/**
  * Copyright (c): Uwe Schmidt, FH Wedel
  *
  * You may study, modify and distribute this source code
  * FOR NON-COMMERCIAL PURPOSES ONLY.
  * This copyright message has to remain unchanged.
  *
  * Note that this document is provided 'as is',
  * WITHOUT WARRANTY of any kind either expressed or implied.
  */

#ifndef RING_H__
#define RING_H__ 1

/*--------------------*/

/* lists implemented as simple ring */

typedef char *Element;

/*--------------------*/

typedef struct Node *List;

struct Node
{
  Element info;
  List next;
};


/*--------------------*/

extern List mkEmptyList (void);
extern List mkOne (Element e);

extern int isEmptyList (List l);

extern unsigned int length (List l);

extern Element head (List l);
extern Element at (List l, unsigned int i);


extern List tail (List l);
extern List cons (Element e, List l);
extern List append (List l, Element e);
extern List concat (List l1, List l2);

extern List insertAt (List l, unsigned int i, Element e);
extern List removeAt (List l, unsigned int i);
extern List splitAt (List l, unsigned int i, List * rest);

/*--------------------*/

#endif