(Emacs/config|elisp)~rework Eshell

Now I have separate modules for the additional new functions I
introduced for eshell and for the prompt function I made.  Cleans up
the configuration a bit and makes it easier to examine those files on
their own, which I expect to grow.

4 files changed, 216 insertions, 124 deletions

diff --git a/Emacs/.config/emacs/.config/eshell/aliases b/Emacs/.config/emacs/.config/eshell/aliases
index 8686c44..c7effa4 100644
--- a/Emacs/.config/emacs/.config/eshell/aliases
+++ b/Emacs/.config/emacs/.config/eshell/aliases
@@ -5,4 +5,4 @@ alias gs magit-status
 alias clear clear-scrollback
 alias d dired-other-window $1
 alias gt goto
-alias p~ project-root
+alias pr project-root
diff --git a/Emacs/.config/emacs/config.org b/Emacs/.config/emacs/config.org
index 84c25e1..3411eea 100644
--- a/Emacs/.config/emacs/config.org
+++ b/Emacs/.config/emacs/config.org
@@ -1686,16 +1686,27 @@ expression it tries to evaluate it by testing against these conditions:
 - it's an external command (bash evaluator)
 Essentially, you get the best of both Emacs and external shell
 programs *ALL WITHIN* Emacs for free.
-*** Eshell functionality
-Bind some evil-like movements for easy shell usage, and a toggle
-function to pull up the eshell quickly.
+*** Eshell keymaps, display and variables
+Bind some evil-like movements for easy shell usage, a display record
+so when you call eshell it kinda looks like VSCode's terminal popup.
+
+NOTE: This mode doesn't allow you to set maps the normal way; you need
+to set keybindings on eshell-mode-hook, otherwise it'll just overwrite
+them.
 #+begin_src emacs-lisp
 (use-package eshell
   :defer t
   :general
   (shell-leader
     "t" #'eshell)
+  :display
+  ("\\*e?shell\\*"
+   (display-buffer-at-bottom)
+   (window-height . 0.33))
   :init
+  (setq eshell-cmpl-ignore-case t
+        eshell-cd-on-directory t
+        eshell-highlight-prompt nil)
   (add-hook
    'eshell-mode-hook
    (proc
@@ -1703,6 +1714,7 @@ function to pull up the eshell quickly.
     (general-def
       :states '(normal insert)
       :keymaps 'eshell-mode-map
+      "0"   #'eshell-bol
       "M-j" #'eshell-next-matching-input-from-input
       "M-k" #'eshell-previous-matching-input-from-input)
     (local-leader
@@ -1711,134 +1723,45 @@ function to pull up the eshell quickly.
                 (recenter))
       "k" #'eshell-kill-process))))
 #+end_src
-*** Eshell pretty symbols and display
-Pretty symbols and a display record.
-#+begin_src emacs-lisp
-(use-package eshell
-  :defer t
-  :display
-  ("\\*e?shell\\*" ; for general shells as well
-   (display-buffer-at-bottom)
-   (window-height . 0.33)))
-#+end_src
-*** Eshell variables and aliases
-Set some sane defaults, a banner and a prompt.  The prompt checks for
-a git repo in the current directory and provides some extra
-information in that case (in particular, branch name and if there any
-changes that haven't been committed).
+*** Eshell prompt
+Here I use my external library
+[[file:elisp/eshell-prompt.el][eshell-prompt]], which provides a more
+dynamic prompt for Eshell.  Current features include:
++ Git (with difference from remote and number of modified files)
++ Current date and time
++ A coloured prompt which changes colour based on the exit status of
+  the previous command
 
+NOTE: I don't defer this package because it doesn't use any eshell
+internals, just standard old Emacs packages.
