reorder stuffs and update comments

src/ma_obj.h

@@ -8,141 +8,165 @@
 
 #include "ma_conf.h"
 
-/*
- * The struct `Class` is also an object which
- * is collectable.
- */
-#define Class
-#define Bool
-#define Num
-#define Str
-#define Range
-#define Array
-#define Map
-#define Set
-#define MSet
-#define Bag
-#define MBag
-#define Fun
-#define GFun
-#define Ma
-#define Work
-#define Chan
-#define Regex
-#define Socket
-#define Pipe
-#define File
-#define Dir
-#define Proc
-#define Sys
-#define Date
-#define Term
+/* Vary type 't' with the variant bits 'v' */
+#define vary(t,v)  ((t) | (v << 5))
+
+#define with_variant(v)     (v.type)
+#define without_variant(v)  (v.type & (~OBJ_BITS))
+#define check_type(v,t)     (without_variant(v) == t)
+#define check_vartype(v,t)  (with_variant(v) == t)
+
+#if defined(MA_NAN_TAGGING)
 
 /*
- * Representing a value
+ * TODO
  */
-#if defined(MA_NAN_TAGGING)
+typedef uint64_t Value;
 
-#else 
 
-/* Different possible types of values */
-#define TYPE_NIL   0
-#define TYPE_BOOL  1
-#define TYPE_NUM   2
-#define TYPE_CFUNC 3
+#else 
 
 /*
  * $val: the value itself.
- *    $n: Maat's representation of a value(configured at 'ma_conf.h').
- *    $obj: pointer to an object, value is an object.
+ *   $n: Maat's representation of a value(configured at 'ma_conf.h').
+ *   $obj: pointer to an object, value is an object.
  *
- *    The below attributes are used to extend Maat code with C/C++:
+ *   The below attributes are used to extend Maat code with C/C++:
  *
- *    $p: pointer to C-class attributes('struct's).
- *    $f: pointer to a C functions, either represent a method to a
- *    C-class or just a standalone function.
+ *   $cdata: pointer to C-class attributes('struct's).
+ *   $f: pointer to a C functions, either represent a cdata's method
+ *   or just a standalone function.
  *
  * $type: determines val's type, this variable already gather all what is
  * necessary to represent booleans and nils values. It is segmented into
  * three parts. Bits distribution:
  *
- * - bits 0-4
- *   to represent the different types of values except as objects. 'val'
- *   is an object when bits 5-6 are set to 1, if 'val' is an object then
- *   bits 0-4 determine its object's type. This gives us a maximum of 32
- *   objects which is sufficient enough.
+ * - bits 0-4:
+ *   to represent the different types of values except for object values
+ *   which is determined by the MSB. if 'val' is an object then bits 0-4
+ *   determine its object's type. This gives us a maximum of 32 objects
+ *   which is sufficient enough.
  *
- * - bits 5-6
+ * - bits 5-6:
  *   to represent variants of certain TYPE_* types. You can have at most
- *   2 variants since bits 5-6 all set to one tell 'val' is an object.
+ *   3 variants which is sufficient enough.
  *
- * - bit 7
- *   Whether 'val' is collectable(1) or not(0).
+ * - bit 7: Whether 'val' is(1) an object or not(0)
  */
 typedef struct {
    Ubyte type;
    union {
       struct Header *obj;
       Num n;
-      void *p;
       CFunc f;
+      void *cdata;
    } val;
 } Value;
 
 
-#define OBJ_BITS  (0b11 << 5)
-
-/* Vary type 't' with the variant bits 'v' */
-#define vary(t,v)  ((t) | (v << 5))
+/* All posible standard types of values (TYPE_OBJ marked by the MSB) */
+#define TYPE_NIL    0
+#define TYPE_BOOL   1
+#define TYPE_NUM    2
+#define TYPE_CFUNC  3
+#define TYPE_CDATA  4
 
-#define with_variant(v)     (v.type)
-#define without_variant(v)  (v.type & (~OBJ_BITS))
-#define check_type(v,t)     (without_variant(v) == t)
-#define check_vartype(v,t)  (with_variant(v) == t)
+#define OBJ_BIT  (0b1 << 7)
 
-#define is_obj(v)    ((with_variant(v) & OBJ_BITS) == OBJ_BITS)
+#define is_obj(v)    (with_variant(v) & OBJ_BIT)
 #define is_num(v)    check_type(v,TYPE_NUM)
 #define is_nil(v)    check_type(v,TYPE_NIL)
 #define is_bool(v)   check_type(v,TYPE_BOOL)
 #define is_cfunc(v)  check_type(v,TYPE_CFUNC)
+#define is_cdata(v)  check_type(v,TYPE_CDATA)
 
