The Ring programming language version 1.5.2 book - Part 9 of 181

1. Ring Documentation, Release 1.5.2
glLoadIdentity()
// Rotate when user changes rotate_x and rotate_y
glRotatef( rotate_x, 1.0, 0.0, 0.0 )
glRotatef( rotate_y, 0.0, 1.0, 0.0 )
//Multi-colored side - FRONT
glBegin(GL_POLYGON)
glColor3f( 1.0, 0.0, 0.0 ) glVertex3f( 0.5, -0.5, -0.5 ) # P1 is red
glColor3f( 0.0, 1.0, 0.0 ) glVertex3f( 0.5, 0.5, -0.5 ) # P2 is green
glColor3f( 0.0, 0.0, 1.0 ) glVertex3f( -0.5, 0.5, -0.5 ) # P3 is blue
glColor3f( 1.0, 0.0, 1.0 ) glVertex3f( -0.5, -0.5, -0.5 ) # P4 is purple
glEnd()
// White side - BACK
glBegin(GL_POLYGON)
glColor3f( 1.0, 1.0, 1.0 )
glVertex3f( 0.5, -0.5, 0.5 )
glVertex3f( 0.5, 0.5, 0.5 )
glVertex3f( -0.5, 0.5, 0.5 )
glVertex3f( -0.5, -0.5, 0.5 )
glEnd()
// Purple side - RIGHT
glBegin(GL_POLYGON)
glColor3f( 1.0, 0.0, 1.0 )
glVertex3f( 0.5, -0.5, -0.5 )
glVertex3f( 0.5, 0.5, -0.5 )
glVertex3f( 0.5, 0.5, 0.5 )
glVertex3f( 0.5, -0.5, 0.5 )
glEnd()
// Green side - LEFT
glBegin(GL_POLYGON)
glColor3f( 0.0, 1.0, 0.0 )
glVertex3f( -0.5, -0.5, 0.5 )
glVertex3f( -0.5, 0.5, 0.5 )
glVertex3f( -0.5, 0.5, -0.5 )
glVertex3f( -0.5, -0.5, -0.5 )
glEnd()
// Blue side - TOP
glBegin(GL_POLYGON)
glColor3f( 0.0, 0.0, 1.0 )
glVertex3f( 0.5, 0.5, 0.5 )
glVertex3f( 0.5, 0.5, -0.5 )
glVertex3f( -0.5, 0.5, -0.5 )
glVertex3f( -0.5, 0.5, 0.5 )
glEnd()
// Red side - BOTTOM
glBegin(GL_POLYGON)
glColor3f( 1.0, 0.0, 0.0 )
glVertex3f( 0.5, -0.5, -0.5 )
glVertex3f( 0.5, -0.5, 0.5 )
glVertex3f( -0.5, -0.5, 0.5 )
4.11. RingOpenGL Extension 55

2. Ring Documentation, Release 1.5.2
glVertex3f( -0.5, -0.5, -0.5 )
glEnd()
glFlush()
glutSwapBuffers()
// ----------------------------------------------------------
// specialKeys() Callback Function
// ----------------------------------------------------------
func specialKeys
key = glutEventKey()
// Right arrow - increase rotation by 5 degree
switch Key
on GLUT_KEY_RIGHT
rotate_y += 5
// Left arrow - decrease rotation by 5 degree
on GLUT_KEY_LEFT
rotate_y -= 5
on GLUT_KEY_UP
rotate_x += 5
on GLUT_KEY_DOWN
rotate_x -= 5
off
// Request display update
glutPostRedisplay()
// ----------------------------------------------------------
// main() function
// ----------------------------------------------------------
func main
// Initialize GLUT and process user parameters
glutInit()
// Request double buffered true color window with Z-buffer
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
// Create window
glutCreateWindow("Awesome Cube")
// Enable Z-buffer depth test
glEnable(GL_DEPTH_TEST)
// Callback functions
glutDisplayFunc(:display)
glutSpecialFunc(:specialKeys)
4.11. RingOpenGL Extension 56

