LISP generalized lists in C

I want to work with "generalized lists" as in Lisp, say :

((23 () . 2) () ((10))) ; only pointers and integers

So the basic element is a node, a struct with two fields car and cdr.
Each of these fields can contain either a pointer (NULL or a pointer to
another node), or an int.

I want to define the functions cons, car and cdr of Lisp.

I tried this but gcc rejects it :

#include <stdio.h>
#include <stdlib.h>

typedef struct {
object car;
object cdr;
} node;

typedef struct {
int tag; // 0==int, 1==node*
union {
int value;
node *ptr;
} val;
} object;

node* cons(object a, object b) { ...}

Can you help ? Thanks...

JG
.

Relevant Pages

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