Junior Closures Env C Hashtables

main.c

#include <string.h>  /* strcpy */
#include <stdlib.h>  /* malloc */
#include <stdio.h>   /* printf */
#include "uthash.h"

struct closure {
   void* fn;
   struct BoxedValue** env;
};

enum Tag { Bool, Int, Double, Char, String, Closure };
union Value { int b; int v_1; double v_2; char v_3; char* v_4; struct closure* fn; };
struct BoxedValue {
    enum Tag tag;
    union Value value;
};

struct KeyValuePair {
    char name[10];             /* key (string is WITHIN the structure) */
    int id;
    UT_hash_handle hh;         /* makes this structure hashable */
    struct BoxedValue* value;
};

struct BoxedValue* mkBoxedValue(enum Tag tag, union Value value) {
   struct BoxedValue * v = (struct BoxedValue *)malloc(sizeof(struct BoxedValue));
   v->tag = tag;
   v->value = value;
   return v;
}

struct BoxedValue* mkInt(int x) {
   union Value v;
   v.v_1 = x;
   return mkBoxedValue(Int, v);
}

int main(int argc, char *argv[]) {
    const char *names[] = { "numInt", "eqInt", "showInt", NULL };
    struct KeyValuePair *s, *tmp, *users = NULL;

    for (int i = 0; names[i]; ++i) {
        s = (struct KeyValuePair *)malloc(sizeof *s);
        strcpy(s->name, names[i]);
        s->value = mkInt(i);
        HASH_ADD_STR(users, name, s);
    }

    HASH_FIND_STR(users, "eqInt", s);
    if (s) printf("eqInt's id is %d\n", s->value->value.v_1);

    /* free the hash table contents */
    HASH_ITER(hh, users, s, tmp) {
      HASH_DEL(users, s);
      free(s);
    }
    return 0;
}