/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
#ifndef STACK_H_
#define STACK_H_

/* $Id$ */
/* IDENTIFIER STACK DEFINITIONS */

struct idf;

/*	The identifier stack is implemented as a stack of sets.
	The stack is implemented by a doubly linked list,
	the sets by singly linked lists.
*/

struct stack_level	{
	/* struct stack_level *next; */
	struct stack_level *sl_next;		/* upward link		*/
	struct stack_level *sl_previous;	/* downward link	*/
	struct stack_entry *sl_entry;		/* sideward link	*/
	arith sl_local_offset;		/* @ for first coming object	*/
	arith sl_max_block;		/* maximum size of sub-block	*/
	int sl_level;
};

/* ALLOCDEF "stack_level" 5 */

struct stack_entry	{
	struct stack_entry *next;
	struct idf *se_idf;
};

/* ALLOCDEF "stack_entry" 50 */

extern struct stack_level *local_level;
extern int level;

/*	A new level is added on top of the identifier stack. */
void stack_level(void);
/*	The identifier idf is inserted in the stack on level stl,
	but only if it is not already present at this level.
*/
void stack_idf(struct idf *idf, register struct stack_level *stl);
/*The stack_level corresponding to level lvl is returned.
  The stack should probably be an array, to be extended with
 realloc where needed.
*/
struct stack_level *stack_level_of(int lvl);
/* The top level of the identifier stack is removed. */
void unstack_level(void);
void unstack_world(void);

#ifdef GEN_NM_LIST
void open_name_list(void);
void namelist(char *nm);
#endif /* GEN_NM_LIST */

#endif