src/code/primordial-type.lisp

   1 ;;;; This software is part of the SBCL system. See the README file for
   2 ;;;; more information.
   3 ;;;;
   4 ;;;; This software is derived from the CMU CL system, which was
   5 ;;;; written at Carnegie Mellon University and released into the
   6 ;;;; public domain. The software is in the public domain and is
   7 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
   8 ;;;; files for more information.
   9
  10 (in-package "SB!KERNEL")
  11
  12 ;;; Has the type system been properly initialized? (I.e. is it OK to
  13 ;;; use it?)
  14 (!defglobal *type-system-initialized* nil)
  15
  16 ;; These are set by cold-init-forms in 'late-type' (look for "macrolet frob").
  17 ;; It is a requirement of the type machinery that there be
  18 ;; exactly one instance of each of these, which is to say,
  19 ;; any type named T is exactly EQ to *UNIVERSAL-TYPE*, etc.
  20 (defglobal *wild-type* -1)
  21 (defglobal *empty-type* -1)
  22 (defglobal *universal-type* -1)
  23 (defglobal *instance-type* -1)
  24 (defglobal *funcallable-instance-type* -1)
  25 (defglobal *extended-sequence-type* -1)
  26
  27 ;; Unlike the above, this one is not a NAMED-TYPE, and as such
  28 ;; does not have to be a singleton, but it improves efficiency.
  29 ;; (Except that we never really need it for anything)
  30 (defglobal *universal-fun-type* -1)
  31
  32 ;; These need not be singletons, but again it is more efficient
  33 ;; when there is only a single instance of each.
  34 (defglobal *cons-t-t-type* -1)
  35 (defglobal *null-type* -1)
  36 (defglobal *boolean-type* -1)
  37
  38 ;; This one is used when parsing (SATISFIES KEYWORDP)
  39 ;; so that simplifications can be made whe computing intersections,
  40 ;; without which we would see this kind of "empty-type in disguise"
  41 ;;   (AND (SATISFIES KEYWORDP) CONS)
  42 ;; This isn't *keyword-type* because KEYWORD is implemented
  43 ;; as the intersection of SYMBOL and (SATISFIES KEYWORDP)
  44 ;; We could also intern the KEYWORD type but that would require
  45 ;; hacking the INTERSECTION logic.
  46 (defglobal *satisfies-keywordp-type* -1)
  47
  48 ;; Here too I discovered more than 1000 instances in a particular
  49 ;; Lisp image, when really this is *EMPTY-TYPE*.
  50 ;;  (AND (SATISFIES LEGAL-FUN-NAME-P) (SIMPLE-ARRAY CHARACTER (*)))
  51 (defglobal *fun-name-type* -1)
  52
  53 ;;; a vector that maps type codes to layouts, used for quickly finding
  54 ;;; the layouts of built-in classes
  55 (defglobal **built-in-class-codes** #()) ; initialized in cold load
  56 (declaim (type simple-vector **built-in-class-codes**))