The Ring programming language version 1.9 book - Part 93 of 210

1. Ring Documentation, Release 1.9
79.2 Serial Execution of Programs
We can execute application after another application using ring_state_main()
Example:
chdir(exefolder()+"/../applications/formdesigner")
ring_state_main('formdesigner.ring')
chdir(exefolder()+"/../applications/cards")
ring_state_main('cards.ring')
79.3 ring_state_setvar()
Using ring_state_setvar() we can set variables value
The value could be (String, Number, List or C Pointer)
We need this function to quickly pass lists and C pointers to the Sub Ring Environment
Syntax:
ring_state_setvar(oState,cVariableName,Value)
Example:
load "guilib.ring"
myapp = null
win = null
func main
myapp = new qApp {
win = new qWidget() {
setWindowTitle("Advanced Example on using ring_state_setvar()")
move(100,100)
resize(600,400)
new qPushButton(win) {
setText("Test")
setClickEvent("Test()")
}
# We need this because using load 'guilib.ring' in
# the sub environment
# Will create timers by Qt and closing the window
# will not be enough to close the application
oFilter = new qAllEvents(win)
oFilter.setCloseEvent("myapp.quit()")
win.installeventfilter(oFilter)
show()
}
exec()
}
func test
pState = ring_state_init()
ring_state_runcode(pstate,"load 'guilib.ring'")
ring_state_runcode(pState,"x = NULL")
# Pass String
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ring_state_setvar(pState,"x","hello")
ring_state_runcode(pState,"? x")
# Pass Number
ring_state_setvar(pState,"x",100)
ring_state_runcode(pState,"? x")
# Pass List
ring_state_setvar(pState,"x",["one","two","three"])
ring_state_runcode(pState,"? x")
# Pass Object
# We can't pass the Ring Object (win)
# Because Objects store pointers to the Class Information
# And the class is related to the Parent Ring Environment
# And the sub Ring environment can't access it
# But we can pass C pointers like win.pObject
ring_state_setvar(pState,"x",win.pObject)
# Now we create the object again but using the same C pointer
# So we have access to the Same window in the parent Ring enviroment
ring_state_runcode(pState,"
new qWidget {
pObject = x
setwindowtitle('Message from the Sub Ring Environment')
}
")
ring_state_delete(pState)
79.4 ring_state_new() and ring_state_mainfile()
Using ring_state_new() and ring_state_mainfile() we can run Ring programs from Ring programs
But unlike ring_state_main(), Here we can control when to delete the Ring state!
This is important when we run GUI programs from GUI programs
Because they will share the GUI Library (RingQt), And In this case the caller will call
qApp.Exec()
So the sub program, will not stop and will return to the Main program
Here deleting the State of the sub programs will lead to a problem when we run the sub program events
So keeping the state is important for sub GUI programs hosted in GUI programs.
Example:
load "guilib.ring"
func main
new qApp {
win = new qWidget() {
setWindowTitle("Test ring_state_mainfile()")
resize(400,400) move(100,100)
btn = new qPushButton(Win) {
settext("test")
setclickevent("mytest()")
}
show()
}
exec()
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}
func mytest
pState = ring_state_new()
ring_state_mainfile(pState,"runprogram.ring")
# Here we don't delete the state if we will run GUI application
# So we can run the GUI application events
// ring_state_delete(pState)
If you will use this feature, remember to update the previous example based on your application needs
So you can call ring_state_delete() at some point to avoid the memory leak!
79.5 Runtime Errors when Embedding Ring in Ring
Starting from Ring 1.8
When embedding Ring in Ring, the error in the hosted environment will not close the host
Example:
? "Start the test!"
pState = ring_state_init()
ring_state_runcode(pState," ? 'Let us try having an error' ? x")
ring_state_delete(pState)
? ""
? "End of test!"
Output:
Start the test!
Let us try having an error
Line 1 Error (R24) : Using uninitialized variable : x
in file Ring_EmbeddedCode
End of test!
79.5. Runtime Errors when Embedding Ring in Ring 891

4. CHAPTER
EIGHTY
EXTENSION USING THE C/C++ LANGUAGES
We can extend the Ring Virtual Machine (RingVM) by adding new functions written in the C programming language
or C++. The RingVM comes with many functions written in C that we can call like any Ring function.
We can extend the language by writing new functions then rebuilding the RingVM again, or we can create shared
library (DLL/So) file to extend the RingVM without the need to rebuild it.
The Ring language source code comes with two files to add new modules to the RingVM, ring_ext.h and ring_ext.c
80.1 ring_ext.h
The file ring_ext.h contains constants that we can change to include/exclude modules during the build process.
