/*
   l_types.c - Procedures that manipulate types in L.
   Samuel A. Rebelsky
   Version 0.1 of 3 March 2007
 */

#include <string.h>
#include <stdlib.h>
#include "l.h"

pair 
make_int(int val)
{
  return allocate_pair(L_INT, (pointer) val);
} /* make_int(int) */

pair 
make_string(char *val)
{
  char *result = (char *) malloc(1 + strlen(val));
  strcpy(result, val);
  return allocate_pair(L_STRING, (pointer) result);
} /* make_string(char *) */

pair 
make_symbol(char *val)
{
  return insert(val);
} /* make_symbol(char *) */

int 
is_nil(pair val)
{
  return L_NIL == val;
} /* is_null(pair) */

int 
is_int(pair val)
{
  return L_INT == val->car;
} /* is_int(pair) */

int 
is_string(pair val)
{
  return L_STRING == val->car;
} /* is_string(pair) */

int 
is_symbol(pair val)
{
  return L_SYMBOL == val->car;
} /* is_symbol(pair) */

int is_pair(pair val)
{
  pointer car = CAR(val);
  return (car != L_STRING) 
         && (car != L_SYMBOL)
         && (car != L_INT);
} /* is_pair(pair) */