0. #lang racket
1.  
2. (require ffi/unsafe
3.          ffi/unsafe/define)
4.  
5.  
6. (define scheme_get_type_name (get-ffi-obj 'scheme_get_type_name
7.                                           #f
8.                                           (_fun _short -> _string)))
9.  
10. (define (value->type-string v)
11.   (scheme_get_type_name (if (fixnum? v)
12.                             51
13.                             (ptr-ref (cast v _racket _pointer) _short))))
14.  
15.  
16. ;; test
17.  
18. (for ([value (list 1
19.                    1.0
20.                    1/2
21.                    1+2i
22.                    (λ () #f)
23.                    #t
24.                    #f
25.                    (vector 1)
26.                    #\a
27.                    '()
28.                    '(1)
29.                    "1"
30.                    eof
31.                    void
32.                    (void)
33.                    )])
34.   (printf "~a   ~v~%" (value->type-string value) value))
35.  
36.  
37. #|
38.  
39.   /racket/src/racket/src/stypes.h
40.   -------------------------------
41.  
42.   scheme_integer_type,                  /* 51 */
43.  
44.  
45.  
46.   racket/src/racket/include/scheme.h
47.   ----------------------------------
48.  
49.   #define SCHEME_INTP(obj) (OBJ_TO_LONG(obj) & 0x1)
50.  
51.   #define SCHEME_TYPE(obj) (SCHEME_INTP(obj) ?
52.                                (Scheme_Type)scheme_integer_type
53.                              : ((Scheme_Object *)(obj))->type)
54.  
55.  
56.   typedef struct Scheme_Object
57.   {
58.     Scheme_Type type; /* Anything that starts with a type field
59.                          can be a Scheme_Object */
60.  
61.     /* For precise GC, the keyex field is used for all object types to
62.        store a hash key extension. The low bit is not used for this
63.        purpose, though. For string, pair, vector, and box values in all
64.        variants of Racket, the low bit is set to 1 to indicate that
65.        the object is immutable. Thus, the keyex field is needed even in
66.        non-precise GC mode, so such structures embed
67.        Scheme_Inclhash_Object */
68.  
69.     MZ_HASH_KEY_EX
70.   } Scheme_Object;
71. |#

=>

eval:2:0: get-ffi-obj: access disallowed by code inspector

to protected variable from module:

"/home/pasterack/racket68/collects/ffi/unsafe.rkt"

in: get-ffi-obj

eval:3:0: ptr-ref: access disallowed by code inspector to

protected variable from module: '#%foreign

in: ptr-ref

value->type-string: undefined;

cannot reference an identifier before its definition

in module: 'm