elk/include/object.h

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/* The Scheme object representation, and a few other important
* data types.
*/
typedef struct {
unsigned long data;
int tag;
} Object;
#define FIXBITS (8 * sizeof(int))
#define SIGNBIT ((unsigned)1 << (FIXBITS-1))
#define CONSTBIT 1
#define TYPEBITS (8 * sizeof(int) - 1)
#define MAX_TYPE ((1 << TYPEBITS) - 1)
#define UFIXNUM_FITS(i) (((i) & SIGNBIT) == 0)
#define FIXNUM_FITS(i) 1
#define TYPE(x) ((x).tag >> 1)
#define FIXNUM(x) ((int)(x).data)
#define CHAR(x) ((int)(x).data)
#define POINTER(x) ((x).data)
#define SETPOINTER(x,p) ((x).data = (unsigned long)(p))
#define SET(x,t,p) ((x).tag = (int)t << 1, (x).data = (unsigned long)(p))
#define ISCONST(x) ((x).tag & CONSTBIT)
#define SETCONST(x) ((x).tag |= CONSTBIT)
#define EQ(x,y) ((x).data == (y).data && (x).tag == (y).tag)
/* GC related macros:
*/
#define WAS_FORWARDED(obj) (TYPE(*(Object *)POINTER(obj)) == T_Broken_Heart)
#define UPDATE_OBJ(obj) SETPOINTER(obj, POINTER(*(Object *)POINTER(obj)))
#ifdef GENERATIONAL_GC
typedef int gcspace_t; /* type used for space and type arrays */
typedef unsigned long gcptr_t; /* type used for pointers */
typedef unsigned long pageno_t; /* type used for page numbers */
typedef unsigned long addrarith_t; /* type used for address arithmetic */
extern gcspace_t *space;
extern gcspace_t current_space;
C_LINKAGE_BEGIN
extern Visit P_((Object*)); /* required for REVIVE_OBJ below */
C_LINKAGE_END
# ifdef ARRAY_BROKEN
extern pageno_t pagebase;
# else
# define pagebase ((pageno_t)0)
# endif
# define PAGEBYTES 512
# define PAGE_TO_OBJ(p) ((Object *) (((p) + pagebase) * PAGEBYTES))
# define OBJ_TO_PAGE(p) ((((gcptr_t)POINTER(p)) / PAGEBYTES) - pagebase)
# define STABLE(x) ((~space[(x)]) & 1)
# define MAKEOBJ(o,t,p) (SET(o, t, p))
# define IS_ALIVE(obj) ((WAS_FORWARDED(obj)) || \
(STABLE(OBJ_TO_PAGE(obj))) || \
(space[OBJ_TO_PAGE(obj)] == current_space))
# define REVIVE_OBJ(obj) Visit (&obj);
#else
# define IS_ALIVE(obj) WAS_FORWARDED(obj)
# define REVIVE_OBJ(obj)
#endif
/* Fixed types. Cannot use enum, because the set of types is extensible:
*/
#define T_Fixnum 0 /* Must be 0 */
#define T_Bignum 1
#define T_Flonum 2
#define T_Null 3 /* empty list */
#define T_Boolean 4 /* #t (1) and #f (0) */
#define T_Unbound 5 /* only used internally */
#define T_Special 6 /* only used internally */
#define T_Character 7
#define T_Symbol 8
#define T_Pair 9
#define T_Environment 10 /* A pair */
#define T_String 11
#define T_Vector 12
#define T_Primitive 13 /* Primitive procedure */
#define T_Compound 14 /* Compound procedure */
#define T_Control_Point 15
#define T_Promise 16 /* Result of (delay expression) */
#define T_Port 17
#define T_End_Of_File 18
#define T_Autoload 19
#define T_Macro 20
#define T_Broken_Heart 21 /* only used internally */
#ifdef GENERATIONAL_GC
# define T_Align_8Byte 22 /* only used internally */
# define T_Freespace 23 /* only used internally */
#endif
#define BIGNUM(x) ((struct S_Bignum *)POINTER(x))
#define FLONUM(x) ((struct S_Flonum *)POINTER(x))
#define STRING(x) ((struct S_String *)POINTER(x))
#define VECTOR(x) ((struct S_Vector *)POINTER(x))
#define SYMBOL(x) ((struct S_Symbol *)POINTER(x))
#define PAIR(x) ((struct S_Pair *)POINTER(x))
#define PRIM(x) ((struct S_Primitive *)POINTER(x))
#define COMPOUND(x) ((struct S_Compound *)POINTER(x))
#define CONTROL(x) ((struct S_Control *)POINTER(x))
#define PROMISE(x) ((struct S_Promise *)POINTER(x))
#define PORT(x) ((struct S_Port *)POINTER(x))
#define AUTOLOAD(x) ((struct S_Autoload *)POINTER(x))
#define MACRO(x) ((struct S_Macro *)POINTER(x))
typedef unsigned short gran_t; /* Granularity of bignums */
struct S_Bignum {
Object minusp;
unsigned size; /* Number of ushorts allocated */
unsigned usize; /* Number of ushorts actually used */
gran_t data[1]; /* Data, lsw first */
