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emacs/lisp/libc.el
1997-05-26 21:41:50 +00:00

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;;; libc.el -- lookup C symbols in the GNU C Library Reference Manual.
;; Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
;;; Author: Ralph Schleicher <rs@purple.UL.BaWue.DE>
;;; Keywords: local c info
;; This file is part of GNU Emacs.
;; GNU Emacs 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)
;; any later version.
;; GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;; This code has a long history. It started as a minor
;; mode for C mode. This era ended with the release of version 2
;; of the GNU C Library in 1997. The code was therefore rewritten
;; more or less from scratch so that all lookups are performed via
;; indices. Not finding an existing symbol in an index means that
;; there is an error in the manual. Long missed features like a
;; separate input history, symbol name completion in the mini-buffer,
;; highlighting of looked up symbol names in the Info buffer, and
;; implicitly prepending `struct', `union' or `enum' to data types
;; were added in this phase too.
;;; Code:
(require 'info)
(defvar libc-info-file-name "libc"
"Basename of the Info file of the GNU C Library Reference Manual.")
(defvar libc-highlight-face 'highlight
"*Face for highlighting looked up symbol names in the Info buffer.
`nil' disables highlighting.")
(defvar libc-highlight-overlay nil
"Overlay object used for highlighting.")
(defconst libc-symbol-completions nil
"Alist of documented C symbols.")
(defconst libc-file-completions nil
"Alist of documented programs or files.")
(defvar libc-history nil
"History of previous input lines.")
;;;###autoload
(defun libc-describe-symbol (symbol-name)
"Display the documentation of a C symbol in another window.
SYMBOL-NAME must be documented in the GNU C Library Reference Manual.
If called interactively, SYMBOL-NAME will be read from the mini-buffer.
Optional prefix argument means insert the default symbol (if any) into
the mini-buffer so that it can be edited. The default symbol is the
one found at point.
If SYMBOL-NAME is a public function, variable, or data type of the GNU
C Library but `libc-describe-symbol' fails to display it's documentation,
then you have found a bug in the manual. Please report that to the mail
address `bug-glibc-manual@prep.ai.mit.edu' so that it can be fixed."
(interactive
(let* ((completion-ignore-case nil)
(enable-recursive-minibuffers t)
(symbol (libc-symbol-at-point))
(value (completing-read
(if symbol
(format "Describe symbol (default %s): " symbol)
(format "Describe symbol: "))
libc-symbol-completions nil nil
(and current-prefix-arg symbol) 'libc-history)))
(list (if (equal value "") symbol value))))
(or (assoc symbol-name libc-symbol-completions)
(error "Not documented as a C symbol: %s" (or symbol-name "")))
(or (libc-lookup-function symbol-name)
(libc-lookup-variable symbol-name)
(libc-lookup-type symbol-name)))
;;;###autoload
(defun libc-describe-file (file-name)
"Display the documentation of a program or file in another window.
FILE-NAME must be documented in the GNU C Library Reference Manual."
(interactive
(let* ((completion-ignore-case nil)
(enable-recursive-minibuffers t))
(list (completing-read
"Describe program or file: "
libc-file-completions nil nil nil 'libc-history))))
(or (assoc file-name libc-file-completions)
(error "Not documented as a program or file: %s" (or file-name "")))
(libc-lookup-file file-name))
;;;###autoload
(defun libc-search (regexp &optional arg)
"Search in the GNU C Library Reference Manual for REGEXP.
Prefix argument means search should ignore case."
(interactive "sSearch `libc.info' for regexp: \nP")
(or (get-buffer "*info*")
(save-window-excursion
(info)))
(switch-to-buffer-other-window "*info*")
(Info-goto-node (concat "(" libc-info-file-name ")"))
(let ((case-fold-search arg))
(Info-search regexp)))
(defun libc-make-completion-alist (info-nodes &optional regexp)
"Create a unique alist from all menu items in the Info nodes INFO-NODES
of the GNU C Reference Manual.
Optional second argument REGEXP means include only menu items matching the
regular expression REGEXP."
