/*
 * File:
 *   ilist.c
 * Authors:
 *   CSC195 2003S
 * Summary:
 *   Implementation of important stuff related to
 *   Scheme-like lists of integers.
 */

#include "ilist.h"

/* Simple wrapper for clarity. */
ilist 
inull() {
  return (ilist) NULL;
} /* inull() */

int 
iIsEmpty(ilist il) {
  return (il == (ilist) NULL);
} /* iIsEmpty(ilist) */

/* May return null if there's not enough space in
   memory for a new pair. */
ilist 
icons(int head, ilist tail) {
  ilist newlist = (ilist) malloc(sizeof(inode));
  if (!newlist) return newlist;
  newlist->val = head;
  newlist->next = tail;
  return newlist;
} /* incons(int, ilist) */

int icar(ilist il) {
  /* Error checking? */
  return ilist->val;
}

ilist icdr(ilist il) {
  return ilist->next;
}