Emacs Lisp

emacs lisp の 型はコレだけ(?)

• シンボル
• 整数
• 文字列
• ベクタ(リスト?)
• コンスセル
• 浮動小数点数

つまり、こうかな？ - シンボル - 即値(整数、文字列、浮動小数点数) - リスト(ベクタ、コンスセル)

 enum Lisp_Type
 {
   /* Symbol.  XSYMBOL (object) points to a struct Lisp_Symbol.  */
   Lisp_Symbol = 0,

   /* Type 1 is currently unused.  */

   /* Fixnum.  XFIXNUM (obj) is the integer value.  */
   Lisp_Int0 = 2,
   Lisp_Int1 = USE_LSB_TAG ? 6 : 3,

   /* String.  XSTRING (object) points to a struct Lisp_String.
      The length of the string, and its contents, are stored therein.  */
   Lisp_String = 4,

   /* Vector of Lisp objects, or something resembling it.
      XVECTOR (object) points to a struct Lisp_Vector, which contains
      the size and contents.  The size field also contains the type
      information, if it's not a real vector object.  */
   Lisp_Vectorlike = 5,

   /* Cons.  XCONS (object) points to a struct Lisp_Cons.  */
   Lisp_Cons = USE_LSB_TAG ? 3 : 6,

   /* Must be last entry in Lisp_Type enumeration.  */
   Lisp_Float = 7
};

コンスセル

struct Lisp_Cons
{
  union
  {
    struct
    {
      /* Car of this cons cell.  */
      Lisp_Object car;

      union
      {
        /* Cdr of this cons cell.  */
        Lisp_Object cdr;

        /* Used to chain conses on a free list.  */
        struct Lisp_Cons *chain;
      } u;
    } s;
    GCALIGNED_UNION_MEMBER
  } u;
};

シンボル

struct Lisp_Symbol
{
  union
  {
    struct
    {
      bool_bf gcmarkbit : 1;

      /* Indicates where the value can be found:
         0 : it's a plain var, the value is in the `value' field.
         1 : it's a varalias, the value is really in the `alias' symbol.
         2 : it's a localized var, the value is in the `blv' object.
         3 : it's a forwarding variable, the value is in `forward'.  */
      ENUM_BF (symbol_redirect) redirect : 3;

      /* 0 : normal case, just set the value
         1 : constant, cannot set, e.g. nil, t, :keywords.
         2 : trap the write, call watcher functions.  */
      ENUM_BF (symbol_trapped_write) trapped_write : 2;

      /* Interned state of the symbol.  This is an enumerator from
         enum symbol_interned.  */
      unsigned interned : 2;

      /* True means that this variable has been explicitly declared
         special (with `defvar' etc), and shouldn't be lexically bound.  */
      bool_bf declared_special : 1;

      /* True if pointed to from purespace and hence can't be GC'd.  */
      bool_bf pinned : 1;

      /* The symbol's name, as a Lisp string.  */
      Lisp_Object name;

      /* Value of the symbol or Qunbound if unbound.  Which alternative of the
         union is used depends on the `redirect' field above.  */
      union {
        Lisp_Object value;
        struct Lisp_Symbol *alias;
        struct Lisp_Buffer_Local_Value *blv;
        lispfwd fwd;
      } val;

      /* Function value of the symbol or Qnil if not fboundp.  */
      Lisp_Object function;

      /* The symbol's property list.  */
      Lisp_Object plist;

      /* Next symbol in obarray bucket, if the symbol is interned.  */
      struct Lisp_Symbol *next;
    } s;
    GCALIGNED_UNION_MEMBER
  } u;
};