+;;; loadhist.el --- lisp functions for working with feature groups
+;; Copyright (C) 1995 Free Software Foundation, Inc.
+;; Author: Eric S. Raymond <firstname.lastname@example.org>
+;; Keywords: internal, dumped
+;; This file is part of XEmacs.
+;; XEmacs is free software; you can redistribute it and/or modify it
+;; under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; XEmacs is distributed in the hope that it will be useful, but
+;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+;; General Public License for more details.
+;; You should have received a copy of the GNU General Public License
+;; along with XEmacs; see the file COPYING. If not, write to the Free
+;; Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+;;; Synched up with: FSF 20.2.
+;; This file is dumped with XEmacs.
+;; These functions exploit the load-history system variable.
+;; Entry points include `unload-feature', `symbol-file', and `feature-file'.
+(defun symbol-file (sym)
+ "Return the input source from which SYM was loaded.
+This is a file name, or nil if the source was a buffer with no associated file."
+ (interactive "S") ; XEmacs
+ (function (lambda (x) (if (memq sym (cdr x)) (throw 'foundit (car x)))))
+(defun feature-symbols (feature)
+ "Return the file and list of symbols associated with a given FEATURE."
+ (if (member (cons 'provide feature) (cdr x))
+(defun feature-file (feature)
+ "Return the file name from which a given FEATURE was loaded.
+Actually, return the load argument, if any; this is sometimes the name of a
+Lisp file without an extension. If the feature came from an eval-buffer on
+a buffer with no associated file, or an eval-region, return nil."
+ (if (not (featurep feature))
+ (error "%s is not a currently loaded feature" (symbol-name feature))
+ (car (feature-symbols feature))))
+(defun file-provides (file)
+ "Return the list of features provided by FILE."
+ (let ((symbols (cdr (assoc file load-history))) (provides nil))
+ (if (and (consp x) (eq (car x) 'provide))
+ (setq provides (cons (cdr x) provides)))))
+(defun file-requires (file)
+ "Return the list of features required by FILE."
+ (let ((symbols (cdr (assoc file load-history))) (requires nil))
+ (if (and (consp x) (eq (car x) 'require))
+ (setq requires (cons (cdr x) requires)))))
+(defun file-set-intersect (p q)
+ ;; Return the set intersection of two lists
+ (function (lambda (x) (if (memq x q) (setq ret (cons x ret)))))
+(defun file-dependents (file)
+ "Return the list of loaded libraries that depend on FILE.
+This can include FILE itself."
+ (let ((provides (file-provides file)) (dependents nil))
+ (if (file-set-intersect provides (file-requires (car x)))
+ (setq dependents (cons (car x) dependents)))))
+;(defun read-feature (prompt)
+; "Read a feature name \(string\) from the minibuffer,
+;prompting with PROMPT and completing from `features', and
+;return the feature \(symbol\)."
+; (intern (completing-read prompt
+; (mapcar (function (lambda (feature)
+; (list (symbol-name feature))))
+(defun unload-feature (feature &optional force)
+ "Unload the library that provided FEATURE, restoring all its autoloads.
+If the feature is required by any other loaded code, and optional FORCE
+is nil, raise an error."
+ (interactive "SFeature: ")
+ (if (not (featurep feature))
+ (error "%s is not a currently loaded feature" (symbol-name feature)))
+ (let* ((file (feature-file feature))
+ (dependents (delete file (copy-sequence (file-dependents file)))))
+ (error "Loaded libraries %s depend on %s"
+ (prin1-to-string dependents) file)
+ (let* ((flist (feature-symbols feature)) (file (car flist)))
+ (cond ((stringp x) nil)
+ ;; Remove any feature names that this file provided.
+ (if (eq (car x) 'provide)
+ (setq features (delq (cdr x) features))))
+ ((boundp x) (makunbound x))
+ (let ((aload (get x 'autoload)))
+ (if aload (fset x (cons 'autoload aload))))))))
+ ;; Delete the load-history element for this file.
+ (let ((elt (assoc file load-history)))
+ (setq load-history (delq elt load-history)))))
+;;; loadhist.el ends here