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;;; helm-info.el --- Browse info index with helm -*- lexical-binding: t -*-
;; Copyright (C) 2012 ~ 2016 Thierry Volpiatto <>
;; This program 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 3 of the License, or
;; (at your option) any later version.
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with this program. If not, see <>.
;;; Code:
(require 'cl-lib)
(require 'helm)
(require 'helm-lib)
(require 'info)
(declare-function Info-index-nodes "info" (&optional file))
(declare-function Info-goto-node "info" (&optional fork))
(declare-function Info-find-node "info.el" (filename nodename &optional no-going-back))
(defvar Info-history)
(defvar Info-directory-list)
;;; Customize
(defgroup helm-info nil
"Info-related applications and libraries for Helm."
:group 'helm)
(defcustom helm-info-default-sources
"Default sources to use for looking up symbols at point in Info
files with `helm-info-at-point'."
:group 'helm-info
:type '(repeat (choice symbol)))
;;; Build info-index sources with `helm-info-source' class.
(cl-defun helm-info-init (&optional (file (helm-attr 'info-file)))
;; Allow reinit candidate buffer when using edebug.
(helm-aif (and debug-on-error
(kill-buffer it))
(unless (helm-candidate-buffer)
(info file)
(let ((tobuf (helm-candidate-buffer 'global))
start end line)
(cl-dolist (node (Info-index-nodes))
(Info-goto-node node)
(goto-char (point-min))
(while (search-forward "\n* " nil t)
(unless (search-forward "Menu:\n" (1+ (point-at-eol)) t)
(setq start (point-at-bol)
;; Fix issue #1503 by getting the invisible
;; info displayed on next line in long strings.
;; e.g "* Foo.\n (line 12)" instead of
;; "* Foo.(line 12)"
end (or (save-excursion
(goto-char (point-at-bol))
(re-search-forward "(line +[0-9]+)" nil t))
;; Long string have a new line inserted before the
;; invisible spec, remove it.
line (replace-regexp-in-string
"\n" "" (buffer-substring start end)))
(with-current-buffer tobuf
(insert line)
(insert "\n")))))))))
(defun helm-info-goto (node-line)
(Info-goto-node (car node-line))
(helm-goto-line (cdr node-line)))
(defun helm-info-display-to-real (line)
(and (string-match
;; This regexp is stolen from Info-apropos-matches
"\\* +\\([^\n]*.+[^\n]*\\):[ \t]+\\([^\n]*\\)\\.\\(?:[ \t\n]*(line +\\([0-9]+\\))\\)?" line)
(cons (format "(%s)%s" (helm-attr 'info-file) (match-string 2 line))
(string-to-number (or (match-string 3 line) "1")))))
(defclass helm-info-source (helm-source-in-buffer)
((info-file :initarg :info-file
:initform nil
:custom 'string)
(init :initform #'helm-info-init)
(display-to-real :initform #'helm-info-display-to-real)
(get-line :initform #'buffer-substring)
(action :initform '(("Goto node" . helm-info-goto)))))
(defmacro helm-build-info-source (fname &rest args)
`(helm-make-source (concat "Info Index: " ,fname) 'helm-info-source
:info-file ,fname ,@args))
(defun helm-build-info-index-command (name doc source buffer)
"Define a helm command NAME with documentation DOC.
Arg SOURCE will be an existing helm source named
`helm-source-info-<NAME>' and BUFFER a string buffer name."
(defalias (intern (concat "helm-info-" name))
(lambda ()
(helm :sources source
:buffer buffer
:candidate-number-limit 1000))
(defun helm-define-info-index-sources (var-value &optional commands)
"Define helm sources named helm-source-info-<NAME>.
Sources are generated for all entries of `helm-default-info-index-list'.
If COMMANDS arg is non-nil, also build commands named `helm-info-<NAME>'.
Where NAME is an element of `helm-default-info-index-list'."
(cl-loop for str in var-value
for sym = (intern (concat "helm-source-info-" str))
do (set sym (helm-build-info-source str))
when commands
do (helm-build-info-index-command
str (format "Predefined helm for %s info." str)
sym (format "*helm info %s*" str))))
(defun helm-info-index-set (var value)
(set var value)
(helm-define-info-index-sources value t))
;;; Search Info files
;; `helm-info' is the main entry point here. It prompts the user for an Info
;; file, then a term in the file's index to jump to.
(defvar helm-info-searched (make-ring 32)
"Ring of previously searched Info files.")
(defun helm-get-info-files ()
"Return list of Info files to use for `helm-info'.
Elements of the list are strings of Info file names without
extensions (e.g. \"emacs\" for file \"\"). Info
files are found by searching directories in
(let ((files (cl-loop for d in (or Info-directory-list
when (file-directory-p d)
append (directory-files d nil "\\.info"))))
(cl-loop for f in files collect
(helm-file-name-sans-extension f))
:test 'equal)))
(defcustom helm-default-info-index-list
"Info files to search in with `helm-info'."
:group 'helm-info
:type '(repeat (choice string))
:set 'helm-info-index-set)
(defun helm-info-search-index (candidate)
"Search the index of CANDIDATE's Info file using the function
(let ((helm-info-function
(intern-soft (concat "helm-info-" candidate))))
(when (fboundp helm-info-function)
(funcall helm-info-function)
(ring-insert helm-info-searched candidate))))
(defun helm-def-source--info-files ()
"Return a `helm' source for Info files."
(helm-build-sync-source "Helm Info"
(lambda () (copy-sequence helm-default-info-index-list))
:candidate-number-limit 999
(lambda (candidates)
(sort candidates #'string-lessp))
:nomark t
:action '(("Search index" . helm-info-search-index))))
(defun helm-info ()
"Preconfigured `helm' for searching Info files' indices."
(let ((default (unless (ring-empty-p helm-info-searched)
(ring-ref helm-info-searched 0))))
(helm :sources (helm-def-source--info-files)
:buffer "*helm Info*"
:preselect (and default
(concat "\\_<" (regexp-quote default) "\\_>")))))
;;;; Info at point
;; `helm-info-at-point' is the main entry point here. It searches for the
;; symbol at point through the Info sources defined in
;; `helm-info-default-sources' and jumps to it.
(defvar helm-info--pages-cache nil
"Cache for all Info pages on the system.")
(defvar helm-source-info-pages
(helm-build-sync-source "Info Pages"
:init #'helm-info-pages-init
:candidates (lambda () helm-info--pages-cache)
:action '(("Show with Info" .(lambda (node-str)
(info (replace-regexp-in-string
"^[^:]+: " "" node-str)))))
:requires-pattern 2)
"Helm source for Info pages.")
(defun helm-info-pages-init ()
"Collect candidates for initial Info node Top."
(if helm-info--pages-cache
(let ((info-topic-regexp "\\* +\\([^:]+: ([^)]+)[^.]*\\)\\.")
(Info-find-node "dir" "top")
(goto-char (point-min))
(while (re-search-forward info-topic-regexp nil t)
(push (match-string-no-properties 1) topics))
(setq helm-info--pages-cache topics))))
(defun helm-info-at-point ()
"Preconfigured `helm' for searching info at point.
With a prefix-arg insert symbol at point."
(helm :sources helm-info-default-sources
:buffer "*helm info*"))
(provide 'helm-info)
;; Local Variables:
;; byte-compile-warnings: (not obsolete)
;; coding: utf-8
;; indent-tabs-mode: nil
;; End:
;;; helm-info.el ends here