#ifndef ringext_h
#define ringext_h
/* Constants */
#define RING_VM_LISTFUNCS 1
#define RING_VM_REFMETA 1
#define RING_VM_MATH 1
#define RING_VM_FILE 1
#define RING_VM_OS 1
#define RING_VM_MYSQL 1
#define RING_VM_ODBC 1
#define RING_VM_OPENSSL 1
#define RING_VM_CURL 1
#define RING_VM_DLL 1
#endif
80.2 ring_ext.c
The file ring_ext.c check constants defined in ring_ext.h before calling the start-up function in each module.
Each module contains a function that register the module functions in the RingVM.
#include "ring.h"
void ring_vm_extension ( RingState *pRingState )
{
/* Reflection and Meta-programming */
#if RING_VM_REFMETA
ring_vm_refmeta_loadfunctions(pRingState);
#endif
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/* List Functions */
#if RING_VM_LISTFUNCS
ring_vm_listfuncs_loadfunctions(pRingState);
#endif
/* Math */
#if RING_VM_MATH
ring_vm_math_loadfunctions(pRingState);
#endif
/* File */
#if RING_VM_FILE
ring_vm_file_loadfunctions(pRingState);
#endif
/* OS */
#if RING_VM_OS
ring_vm_os_loadfunctions(pRingState);
#endif
/* MySQL */
#if RING_VM_MYSQL
ring_vm_mysql_loadfunctions(pRingState);
#endif
/* ODBC */
#if RING_VM_ODBC
ring_vm_odbc_loadfunctions(pRingState);
#endif
/* OPENSSL */
#if RING_VM_OPENSSL
ring_vm_openssl_loadfunctions(pRingState);
#endif
/* CURL */
#if RING_VM_CURL
ring_vm_curl_loadfunctions(pRingState);
#endif
/* DLL */
#if RING_VM_DLL
ring_vm_dll_loadfunctions(pRingState);
#endif
}
80.3 Module Organization
Each module starts by include the ring header file (ring.h). This files contains the Ring API that we can use to extend
the RingVM.
Each module comes with a function to register the module functions in the RingVM The registration is done by using
ring_vm_funcregister() function.
The ring_vm_funcregister() function takes two parameters, the first is the function name that will be used by Ring
programs to call the function. The second parameter is the function pointer in the C program.
for example, the ring_vmmath.c module contains the next code to register the module functions
#include "ring.h"
void ring_vm_math_loadfunctions ( RingState *pRingState )
{
ring_vm_funcregister("sin",ring_vm_math_sin);
ring_vm_funcregister("cos",ring_vm_math_cos);
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ring_vm_funcregister("tan",ring_vm_math_tan);
ring_vm_funcregister("asin",ring_vm_math_asin);
ring_vm_funcregister("acos",ring_vm_math_acos);
ring_vm_funcregister("atan",ring_vm_math_atan);
ring_vm_funcregister("atan2",ring_vm_math_atan2);
ring_vm_funcregister("sinh",ring_vm_math_sinh);
ring_vm_funcregister("cosh",ring_vm_math_cosh);
ring_vm_funcregister("tanh",ring_vm_math_tanh);
ring_vm_funcregister("exp",ring_vm_math_exp);
ring_vm_funcregister("log",ring_vm_math_log);
ring_vm_funcregister("log10",ring_vm_math_log10);
ring_vm_funcregister("ceil",ring_vm_math_ceil);
ring_vm_funcregister("floor",ring_vm_math_floor);
ring_vm_funcregister("fabs",ring_vm_math_fabs);
ring_vm_funcregister("pow",ring_vm_math_pow);
ring_vm_funcregister("sqrt",ring_vm_math_sqrt);
ring_vm_funcregister("unsigned",ring_vm_math_unsigned);
ring_vm_funcregister("decimals",ring_vm_math_decimals);
ring_vm_funcregister("murmur3hash",ring_vm_math_murmur3hash);
}
Tip: Remember that the function ring_vm_math_loadfunctions() will be called by the ring_vm_extension() function
(in the ring_ext.c file).
80.4 Function Structure
Each module function may contains the next steps
1 - Check Parameters Count
2 - Check Parameters Type
3 - Get Parameters Values
4 - Execute Code/Call Functions
5 - Return Value
The structure is very similar to any function (Input - Process - Output) But here we will use the Ring API for the steps
1,2,3 and 5.
80.5 Check Parameters Count
We can check the parameters count using the RING_API_PARACOUNT macro.
We can compare RING_API_PARACOUNT with any numeric value using == or != operators.
Example:
if ( RING_API_PARACOUNT != 1 ) {
/* code */
}
Example:
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if ( RING_API_PARACOUNT == 1 ) {
/* code */
}
80.6 Display Error Message
We can display error messages using the RING_API_ERROR() function.
The function will display the error and end the execution of the program.
