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

struct Int;
struct String;
union Value;

enum Tag { INT, FLOAT, STRING };

typedef union Value (*Lambda)() ;

struct Int {
  enum Tag t;
  int value;
};

struct Float {
  enum Tag t;
  float value;
};

struct String {
  enum Tag t;
  char* value;
};

union Value {
  enum Tag t;
  struct Int i;
  struct Float f;
  struct String s;
} ;

typedef union Value Value;

static Value MakeInt(int n) {
  Value v;
  v.i.t = INT;
  v.i.value = n;
  return v;
}

static Value MakeFloat(float n) {
  Value v;
  v.f.t = FLOAT;
  v.f.value = n;
  return v;
}

static Value MakeString(char* s) {
  Value v;
  v.s.t = STRING;
  v.s.value = s;
  return v;
}


Value sum(Value a, Value b) {
  return MakeInt(a.i.value + b.i.value);
}

Value product(Value a, Value b) {
  return MakeInt(a.i.value * b.i.value);
}

Value difference(Value a, Value b) {
  return MakeInt(a.i.value - b.i.value);
}

Value display(Value v) {
  switch(v.t) {
    case INT:
      printf("%d\n",v.i.value);
      break;
    case FLOAT:
      printf("%f\n",v.f.value);
      break;
    case STRING:
      printf("%s\n",v.s.value);
      break;
  }
  return v;
}

Value equal(Value a, Value b) {
  if (a.t != b.t) return MakeInt(1);
  switch(a.t) {
    case INT: return MakeInt(a.i.value == b.i.value);
    case FLOAT: return MakeInt(a.f.value == b.f.value);
    case STRING: return MakeInt(!strcmp(a.s.value, b.s.value));
  }
  return MakeInt(0);
}