 #+begin_src emacs-lisp
-(use-package eshell
-  :defer t
+(use-package eshell-prompt
+  :load-path "elisp/"
   :config
-  (defun +eshell/--git-get-remote-status ()
-    (let* ((branch-status (split-string
-                           (shell-command-to-string "git status | grep 'Your branch is'")))
-           (status (nth 3 branch-status))
-           (diff (cl-position "by" branch-status :test #'string=)))
-      (if (null diff)
-          (propertize "=" 'font-lock-face '(:foreground "green"))
-        (let ((n (nth (+ 1 diff) branch-status)))
-          (concat
-           (cond
-            ((string= status "ahead")
-             (propertize "→ " 'font-lock-face '(:foreground "dodger blue")))
-            ((string= status "behind")
-             (propertize "← " 'font-lock-face '(:foreground "orange red"))))
-           n)))))
-
-  (defun +eshell/--git-get-change-status ()
-    (let ((changed-files (- (length (split-string (shell-command-to-string "git status -s" ) "\n")) 1)))
-      (if (= changed-files 0)
-          (propertize "✓" 'font-lock-face '(:foreground "green"))
-        (propertize (number-to-string changed-files) 'font-lock-face '(:foreground "red")))))
-
-  (defun +eshell/get-git-properties ()
-    (let ((git-branch (shell-command-to-string "git branch")))
-      (if (or (string= git-branch "")
-             (not (string= "*" (substring git-branch 0 1))))
-          ""
-        (format
-         "(%s<%s>[%s])"
-         (nth 2 (split-string git-branch "\n\\|\\*\\| "))
-         (+eshell/--git-get-change-status)
-         (+eshell/--git-get-remote-status)))))
-
-  (defun +eshell/prompt-function ()
-    (let ((git (+eshell/get-git-properties)))
-      (mapconcat
-       (lambda (item)
-         (if (listp item)
-             (propertize (car item)
-                         'read-only t
-                         'font-lock-face (cdr item)
-                         'front-sticky   '(font-lock-face read-only)
-                         'rear-nonsticky '(font-lock-face read-only))
-           item))
-       (list
-        '("[")
-        `(,(abbreviate-file-name (eshell/pwd)) :foreground "LimeGreen")
-        '("]")
-        (if (string= git "")
-            ""
-          (concat "-" git ""))
-        "\n"
-        `(,(format-time-string "[%H:%M:%S]") :foreground "purple")
-        "\n"
-        '("𝜆> " :foreground "DeepSkyBlue")))))
-
   (defun +eshell/banner-message ()
     (concat (shell-command-to-string "~/.local/scripts/cowfortune")
             "\n"))
-
-  (setq eshell-cmpl-ignore-case t
-        eshell-cd-on-directory t
-        eshell-banner-message '(+eshell/banner-message)
-        eshell-highlight-prompt nil
-        eshell-prompt-function #'+eshell/prompt-function
-        eshell-prompt-regexp "^𝜆> "))
-#+end_src
-*** Eshell change directory quickly
-Add ~eshell/goto~, which is actually a command accessible from within
-eshell (this is because ~eshell/*~ creates an accessible function
-within eshell with name ~*~).  ~eshell/goto~ makes it easier to change
-directories by using Emacs' find-file interface (which is much faster
-than ~cd ..; ls -l~).
-
-~eshell/goto~ is a better ~cd~ for eshell.  However it is really just
-a plaster over a bigger issue for my workflow; many times I want
-eshell to be present in the current directory of the buffer I am
-using.  So here's also a command for opening eshell with the current
-directory.
-#+begin_src emacs-lisp
-(use-package eshell
-  :defer t
+  (setq eshell-prompt-regexp (format "^%s" +eshell-prompt/user-prompt)
+        eshell-prompt-function #'+eshell-prompt/make-prompt
+        eshell-banner-message '(+eshell/banner-message)))
+#+end_src
+*** Eshell additions
+Using my external library
+[[file:elisp/eshell-additions.el][eshell-additions]], I get a few new
+eshell internal commands and a surface command to open eshell at the
+current working directory.
+
+NOTE: I don't defer this package because it autoloads any eshell
+internals that it uses so I'm only loading what I need to.  Any
+~eshell/*~ functions need to be known by eshell before launching, so
+if I loaded this ~:after~ eshell then the first instance has no
+knowledge of the new additions.
+#+begin_src emacs-lisp
+(use-package eshell-additions
+  :load-path "elisp/"
   :general
   (leader
-    "T" #'+eshell/current-buffer)
-  :config
-  (defun eshell/goto (&rest args)
-    "Use `read-directory-name' to change directories."
-    (eshell/cd (list (read-directory-name "Directory?: "))))
-
-  (defun eshell/project-root (&rest args)
-    "Change to directory `project-root'"
-    (if (project-current)
-        (eshell/cd (list (project-root (project-current))))
-      (eshell/echo (format "[%s]: No project in current directory"
-                           (propertize "Error" 'font-lock-face '(:foreground "red"))))))
-
-  (defun +eshell/current-buffer ()
-    (interactive)
-    (let  ((dir (if buffer-file-name
-                    (file-name-directory buffer-file-name)
-                  default-directory))
-           (buf (eshell)))
-      (if dir
-          (with-current-buffer buf
-            (eshell/cd dir)
-            (eshell-send-input))
-        (message "Could not switch eshell: buffer is not real file")))))
+    "T" #'+eshell/at-cwd))
 #+end_src
 ** WAIT Elfeed
 :PROPERTIES:
diff --git a/Emacs/.config/emacs/elisp/eshell-additions.el b/Emacs/.config/emacs/elisp/eshell-additions.el
new file mode 100644
index 0000000..94c948f
--- /dev/null
+++ b/Emacs/.config/emacs/elisp/eshell-additions.el
@@ -0,0 +1,57 @@
+;;; eshell-additions.el --- Some aliases for Eshell    -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024  Aryadev Chavali
+
+;; Author: Aryadev Chavali <aryadev@aryadevchavali.com>
+;; Keywords:
+
+;; 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 version 2 of the License
+
+;; This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;
+
+;;; Code:
+
+(autoload #'eshell/cd "eshell")
+(autoload #'eshell/echo "eshell")
+(autoload #'eshell/send-input "eshell")
+
+;; Aliases
+(defun eshell/goto (&rest args)
+  "Use `read-directory-name' to change directories"
+  (eshell/cd (list (read-directory-name "Directory?: "))))
+
+(defun eshell/project-root (&rest args)
+  "Change to directory `project-root'"
+  (if (project-current)
+      (eshell/cd (list (project-root (project-current))))
+    (let ((error-msg (propertize "Error" 'font-lock-face
+                                 '(:foreground "red"))))
+      (eshell/echo
+       (format "[%s]: No project in current directory" error-msg)))))
+
+;; Additional functions
+(defun +eshell/at-cwd ()
+  "Open an instance of eshell at the current working directory."