3. Ring Documentation, Release 1.5.2
// Pass control to GLUT for events
glutMainLoop()
// Return to OS
Screen Shot:
4.12 Better Code Generator for Extensions
The Code Generator is updated to support <constant> type, So we can have constants other than numbers, for example
: Strings and Pointers.
When we have pointers we can determine the pointer type. To use this feature, before <constant> and </constant> we
can use
$nDefaultConstantType = C_CONSTANT_TYPE_POINTER
$cDefaultConstantPointerType = "void *"
The next example from the RingFreeGLUT extension
<runcode>
$nDefaultConstantType = C_CONSTANT_TYPE_POINTER
$cDefaultConstantPointerType = "void"
</runcode>
<constant>
GLUT_STROKE_ROMAN
GLUT_STROKE_MONO_ROMAN
GLUT_BITMAP_9_BY_15
GLUT_BITMAP_8_BY_13
GLUT_BITMAP_TIMES_ROMAN_10
GLUT_BITMAP_TIMES_ROMAN_24
GLUT_BITMAP_HELVETICA_10
GLUT_BITMAP_HELVETICA_12
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4. Ring Documentation, Release 1.5.2
GLUT_BITMAP_HELVETICA_18
</constant>
4.13 Better Documentation Generator for Extensions
The documentation generator for extensions is updated to generate a list of constants in the generated documentation
The previous versions provides the functions prototype only, Now we have the list of constants too.
4.14 Ring VM - Tracing Functions
In Ring 1.5 the next functions are added to Ring VM
• RingVM_SetTrace(cCode)
• RingVM_TraceData() –> aDataList
• RingVM_TraceEvent() –> nTraceEvent
• RingVM_TraceFunc() –> cCode
• RingVM_ScopesCount() –> nScopes
• RingVM_EvalInScope(nScope,cCode)
• RingVM_PassError()
• RingVM_HideErrorMsg(lStatus)
• RingVM_CallFunc(cFuncName)
Example:
load "tracelib.ring"
ringvm_settrace("mytrace()")
see "Hello, world!" + nl
see "Welcome" + nl
see "How are you?" +nl
mytest()
new myclass { mymethod() }
func mytest
see "Message from mytest" + nl
func mytrace
see "====== The Trace function is Active ======" + nl +
"Trace Function Name : " + ringvm_TraceFunc() + nl +
"Trace Event : "
switch ringvm_TraceEvent()
on TRACEEVENT_NEWLINE see "New Line"
on TRACEEVENT_NEWFUNC see "New Function"
on TRACEEVENT_RETURN see "Return"
on TRACEEVENT_ERROR see "Error"
on TRACEEVENT_BEFORECFUNC see "Before C Function"
on TRACEEVENT_AFTERCFUNC see "After C Function"
off
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5. Ring Documentation, Release 1.5.2
see nl +
"Line Number : " + ringvm_tracedata()[TRACEDATA_LINENUMBER] + nl +
"File Name : " + ringvm_tracedata()[TRACEDATA_FILENAME] + nl +
"Function Name : " + ringvm_tracedata()[TRACEDATA_FUNCNAME] + nl +
"Method or Function : "
if ringvm_tracedata()[TRACEDATA_METHODORFUNC] =
TRACEDATA_METHODORFUNC_METHOD
see "Method"
else
if ringvm_tracedata()[TRACEDATA_FUNCNAME] = NULL
see "Command"
else
see "Function"
ok
ok
see nl + Copy("=",42) + nl
class myclass
func mymethod
see "Message from mymethod" + nl
Output:
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : After C Function
Line Number : 3
File Name : test1.ring
Function Name : ringvm_settrace
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 5
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
Hello, world!
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 6
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
Welcome
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 7
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
How are you?
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6. Ring Documentation, Release 1.5.2
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 8
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Function
Line Number : 8
File Name : test1.ring
Function Name : mytest
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 12
File Name : test1.ring
Function Name : mytest
Method or Function : Function
==========================================
Message from mytest
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 14
File Name : test1.ring
Function Name : mytest
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : Return
Line Number : 8
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 9
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 43
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
====== The Trace function is Active ======
4.14. Ring VM - Tracing Functions 60

7. Ring Documentation, Release 1.5.2
Trace Function Name : mytrace()
Trace Event : Before C Function
Line Number : 9
File Name : test1.ring
Function Name : ismethod
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : After C Function
Line Number : 9
File Name : test1.ring
Function Name : ismethod
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Function
Line Number : 9
File Name : test1.ring
Function Name : mymethod
Method or Function : Method
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 44
File Name : test1.ring
Function Name : mymethod
Method or Function : Method
==========================================
Message from mymethod
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : Return
Line Number : 9
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : Before C Function
Line Number : 9
File Name : test1.ring
Function Name : ismethod
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : After C Function
Line Number : 9
File Name : test1.ring
Function Name : ismethod
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
4.14. Ring VM - Tracing Functions 61

8. Ring Documentation, Release 1.5.2
Trace Event : Before C Function
Line Number : 9
File Name : test1.ring
Function Name : ismethod
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : After C Function
Line Number : 9
File Name : test1.ring
Function Name : ismethod
Method or Function : Function
==========================================
====== The Trace function is Active ======
Trace Function Name : mytrace()
Trace Event : New Line
Line Number : 11
File Name : test1.ring
Function Name :
Method or Function : Command
==========================================
4.15 Trace Library and Interactive Debugger
Ring 1.5 comes with the Trace Library and the Interactive Debugger
Using this library we can trace events, execute programs line by line, open the Interactive Debugger when an error
happens or at breakpoints.
Example:
The next example uses a Breakpoint to open the Interactive Debugger!
load "tracelib.ring"
test1()
func test1
x = 10
see :test1 + nl
t = 12
BreakPoint()
see "After breakpoint!" +nl
see "t = " + t + nl
see "End of program!" + nl
Screen Shots:
We have the Interactive Debugger at the Breakpoint!
4.15. Trace Library and Interactive Debugger 62

9. Ring Documentation, Release 1.5.2
We can print the variables values
We can change the variables values then continue execution
We can run the Interactive Debugger in the Output Window
4.15. Trace Library and Interactive Debugger 63

10. Ring Documentation, Release 1.5.2
4.16 More Syntax Flexibility
• Using braces { } in Packages/Classes/Functions
Example:
load "stdlib.ring"
import mypackage
new myclass {
myfunc()
}
package mypackage
{
class myclass
{
func myfunc
{
print("Hello, World!n")
}
}
}
• Using ‘end’ keyword after Packages/Classes/Functions
Example:
import mypackage
new myclass {
myfunc()
}
4.16. More Syntax Flexibility 64