};
struct S_Flonum {
Object tag; /* Each S_Foo must start with an Object */
double val;
};
struct S_Symbol {
Object value;
Object next;
Object name; /* A string */
Object plist;
};
struct S_Pair {
Object car, cdr;
};
struct S_String {
Object tag;
int size;
char data[1];
};
struct S_Vector {
Object tag;
int size;
Object data[1];
};
enum discipline { EVAL, NOEVAL, VARARGS };
struct S_Primitive {
Object tag;
Object (*fun) P_((ELLIPSIS));
const char *name;
int minargs;
int maxargs; /* Or MANY */
enum discipline disc;
};
#define MANY 100
struct S_Compound {
Object closure; /* (lambda (args) form ...) */
Object env; /* Procedure's environment */
int min_args, max_args;
int numforms;
Object name;
};
typedef struct wind {
struct wind *next, *prev;
Object inout; /* Pair of thunks */
} WIND;
typedef struct funct {
struct funct *next;
char *name;
void (*func) P_((void));
} FUNCT;
typedef struct gcnode {
struct gcnode *next;
int gclen;
Object *gcobj;
} GCNODE;
typedef struct mem_node {
struct mem_node *next;
unsigned len;
unsigned long refcnt;
} MEM_NODE;
#if defined(vax) || defined(__vax__)
typedef int jmp_buf[17];
#else
# include <setjmp.h>
#endif
struct S_Control {
Object env;
GCNODE *gclist;
MEM_NODE *memlist;
Object memsave; /* string */
Object gcsave; /* vector */
WIND *firstwind, *lastwind;
int tailcall;
unsigned delta;
#ifdef GENERATIONAL_GC
int reloc;
#endif
jmp_buf j;
int size;
unsigned long intrlevel;
char stack[1]; /* must be word aligned */
};
struct S_Promise {
Object env;
Object thunk;
int done;
};
struct S_Port {
Object name; /* string */
short flags;
char unread;
int ptr;
FILE *file;
unsigned lno;
int (*closefun) P_((FILE*));
};
#define P_OPEN 1 /* flags */
#define P_INPUT 2
#define P_STRING 4
#define P_UNREAD 8
#define P_BIDIR 16
#define IS_INPUT(port) (PORT(port)->flags & (P_INPUT|P_BIDIR))
#define IS_OUTPUT(port) ((PORT(port)->flags & (P_INPUT|P_BIDIR)) != P_INPUT)
struct S_Autoload {
Object files;
Object env;
};
struct S_Macro {
Object body;
int min_args, max_args;
Object name;
};
/* "size" is called with one object and returns the size of the object.
* If "size" is NOFUNC, then "const_size" is taken instead.
* "eqv" and "equal" are called with two objects and return 0 or 1.
* NOFUNC may be passed instead (then eqv and equal always return #f).
* "print" is called with an object, a port, a flag indicating whether
* the object is to be printed "raw" (a la display), the print-depth,
* and the print-length.
* "visit" is called with a pointer to an object and a function.
* For each component of the object, the function must be called with
* a pointer to the component. NOFUNC may be supplied.
*/
typedef struct {
int haspointer;
const char *name;
int (*size) P_((Object));
int const_size;
int (*eqv) P_((Object, Object));
int (*equal) P_((Object, Object));
int (*print) P_((Object, Object, int, int, int));
int (*visit) P_((Object*, int (*)(Object*)));
} TYPEDESCR;
#ifdef ELK_USE_PROTOTYPES
# define NOFUNC 0
#else
# define NOFUNC ((int (*)())0)
#endif
typedef struct sym {
struct sym *next;
char *name;
unsigned long value;
} SYM;
typedef struct {
SYM *first;
char *strings;
} SYMTAB;
typedef struct {
char *name;
int type;
} SYMPREFIX;
#define PR_EXTENSION 0 /* Elk extension initializers/finalizers */
#define PR_CONSTRUCTOR 1 /* C++ static constructors/destructors */
/* PFO, GENERIC, and MATCHFUN exist for backwards compatibility
*/
typedef Object (*PFO) P_((Object));
typedef int (*MATCHFUN) P_((ELLIPSIS));
#define GENERIC char*
typedef struct weak_node {
struct weak_node *next;
Object obj;
PFO term;
GENERIC group;
char flags;
} WEAK_NODE;
/* flags */
#define WK_LEADER 1
typedef struct {
char *name;
unsigned long val;
} SYMDESCR;
/* Function that can be registered as a reader by Define_Reader():
*/
typedef Object (*READFUN) P_((Object, int, int));