1 ;;;; that part of DEFTYPE which runs within the compiler itself
3 ;;;; This software is part of the SBCL system. See the README file for
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
12 (in-package "SB!IMPL")
14 (defun %compiler-deftype (name expander &optional doc)
15 (ecase (info :type :kind name)
17 (when *type-system-initialized*
18 (error "illegal to redefine standard type: ~S" name)))
20 (warn "The class ~S is being redefined to be a DEFTYPE." name)
21 (undefine-structure (layout-info (class-layout (sb!xc:find-class name))))
22 (setf (class-cell-class (find-class-cell name)) nil)
23 (setf (info :type :compiler-layout name) nil)
24 (setf (info :type :kind name) :defined))
26 ;; Note: It would be nice to warn here when a type is being
27 ;; incompatibly redefined, but it's hard to tell, since type
28 ;; expanders are often function objects which can't easily be
29 ;; compared for equivalence. And just warning on redefinition
30 ;; isn't good, since DEFTYPE necessarily does its thing once at
31 ;; compile time and again at load time, so that it's very common
32 ;; and normal for types to be defined twice. So since there
33 ;; doesn't seem to be anything simple and obvious to do, and
34 ;; since mistakenly redefining a type isn't a common error
35 ;; anyway, we just don't worry about trying to warn about it.
38 (setf (info :type :kind name) :defined)))
39 (setf (info :type :expander name) expander)
41 (setf (fdocumentation name 'type) doc))
42 ;; ### Bootstrap hack -- we need to define types before %NOTE-TYPE-DEFINED
43 ;; is defined. (FIXME: Do we still need to do this? -- WHN 19990310)
44 (if (fboundp 'sb!c::%note-type-defined)
45 (sb!c::%note-type-defined name)
46 (warn "defining type before %NOTE-TYPE-DEFINED is defined"))