Playing with SymPy design in C

From SymPy

This is playground for SymPy like design in C. <source lang="c">

1. include "stdlib.h"
2. include "stdio.h"

//----------------------- basic ---------------------------------

typedef struct _basic {

   void (*print)();

   struct _basic *args;
   int nargs;

} basic;

void basic_print(basic *b) {

   if (b->nargs != 0)
   {
       printf("basic_print nargs\n");
   }
   else
       printf("basic_print\n");

}

void basic_init(basic *b) {

   b->print = basic_print;
   b->nargs = 0;

}

basic *basic_new() {

   basic *b;
   b = malloc(sizeof(basic));
   basic_init(b);
   return b;

}

//------------------------ add -------------------------------------------

typedef struct {

   basic super;

   int i,j;

} add;

void add_print(add *p) {

   printf("add_print %d %d\n", p->i, p->j);

}

basic *add_new(int a, int b) {

   add *p;
   p = malloc(sizeof(add));
   basic_init((basic *)p);
   p->super.print = add_print;
   p->super.nargs = 1;
   p->i = a;
   p->j = b;
   return (basic *)p;

}

// ------------------------------------------------------------

int main() {

   basic *b;
   b = basic_new();
   b->print(b);
   b = add_new(1, 2);
   b->print(b);
   printf("OK");
   return 0;

} </source>

output: <source lang="bash"> $ ./basic basic_print add_print 1 2 </source>