(condition-case nil
(let (completions item)
(save-window-excursion
(info libc-info-file-name)
(while info-nodes
(Info-goto-node (car info-nodes))
(goto-char (point-min))
(and (search-forward "\n* Menu:" nil t)
(while (re-search-forward "\n\\* \\([^:\t\n]*\\):" nil t)
(setq item (buffer-substring
(match-beginning 1) (match-end 1)))
(and (not (assoc item completions))
(if regexp (string-match regexp item) t)
(setq completions (cons (cons item nil)
completions)))))
(setq info-nodes (cdr info-nodes)))
(Info-directory))
completions)
(error nil)))
(defun libc-after-manual-update ()
"This function must only be called after a new version of the
GNU C Library Reference Manual was installed on your system."
(setq libc-symbol-completions (libc-make-completion-alist
'("Function Index"
"Variable Index"
"Type Index"))
libc-file-completions (libc-make-completion-alist
'("File Index") "^[^ \t]+$")))
(or (and libc-symbol-completions
libc-file-completions)
(libc-after-manual-update))
(defun libc-symbol-at-point ()
"Get the C symbol at point."
(condition-case nil
(save-excursion
(backward-sexp)
(let ((start (point))
prefix name)
;; Test for a leading `struct', `union', or `enum' keyword
;; but ignore names like `foo_struct'.
(setq prefix (and (< (skip-chars-backward " \t\n") 0)
(< (skip-chars-backward "_a-zA-Z0-9") 0)
(looking-at "\\(struct\\|union\\|enum\\)\\s ")
(concat (buffer-substring
(match-beginning 1) (match-end 1))
" ")))
(goto-char start)
(and (looking-at "[_a-zA-Z][_a-zA-Z0-9]*")
(setq name (buffer-substring
(match-beginning 0) (match-end 0))))
;; Caveat! Look forward if point is at `struct' etc.
(and (not prefix)
(or (string-equal name "struct")
(string-equal name "union")
(string-equal name "enum"))
(looking-at "[a-z]+\\s +\\([_a-zA-Z][_a-zA-Z0-9]*\\)")
(setq prefix (concat name " ")
name (buffer-substring
(match-beginning 1) (match-end 1))))
(and (or prefix name)
(concat prefix name))))
(error nil)))
(defun libc-lookup-function (function)
(libc-search-index "Function Index" function
"^[ \t]+- \\(Function\\|Macro\\): .*\\<" "\\>"))
(defun libc-lookup-variable (variable)
(libc-search-index "Variable Index" variable
"^[ \t]+- \\(Variable\\|Macro\\): .*\\<" "\\>"))
(defun libc-lookup-type (data-type)
(libc-search-index "Type Index" data-type
"^[ \t]+- Data Type: \\<" "\\>"))
(defun libc-lookup-file (file-name)
(libc-search-index "File Index" file-name))
(defun libc-search-index (index item &optional prefix suffix)
"Search ITEM in the Info index INDEX and go to that Info node.
Value is ITEM or `nil' if an error occurs.
If PREFIX and/or SUFFIX are non-`nil', then search the Info node for
the first occurrence of the regular expression `PREFIX ITEM SUFFIX' and
leave point at the beginning of the first line of the match. ITEM will
be highlighted with `libc-highlight-face' iff `libc-highlight-face' is
not `nil'."
(condition-case nil
(save-selected-window
(or (get-buffer "*info*")
(save-window-excursion
(info)))
(switch-to-buffer-other-window "*info*")
(Info-goto-node (concat "(" libc-info-file-name ")" index))
(Info-menu item)
(if (or prefix suffix)
(let ((case-fold-search nil)
(buffer-read-only nil))
(goto-char (point-min))
(re-search-forward
(concat prefix (regexp-quote item) suffix))
(goto-char (match-beginning 0))
(and window-system libc-highlight-face
;; Search again for ITEM so that the first
;; occurence of ITEM will be highlighted.
(save-excursion
(re-search-forward (regexp-quote item))
(let ((start (match-beginning 0))
(end (match-end 0)))
(if (overlayp libc-highlight-overlay)
(move-overlay libc-highlight-overlay
start end (current-buffer))
(setq libc-highlight-overlay
(make-overlay start end))))
(overlay-put libc-highlight-overlay
'face libc-highlight-face)))
(beginning-of-line)))
item)
(error nil)))
(provide 'libc)
;;; libc.el ends here