#ifndef __PF_STACK__
#define __PF_STACK__

/**
   @file stack.h
   @brief Basic stack operations

   All the pf_stack_ functions perform reference count management. 
   As opposed to pf_list_ and pf_tree_ operations, which work on the list/tree structure only.

   A stack is treated as a tree (all embedded lists are branches), and all data is owned
   by the stack. Note that if you create objects that are not referenced on the stacks
   (return/data/dictionary stacks), you explicitly need to manage them yourself.

*/

void pf_stack_free(pf_stack_t *s);
void pf_stack_clear(pf_stack_t *s);

/* forth words. not all the words in forth.c are declared here.
   if you need more (i.e. for extension modules), this is the place to add declarations. */

pf_error_t pf_stack_drop(pf_stack_t *s);
pf_error_t pf_stack_swap(pf_stack_t *s);

/* some util stuff */
pf_stack_t *pf_stack_new(void);

void pf_stack_free(pf_stack_t *s);
void pf_stack_clear(pf_stack_t *s);

/* move between two stacks*/
static inline void pf_stack_move(pf_stack_t *from, pf_stack_t *to) {
    pf_list_push_atom(to, pf_list_pop_atom(from));
}

static inline pf_error_t pf_check_atom(pf_atom_t *s, int n){
    while (n--) 
	if (!(s = pf_atom_next(s))) return e_underflow;
    return e_ok;
}








#endif