+  (interactive)
+  (let ((dir (if buffer-file-name
+                 (file-name-directory buffer-file-name)
+               default-directory))
+        (buf (eshell)))
+    (with-current-buffer buf
+      (eshell/cd dir)
+      (eshell-send-input))))
+
+(provide 'eshell-additions)
+;;; eshell-additions.el ends here
diff --git a/Emacs/.config/emacs/elisp/eshell-prompt.el b/Emacs/.config/emacs/elisp/eshell-prompt.el
new file mode 100644
index 0000000..7e78c7c
--- /dev/null
+++ b/Emacs/.config/emacs/elisp/eshell-prompt.el
@@ -0,0 +1,112 @@
+;;; eshell-prompt.el --- Generating a good prompt for Eshell  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024  Aryadev Chavali
+
+;; Author: Aryadev Chavali <aryadev@aryadevchavali.com>
+;; Keywords:
+
+;; 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 version 2 of the License.
+
+;; This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; We provide a function +eshell-prompt which generates a prompt on
+;; demand.
+
+;;; Code:
+
+(defvar +eshell-prompt/user-prompt "𝜆> "
+  "Prompt for user to input.")
+
+(defun +eshell-prompt/--colour-on-last-command ()
+  "Returns an Emacs colour based on ESHELL-LAST-COMMAND-STATUS."
+  (if (zerop eshell-last-command-status)
+      "forestgreen"
+    "darkred"))
+
+(defun +eshell-prompt/--git-remote-status ()
+  "Returns a propertized string for the status of a repository
+in comparison to its remote.  3 differing strings are returned
+dependent on:
+
+- Is it equivalent to the remote?
+- Is it ahead of the remote?
+- Is it behind the remote?
+
+The latter 2 also have a number for exactly how many commits
+behind or ahead the local repository is."
+  (let* ((git-cmd "git status | grep 'Your branch is'")
+         (branch-status (split-string (shell-command-to-string git-cmd)))
+         (status (nth 3 branch-status))
+         (diff (cl-position "by" branch-status :test #'string=)))
+    (if (null diff)
+        (propertize "=" 'font-lock-face '(:foreground "green"))
+      (let ((n (nth (+ 1 diff) branch-status)))
+        (concat
+         (cond
+          ((string= status "ahead")
+           (propertize "→ " 'font-lock-face '(:foreground "dodger blue")))
+          ((string= status "behind")
+           (propertize "← " 'font-lock-face '(:foreground "orange red"))))
+         n)))))
+
+(defun +eshell-prompt/--git-change-status ()
+  "Returns a propertized string for the condition of the worktree in
+a repository.  If there are no changes i.e. the worktree is clean
+then a green tick is returned, but if there are changes then the
+number of files affected are returned in red."
+  (let* ((git-cmd "git status -s")
+         (command-output (split-string git-cmd))
+         (changed-files (- (length command-output) 1)))
+    (if (= changed-files 0)
+        (propertize "✓" 'font-lock-face '(:foreground "green"))
+      (propertize (number-to-string changed-files) 'font-lock-face '(:foreground "red")))))
+
+(defun +eshell-prompt/--git-status ()
+  "Returns a completely formatted string of
+form (BRANCH-NAME<CHANGES>[REMOTE-STATUS])."
+  (let ((git-branch (shell-command-to-string "git brnach")))
+    (if (or (string= git-branch "")
+           (not (string= "*" (substring git-branch 0 1))))
+        ""
+      (format
+       "(%s<%s>[%s])"
+       (nth 2 (split-string git-branch "\n\\|\\*\\| "))
+       (+eshell-prompt/--git-change-status)
+       (+eshell-prompt/--git-remote-status)))))
+
+(defun +eshell-prompt/make-prompt ()
+  (let ((git (+eshell-prompt/--git-status)))
+    (mapconcat
+     (lambda (item)
+       (if (listp item)
+           (propertize (car item)
+                       'read-only t
+                       'font-lock-face (cdr item)
+                       'front-sticky   '(font-lock-face read-only)
+                       'rear-nonsticky '(font-lock-face read-only))
+         item))
+     (list
+      "["
+      `(,(abbreviate-file-name (eshell/pwd)) :foreground "LimeGreen")
+      "]"
+      (if (string= git "")
+          ""
+        (concat "-" git ""))
+      "\n"
+      `(,(format-time-string "[%H:%M:%S]") :foreground "purple")
+      "\n"
+      (list "𝜆> " ':foreground (+eshell-prompt/--colour-on-last-command))))))
+
+
+(provide 'eshell-prompt)
+;;; eshell-prompt.el ends here