stack.h

/*
    STACK

    The stack is represented as a List, i.e. a pointer to a linked
    list of Objs (see objects.h). It creates the illusion of infinite
    memory. You might think that the stack would be necessary because
    the interpreter needs it to run recursive functions. In fact, the
    stack is needed because the evaluator's eval / apply loop is
    itself a recursive procedure.

    Note that the stack is never directly manipulated anywhere.
    Instead, all 'communication' with the stack goes through the stack
    functions save, restore, and clear_stack (plus print_stack in
    print.c). In this way, the stack is like an object and the stack
    functions are like its methods.
*/

/*
    TODO:

*/

#ifndef STACK_GUARD
#define STACK_GUARD

#include <stdio.h>
#include <stdlib.h>

#include "flags.h"
#include "objects.h"
#include "tally.h"

/* stack.c */
void save(Obj reg);
#define restore(reg) _restore(&reg)
void _restore(Obj* reg);

void clear_stack(void);
void initialize_stack(void);

extern List* stack;

#endif