Note: the behaviour of this function can be changed by the Ring code using Try/Catch/Done statements, so in your C
code, use Return after this function.
Syntax:
RING_API_ERROR(const char *cErrorMsg);
The Ring API comes with some of predefined error messages that we can use
#define RING_API_MISS1PARA "Bad parameters count, the function expect one parameter"
#define RING_API_MISS2PARA "Bad parameters count, the function expect two parameters"
#define RING_API_MISS3PARA "Bad parameters count, the function expect three parameters"
#define RING_API_MISS4PARA "Bad parameters count, the function expect four parameters"
#define RING_API_BADPARATYPE "Bad parameter type!"
#define RING_API_BADPARACOUNT "Bad parameters count!"
#define RING_API_BADPARARANGE "Bad parameters value, error in range!"
#define RING_API_NOTPOINTER "Error in parameter, not pointer!"
#define RING_API_NULLPOINTER "Error in parameter, NULL pointer!"
#define RING_API_EMPTYLIST "Bad parameter, empty list!"
80.7 Check Parameters Type
We can check the parameter type using the next functions
int RING_API_ISNUMBER(int nParameterNumber);
int RING_API_ISSTRING(int nParameterNumber);
int RING_API_ISLIST(int nParameterNumber);
int RING_API_ISPOINTER(int nParameterNumber);
The output of these functions will be 1 (True) or 0 (False).
80.8 Get Parameters Values
We can get paramters values using the next functions
double RING_API_GETNUMBER(int nParameterNumber);
const char *RING_API_GETSTRING(int nParameterNumber);
int RING_API_GETSTRINGSIZE(int nParameterNumber);
List *RING_API_GETLIST(int nParameterNumber);
void *RING_API_GETCPOINTER(int nParameterNumber, const char *cPoinerType);
int RING_API_GETPOINTERTYPE(int nParameterNumber);
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80.9 Return Value
We can return values from our function using the next functions.
RING_API_RETNUMBER(double nValue);
RING_API_RETSTRING(const char *cString);
RING_API_RETSTRING2(const char *cString,int nStringSize);
RING_API_RETLIST(List *pList);
RING_API_RETCPOINTER(void *pValue,const char *cPointerType);
RING_API_RETMANAGEDCPOINTER(void *pValue,const char *cPointerType,
void (* pFreeFunc)(void *,void *))
80.10 Function Prototype
When we define new function to be used for RingVM extension, we use the next prototype
void my_function_name( void *pPointer );
or we can use the RING_FUNC() Macro
RING_FUNC(my_function_name);
80.11 Sin() Function Implementation
The next code represents the sin() function implementation using the Ring API and the sin() C function.
void ring_vm_math_sin ( void *pPointer )
{
if ( RING_API_PARACOUNT != 1 ) {
RING_API_ERROR(RING_API_MISS1PARA);
return ;
}
if ( RING_API_ISNUMBER(1) ) {
RING_API_RETNUMBER(sin(RING_API_GETNUMBER(1)));
} else {
RING_API_ERROR(RING_API_BADPARATYPE);
}
}
80.12 Fopen() and Fclose() Functions Implementation
The next code represents the fopen() function implementation using the Ring API and the fopen() C Function.
The function takes two parameters, the first parameter is the file name as string. The second parameter is the mode as
string.
In the file ring_vmfile.h we have some constants to use as the pointer type like
#define RING_VM_POINTER_FILE "file"
#define RING_VM_POINTER_FILEPOS "filepos"
The function implementation in ring_vmfile.c
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void ring_vm_file_fopen ( void *pPointer )
{
FILE *fp ;
if ( RING_API_PARACOUNT != 2 ) {
RING_API_ERROR(RING_API_MISS2PARA);
return ;
}
if ( RING_API_ISSTRING(1) && RING_API_ISSTRING(2) ) {
fp = fopen(RING_API_GETSTRING(1),RING_API_GETSTRING(2));
RING_API_RETCPOINTER(fp,RING_VM_POINTER_FILE);
} else {
RING_API_ERROR(RING_API_BADPARATYPE);
}
}
The next code represents the fclose() function implementation
void ring_vm_file_fclose ( void *pPointer )
{
FILE *fp ;
if ( RING_API_PARACOUNT != 1 ) {
RING_API_ERROR(RING_API_MISS1PARA);
return ;
}
if ( RING_API_ISPOINTER(1) ) {
fp = (FILE *) RING_API_GETCPOINTER(1,RING_VM_POINTER_FILE) ;
if ( fp != NULL ) {
RING_API_RETNUMBER(fclose(fp));
RING_API_SETNULLPOINTER(1);
}
} else {
RING_API_ERROR(RING_API_BADPARATYPE);
}
}
From fopen() and fclose() implementation we learned
1 - how to return C pointer using RING_API_RETCPOINTER() function
2 - how to check if the parameter is a pointer using the RING_API_ISPOINTER() function
3 - how to get C pointer value using the RING_API_GETCPOINTER() function
4 - how to set the C pointer variable (in RingVM) to NULL using the RING_API_SETNULLPOINTER() function
80.13 Ring API - List Functions
In this section we will learn about the list functions provided by the Ring API to create new lists and manipulate the
list items.
