Ring/Lessons/Embedding Ring Interpreter in C/C++ Programs

Embedding Ring Interpreter in C/C++ Programs

We can call the Ring interpreter from C/C++ programs using the next functions

	RingState *ring_state_init();
	ring_state_runcode(RingState *pState,const char *cCode);
	ring_state_delete(RingState *pState);

Ring State

The idea is to use the ring_state_init() to create new state for the Ring Interpreter then call the ring_state_runcode() function to execut Ring code using the same state. When we are done, we call the ring_state_delete() to free the memory.

Example:

	#include "ring.h"
	#include "stdlib.h"
	int main(int argc, char *argv[])
	{	
	  RingState *pState = ring_state_init();
	  printf("welcome\n");
	  ring_state_runcode(pState,"see 'hello world from the ring programming language'+nl");
	  ring_state_delete(pState);
	}

Output:

	welcome
	hello world from the ring programming language

Ring State Functions

The Ring API comes with the next functions to create and delete the state. Also we have functions to create new variables and get variables values.

	RingState * ring_state_init ( void ) ;
	RingState * ring_state_delete ( RingState *pRingState ) ;
	void ring_state_runcode ( RingState *pRingState,const char *cStr ) ;
	List * ring_state_findvar ( RingState *pRingState,const char *cStr ) ;
	List * ring_state_newvar ( RingState *pRingState,const char *cStr ) ;
	void ring_state_main ( int argc, char *argv[] ) ;
	void ring_state_runfile ( RingState *pRingState,const char *cFileName ) ;

Ring State Variables

We can create more than one ring state in the same program and we can create and modify variable values.

To get the variable list we can use the ring_state_findvar() function.

To create new variable we can use the ring_state_newvar() function.

Example:

	#include "ring.h"
	#include "stdlib.h"
	
	int main(int argc, char *argv[])
	{
	  List *pList;

  	  RingState *pState = ring_state_init();
	  RingState *pState2 = ring_state_init();

	  printf("welcome\n");
	  ring_state_runcode(pState,"see 'hello world from the ring programming language'+nl");

	  printf("Again from C we will call ring code\n");
	  ring_state_runcode(pState,"for x = 1 to 10 see x + nl next");

	  ring_state_runcode(pState2,"for x = 1 to 5 see x + nl next");

	  printf("Now we will display the x variable value from ring code\n");
	  ring_state_runcode(pState,"see 'x value : ' + x + nl ");
	  ring_state_runcode(pState2,"see 'x value : ' + x + nl ");

	  pList = ring_state_findvar(pState,"x");

	  printf("Printing Ring variable value from C, %.0f\n",
		  	ring_list_getdouble(pList,RING_VAR_VALUE));

	  printf("now we will set the ring variable value from C\n");
	  ring_list_setdouble(pList,RING_VAR_VALUE,20);

	  ring_state_runcode(pState,"see 'x value after update : ' + x + nl ");

	  pList = ring_state_newvar(pState,"v1");
	  ring_list_setdouble(pList,RING_VAR_VALUE,10);	

	  pList = ring_state_newvar(pState,"v2");
	  ring_list_setdouble(pList,RING_VAR_VALUE,20);

	  ring_state_runcode(pState,"see 'v1 + v2 = ' see v1+v2 see nl");

	  ring_state_runcode(pState,"see 'end of test' + nl");

	  ring_state_delete(pState);
	  ring_state_delete(pState2);
	}

Output:

	welcome
	hello world from the ring programming language
	Again from C we will call ring code
	1
	2
	3
	4
	5
	6
	7
	8
	9
	10
	1
	2
	3
	4
	5
	Now we will display the x variable value from ring code
	x value : 11
	x value : 6
	Printing Ring variable value from C, 11
	now we will set the ring variable value from C
	x value after update : 20
	v1 + v2 = 30
	end of test