-/* Define the 'nil' value/type with its variants */
-#define NIL     vary(TYPE_NIL, 0)
-#define KEYNIL  vary(TYPE_NIL, 1)
-#define VALNIL  vary(TYPE_NIL, 2)
+#define is_collectable(v)  is_obj(v)
 
-#define is_strict_nil(v)  check_vartype(v,NIL)
+#define as_bool(v)   (is_true(v))
+#define as_num(v)    (v.val.n)
+#define as_obj(v)    (v.val.obj)
+#define as_cfunc(v)  (v.val.f)
+#define as_cdata(v)  (v.val.cdata)
 
+#define type(v)  with_variant(v)
 
-/* Define the boolean value/type with its Variants */
-#define BOOL   vary(TYPE_BOOL, 0)
-#define TRUE   vary(TYPE_BOOL, 1)
-#define FALSE  vary(TYPE_BOOL, 2)
+/*
+ * real type, real in the sense that we don't need to know whether or
+ * not internally it is an object.
+ */
+#define rtype(v)  (ma_likely(is_obj(v)) ? as_obj(v).type : type(v))
 
-#define is_bool(v)   check_type(v,TYPE_BOOL)
-#define is_false(v)  check_vartype(to_bool(v),FALSE)
-#define is_true(v)   check_vartype(to_bool(v),TRUE)
+/*
+ * Define the 'nil' type, its variants, and singleton values.
+ *
+ * TYPEV_FREE: this nil variant differentiates a key whose corresponding
+ * value is a user-perceived 'nil' from a free position in a hash table.
+ *
+ * TYPEV_ABSKEY: when indexing a hash table, return this value when key
+ * isn't found.
+ */
+#define TYPEV_FREE    vary(TYPE_NIL, 1)
+#define TYPEV_ABSKEY  vary(TYPE_NIL, 2)
 
-#define to_bool  (is_bool(v) ? v : coerce_to_bool(v))
+#define FREE    (Value){ TYPEV_FREE,   { 0 } }
+#define ABSKEY  (Value){ TYPEV_ABSKEY, { 0 } }
+
+#define is_strict_nil(v)  check_vartype(v,NIL)
+#define is_free(v)        check_vartype(v,TYPEV_NILKEY)
+#define is_abskey(v)      check_vartype(v,TYPEV_ABSKEY)
 
-#define as_bool(v)   (is_true(v))
-#define as_num(v)    (v.val.n)
-#define as_obj(v)    (v.val.obj)
-#define as_cfunc(v)  (v.val.f)
 
-#define COLLECTABLE_BIT    (0b1 << 7)
-#define is_collectable(v)  (with_variant(v) & COLLECTABLE_BIT)
+/* Define boolean type variants with its singleton values */
+#define TYPEV_TRUE   vary(TYPE_BOOL, 1)
+#define TYPEV_FALSE  vary(TYPE_BOOL, 2)
+
+#define BOOL   (Value){ TYPE_BOOL,   { 0 } }
+#define TRUE   (Value){ TYPEV_TRUE,  { 0 } }
+#define FALSE  (Value){ TYPEV_FALSE, { 0 } }
+
+#define is_bool(v)   check_type(v,TYPE_BOOL)
+#define is_false(v)  check_vartype(to_bool(v),TYPEV_FALSE)
+#define is_true(v)   check_vartype(to_bool(v),TYPEV_TRUE)
+
+#define to_bool  (ma_likely(is_bool(v)) ? v : coerce_to_bool(v))
 
 #endif
 
+/*
+ *
+ */
+#define Class  5
+#define Bool   6
+#define Num    7
+#define Str    8
+#define Range  9
+#define Array  10
+#define Map    11
+#define Set    12 /* variant: MSet */
+#define Bag    12 /* variant: MBag */
+#define Fun    11 /* variant: GFun */
+#define Ma     12 /* variant: Work */
+#define Rbq    13 /* variant: Chan, Schedq */
+#define Regex  15
+#define Socket 16
+#define Pipe   17
+#define File   18
+#define Dir    19
+#define Proc   20
+#define Sys    21
+#define Date   22
+#define Term   23
+
 /*
  * struct Header inherited by all objects
  * $type: type of the object
- * $Class: the object's class
+ * $marked: flag to mark the object during gc
+ * $class: the object's class
  * $next: next obj, to keep track of all objects
  */
 typedef struct Header {
    Ubyte type;
+   Ubyte mark;
    struct Class *class;
    struct Header *next;
 } Header;