List * ring_list_new ( int nSize ) ;
void ring_list_newitem ( List *pList ) ;
Item * ring_list_getitem ( List *pList,int index ) ;
List * ring_list_delete ( List *pList ) ;
void ring_list_deleteitem ( List *pList,int index ) ;
void ring_list_print ( List *pList ) ;
int ring_list_gettype ( List *pList, int index ) ;
void ring_list_setint ( List *pList, int index ,int number ) ;
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void ring_list_addint ( List *pList,int x ) ;
void ring_list_setpointer ( List *pList, int index ,void *pValue ) ;
void ring_list_addpointer ( List *pList,void *pValue ) ;
void ring_list_setfuncpointer ( List *pList, int index ,void (*pFunc)(void *) ) ;
void ring_list_addfuncpointer ( List *pList,void (*pFunc)(void *) ) ;
int ring_list_isfuncpointer ( List *pList, int index ) ;
void ring_list_setdouble ( List *pList, int index ,double number ) ;
void ring_list_adddouble ( List *pList,double x ) ;
void ring_list_setstring ( List *pList, int index ,const char *str ) ;
void ring_list_setstring2 ( List *pList, int index ,const char *str,int nStrSize ) ;
void ring_list_addstring ( List *pList,const char *str ) ;
void ring_list_addstring2 ( List *pList,const char *str,int nStrSize ) ;
List * ring_list_newlist ( List *pList ) ;
List * ring_list_getlist ( List *pList, int index ) ;
void ring_list_setlist ( List *pList, int index ) ;
void ring_list_setactiveitem ( List *pList, Items *pItems, int index ) ;
void ring_list_copy ( List *pNewList, List *pList ) ;
int ring_list_isnumber ( List *pList, int index ) ;
int ring_list_isstring ( List *pList, int index ) ;
int ring_list_islist ( List *pList, int index ) ;
int ring_list_ispointer ( List *pList, int index ) ;
void ring_list_deleteallitems ( List *pList ) ;
void ring_list_insertitem ( List *pList,int x ) ;
void ring_list_insertint ( List *pList,int nPos,int x ) ;
void ring_list_insertdouble ( List *pList,int nPos,double x ) ;
void ring_list_insertpointer ( List *pList,int nPos,void *pValue ) ;
void ring_list_insertstring ( List *pList,int nPos,const char *str ) ;
void ring_list_insertstring2 ( List *pList,int nPos,const char *str,int nStrSize ) ;
void ring_list_insertfuncpointer ( List *pList,int nPos,void (*pFunc)(void *) ) ;
List * ring_list_insertlist ( List *pList,int nPos ) ;
int ring_list_isiteminsidelist ( List *pList,Item *pItem ) ;
int ring_list_findstring ( List *pList,const char *str,int nColumn ) ;
int ring_list_finddouble ( List *pList,double nNum1,int nColumn ) ;
void ring_list_sortnum ( List *pList,int left,int right,int nColumn ) ;
void ring_list_sortstr ( List *pList,int left,int right,int nColumn ) ;
int ring_list_binarysearchnum ( List *pList,double nNum1,int nColumn ) ;
int ring_list_binarysearchstr ( List *pList,const char *cFind,int nColumn ) ;
void ring_list_swap ( List *pList,int x,int y ) ;
double ring_list_getdoublecolumn ( List *pList,int nIndex,int nColumn ) ;
char * ring_list_getstringcolumn ( List *pList,int nIndex,int nColumn ) ;
void ring_list_genarray ( List *pList ) ;
void ring_list_deletearray ( List *pList ) ;
void ring_list_genhashtable ( List *pList ) ;
void ring_list_genhashtable2 ( List *pList ) ;
void ring_list_refcopy ( List *pNewList, List *pList ) ;
void ring_list_clear ( List *pList ) ;
/* Macro */
ring_list_isdouble(pList,index)
ring_list_isint(pList,index)
ring_list_deletelastitem(x)
ring_list_gethashtable(x)
ring_list_getint(pList,index)
ring_list_getpointer(pList,index)
ring_list_getfuncpointer(pList,index)
ring_list_callfuncpointer(pList,index,x)
ring_list_getdouble(pList,index)
ring_list_getstring(pList,index)
ring_list_getstringobject(pList,index)
80.13. Ring API - List Functions 898