1 ;;;; REQUIRE, PROVIDE, and friends
3 ;;;; Officially these are deprecated, but in practice they're probably
4 ;;;; even less likely to actually go away than there is to ever be
5 ;;;; another revision of the standard.
7 ;;;; This software is part of the SBCL system. See the README file for
10 ;;;; This software is derived from the CMU CL system, which was
11 ;;;; written at Carnegie Mellon University and released into the
12 ;;;; public domain. The software is in the public domain and is
13 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
14 ;;;; files for more information.
16 (in-package "SB!IMPL")
18 ;;;; exported specials
22 "This is a list of module names that have been loaded into Lisp so far.
23 It is used by PROVIDE and REQUIRE.")
25 (defvar *module-provider-functions
* (list 'module-provide-contrib
)
27 "See function documentation for REQUIRE.")
29 ;;;; PROVIDE and REQUIRE
31 (defun provide (module-name)
33 "Adds a new module name to *MODULES* indicating that it has been loaded.
34 Module-name is a string designator"
35 (pushnew (string module-name
) *modules
* :test
#'string
=)
38 (defvar *requiring
* nil
)
40 (defun require-error (control &rest arguments
)
41 (error 'extension-failure
42 :format-control control
43 :format-arguments arguments
46 '(:sbcl
:variable
*module-provider-functions
*)
47 '(:sbcl
:function require
))))
49 (defun require (module-name &optional pathnames
)
51 "Loads a module, unless it already has been loaded. PATHNAMES, if supplied,
52 is a designator for a list of pathnames to be loaded if the module
53 needs to be. If PATHNAMES is not supplied, functions from the list
54 *MODULE-PROVIDER-FUNCTIONS* are called in order with MODULE-NAME
55 as an argument, until one of them returns non-NIL. User code is
56 responsible for calling PROVIDE to indicate a successful load of the
58 (let ((name (string module-name
)))
59 (when (member name
*requiring
* :test
#'string
=)
60 (require-error "~@<Could not ~S ~A: circularity detected. Please check ~
61 your configuration.~:@>" 'require module-name
))
62 (let ((saved-modules (copy-list *modules
*))
63 (*requiring
* (cons name
*requiring
*)))
64 (unless (member name
*modules
* :test
#'string
=)
66 ;; ambiguity in standard: should we try all pathnames in the
67 ;; list, or should we stop as soon as one of them calls PROVIDE?
68 (dolist (ele (ensure-list pathnames
) t
)
71 (unless (some (lambda (p) (funcall p module-name
))
72 *module-provider-functions
*)
73 (require-error "Don't know how to ~S ~A."
74 'require module-name
)))))
75 (set-difference *modules
* saved-modules
))))
80 (defun module-provide-contrib (name)
82 "Stringify and downcase NAME, then attempt to load the file
84 (let* ((filesys-name (string-downcase (string name
)))
87 (make-pathname :directory
(list :relative
"contrib")
89 (truename (or (sbcl-homedir-pathname)
90 (return-from module-provide-contrib nil
)))))
91 (fasl-path (merge-pathnames
92 (make-pathname :type
*fasl-file-type
*)
94 (lisp-path (merge-pathnames (make-pathname :type
"lisp")
96 ;; KLUDGE: there's a race condition here; the file we probe could
97 ;; be removed by the time we get round to trying to load it.
98 ;; Maybe factor out the logic in the LOAD guesser as to which file
99 ;; was meant, so that we can use it here on open streams instead?
100 (let ((file (or (probe-file fasl-path
)
101 (probe-file unadorned-path
)
102 (probe-file lisp-path
))))
105 (((or style-warning sb
!int
:package-at-variance
) #'muffle-warning
))