From 093ffa5fbf7143f4668bb0a3dc9659a5cc836e12 Mon Sep 17 00:00:00 2001
From: Yuchen Pei <id@ypei.org>
Date: Sat, 17 Jun 2023 17:20:29 +1000
Subject: Moving things one level deeper

To ease gnu stow usage. Now we can do

stow -t ~ emacs
---
 emacs/.emacs.d/lisp/my/my-help.el | 138 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 emacs/.emacs.d/lisp/my/my-help.el

(limited to 'emacs/.emacs.d/lisp/my/my-help.el')

diff --git a/emacs/.emacs.d/lisp/my/my-help.el b/emacs/.emacs.d/lisp/my/my-help.el
new file mode 100644
index 0000000..27c23ce
--- /dev/null
+++ b/emacs/.emacs.d/lisp/my/my-help.el
@@ -0,0 +1,138 @@
+;;; my-help.el -- Help related extensions for emacs core -*- lexical-binding: t -*-
+
+;; Copyright (C) 2023 Free Software Foundation.
+
+;; Author: Yuchen Pei <id@ypei.org>
+;; Package-Requires: ((emacs "28.2"))
+
+;; This file is part of dotfiles.
+
+;; dotfiles is free software: you can redistribute it and/or modify it under
+;; the terms of the GNU Affero General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; dotfiles 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 Affero General
+;; Public License for more details.
+
+;; You should have received a copy of the GNU Affero General Public
+;; License along with dotfiles.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Emacs help related extensions.
+
+;;; Code:
+
+
+;; find source of external command
+(defun my-external-command-open-source (command)
+  (interactive
+   (list (completing-read
+          "Open source of command: "
+          (my-external-command-collection))))
+  (let ((subject
+         (cadr
+          (split-string (my-shell-command-output
+                         (format "type %s" command))
+                        " is "))))
+    (pcase subject
+      ("a shell builtin" (error "%s is %s" command subject))
+      ("a shell keyword" (error "%s is %s" command subject))
+      ((guard (string-prefix-p "is aliased to " subject))
+       (substring subject (error "%s is %s" command subject)))
+      (_
+       (pcase-let
+           ((`(,path ,type)
+             (split-string 
+              (my-shell-command-output (format "file -Li %s" subject))
+              ": ")))
+         (if (string-prefix-p "text/" type)
+             (progn
+               (message "Opening %s" path)
+               (find-file path))
+           (error "%s (%s) is not plaintext: %s" command path type)))))))
+
+(defun my-external-command-collection ()
+  (mapcan
+   (lambda (dir)
+     (mapcar
+      (lambda (file)
+        (string-match "\\(?:.*\\)/\\(.*\\)" file)
+        (match-string 1 file))
+      (seq-filter
+       (lambda (file)
+         (and (not (file-directory-p file))
+              (file-executable-p file)))
+       (directory-files dir t "[^~#]$"))))
+   (seq-filter
+    'file-accessible-directory-p
+    (exec-path))))
+
+(defun my-woman-man (arg)
+  (interactive "P")
+  (if arg (call-interactively 'man)
+    (call-interactively 'woman)))
+
+(defun my-help-goto-symbol (symbol)
+  (interactive
+   ;; copied from prompt code of help-describe-symbol
+   (let* ((v-or-f (symbol-at-point))
+          (found (if v-or-f (cl-some (lambda (x) (funcall (nth 1 x) v-or-f))
+                                     describe-symbol-backends)))
+          (v-or-f (if found v-or-f (function-called-at-point)))
+          (found (or found v-or-f))
+          (enable-recursive-minibuffers t)
+          (val (completing-read (format-prompt "Describe symbol"
+                                               (and found v-or-f))
+				                        #'help--symbol-completion-table
+				                        (lambda (vv)
+                                  (cl-some (lambda (x) (funcall (nth 1 x) vv))
+                                           describe-symbol-backends))
+				                        t nil nil
+				                        (if found (symbol-name v-or-f)))))
+     (list (if (equal val "")
+	             (or v-or-f "") (intern val)))))
+  (help-do-xref nil #'describe-symbol (list symbol)))
+
+(defun my-describe-local-variable (variable &optional buffer frame)
+  (interactive
+   (let ((v (variable-at-point))
+	       (enable-recursive-minibuffers t)
+         (orig-buffer (current-buffer))
+	       val)
+     (setq val (completing-read
+                (format-prompt "Describe variable" (and (symbolp v) v))
+                #'help--symbol-completion-table
+                (lambda (vv)
+                  (and (local-variable-p vv)
+                       (or (get vv 'variable-documentation)
+                           (and (not (keywordp vv))
+                                ;; Since the variable may only exist in the
+                                ;; original buffer, we have to look for it
+                                ;; there.
+                                (buffer-local-boundp vv orig-buffer)))))
+                t nil nil
+                (if (symbolp v) (symbol-name v))))
+     (list (if (equal val "")
+	             v (intern val)))))
+  (describe-variable variable buffer frame))
+
+(defun my-info-display-manual ()
+  (interactive)
+  (call-interactively 'info-display-manual)
+  (when (derived-mode-p 'Info-mode)
+    (rename-buffer
+     (generate-new-buffer-name
+      (format "*info %s*"
+              (file-name-sans-extension
+		           (file-name-nondirectory Info-current-file)))))))
+
+(defun my-describe-symbol-at-point ()
+  (interactive)
+  (describe-symbol (symbol-at-point)))
+
+(provide 'my-help)
+;;; my-help.el ends here
-- 
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