
world = "World!"
mystring = print2str("Hello, #{world} nIn Year n#{2000+17} n")
see mystring + nl
Output:
Hello, World!
In Year
2017
2. The ListAllFiles() is a new function added to the StdLib
Using this function we can quickly do a process on a group of files in a folder and it’s sub folders.
Example:
load "stdlib.ring"
aList = ListAllFiles("c:/ring/ringlibs","ring") # *.ring only
4.6. Better StdLib 31

8. Ring Documentation, Release 1.5.1
aList = sort(aList)
see aList
Example:
load "stdlib.ring"
see listallfiles("b:/ring/ringlibs/weblib","") # All Files
3. The SystemCmd() is a new function added to the StdLib
The function will execute a system command like the System() function but will return the output in a string.
Example:
cYou = SystemCmd("whoami")
See "SystemCmd: whoami ====="+ nl + cYou +nl
Output:
SystemCmd: whoami =====
desktop-umbertoumberto
4.7 Better WebLib
The WebLib is updated to include the HTMLPage class
Using this class we can create HTML documents without printing the output to the standard output
So instead of using the WebLib in Web Applications only
We can use it in Console/GUI/Mobile Applications too
Example:
load "stdlib.ring"
load "weblib.ring"
import System.Web
func main
mypage = new HtmlPage {
h1 { text("Customers Report") }
Table
{
style = stylewidth("100%") + stylegradient(4)
TR
{
TD { WIDTH="10%" text("Customers Count : " ) }
TD { text (100) }
}
}
Table
{
style = stylewidth("100%") + stylegradient(26)
TR
{
style = stylewidth("100%") + stylegradient(24)
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9. Ring Documentation, Release 1.5.1
TD { text("Name " ) }
TD { text("Age" ) }
TD { text("Country" ) }
TD { text("Job" ) }
TD { text("Company" ) }
}
for x = 1 to 100
TR
{
TD { text("Test" ) }
TD { text("30" ) }
TD { text("Egypt" ) }
TD { text("Sales" ) }
TD { text("Future" ) }
}
next
}
}
write("report.html",mypage.output())
Using this feature we can create reports quickly using WebLib & GUILib together
Example:
load "stdlib.ring"
load "weblib.ring"
load "guilib.ring"
import System.Web
import System.GUI
new qApp {
open_window(:CustomersReportController)
exec()
}
class CustomersReportController
oView = new CustomersReportView
func Start
CreateReport()
func CreateReport
mypage = new HtmlPage {
h1 { text("Customers Report") }
Table
{
style = stylewidth("100%") + stylegradient(4)
TR
{
TD { WIDTH="10%"
text("Customers Count : " ) }
TD { text (100) }
}
}
Table
4.7. Better WebLib 33

10. Ring Documentation, Release 1.5.1
{
style = stylewidth("100%") + stylegradient(26)
TR
{
style = stylewidth("100%") +
stylegradient(24)
TD { text("Name " ) }
TD { text("Age" ) }
TD { text("Country" ) }
TD { text("Job" ) }
TD { text("Company" ) }
}
for x = 1 to 100
TR
{
TD { text("Test" ) }
TD { text("30" ) }
TD { text("Egypt" ) }
TD { text("Sales" ) }
TD { text("Future" ) }
}
next
}
}
write("report.html",mypage.output())
func PrintEvent
printer1 = new qPrinter(0) {
setoutputformat(1)
setoutputfilename("report.pdf")
}
oView {
web.print(printer1)
web.show()
}
system ("report.pdf")
class CustomersReportView
win = new window() {
setwindowtitle("Report Window")
setgeometry(100,100,500,500)
web = new webview(win) {
setgeometry(100,100,1000,500)
loadpage(new qurl("file:///"+
currentdir()+"/report.html"))
}
new pushbutton(win) {
setGeometry(100,20,100,30)
settext("Print")
setclickevent(Method(:PrintEvent))
}
showMaximized()
}
Screen Shot:
4.7. Better WebLib 34