From ffe4bb81f76fca12944dc6012eb32a351835d59a Mon Sep 17 00:00:00 2001
From: Sameer Rahmani <lxsameer@gnu.org>
Date: Mon, 19 Jun 2023 22:25:26 +0100
Subject: [PATCH] Add the noether-from-modeline macro to easily port modeline
 format strings to noether

---
 noether-units.el   |  9 +++++++--
 noether.el         | 39 +++++++++++++++++++++++++++++++++++++++
 noether.example.el |  3 ++-
 3 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/noether-units.el b/noether-units.el
index 8be5ff3..30b934f 100644
--- a/noether-units.el
+++ b/noether-units.el
@@ -69,8 +69,7 @@
     (format "%s%s %s"
             (if (buffer-modified-p buf) "*" "-")
             (if (verify-visited-file-modtime buf) "-" "*")
-            (string-trim v)))
-  )
+            (string-trim v))))
 
 
 (defunit buffer-name-unit
@@ -119,6 +118,12 @@ knowing."
   :var 'noether--time
   :fn #'noether--time-format)
 
+;; ============================================================================
+;; Mode name
+;; ============================================================================
+(noether-from-modeline mode-name-unit
+  "Returns the current mode name"
+  "" "%m" 16)
 
 
 (provide 'noether-units)
diff --git a/noether.el b/noether.el
index d96f3f4..4ad34f3 100644
--- a/noether.el
+++ b/noether.el
@@ -66,6 +66,44 @@ It will returen a pair in form of (body . props)."
    (make-string (noether--unit-get unit :len 0) ? )))
 
 
+(defmacro noether-from-modeline (name docs label format-str len)
+  "Define a new unit with the given NAME and doc-string DOCS from the modeline.
+It will use the given LABEL and LEN to pass the to the `defuit' macro.
+
+The most important part of this macro is the FORMAT-STR parameter.  It
+should be a format string that is understandable by `format-modeline'
+function."
+  (declare (doc-string 2) (indent defun))
+  (let ((new-var-sym (gensym)))
+    `(progn
+       (defvar ,(intern (format "%s--internal-state-var" (symbol-name name))))
+
+       (defun ,(intern (format "%s--update-internal-state-var" (symbol-name name))) ()
+         (setq ,(intern (format "%s--internal-state-var" (symbol-name name)))
+               (format-mode-line ,format-str)))
+
+
+       (defun ,(intern (format "%s--format-final-result" (symbol-name name))) (_ ,new-var-sym _ _)
+         "Format the buffer name V."
+         (string-trim ,new-var-sym))
+
+
+       (defunit ,name
+         ,docs
+         :label ,label
+         :len ,len
+         :init (lambda ()
+                 (add-hook 'post-command-hook
+                           #',(intern (format "%s--update-internal-state-var" (symbol-name name)))))
+
+         :deinit (lambda ()
+                   (remove-hook 'post-command-hook
+                                #',(intern (format "%s--update-internal-state-var" (symbol-name name)))))
+
+         :var ',(intern (format "%s--internal-state-var" (symbol-name name)))
+         :fn #',(intern (format "%s--format-final-result" (symbol-name name)))))))
+
+
 (defmacro defview (name docs &rest body)
   "Create a new view with the given NAME with the given DOCS and BODY.
 BODY will be parsed in a way that any starting pair of keyword and value
@@ -274,5 +312,6 @@ It reports them back in a status bar like frame."
     (mapc #'noether--teardown-views noether-views)))
 
 
+
 (provide 'noether)
 ;;; noether.el ends here
diff --git a/noether.example.el b/noether.example.el
index b4dfedc..f342c28 100644
--- a/noether.example.el
+++ b/noether.example.el
@@ -45,7 +45,8 @@
   (list
    (line-unit)
    (time-unit :label "Time:")
-   (buffer-name-unit)))
+   (buffer-name-unit)
+   (mode-name-unit)))
 
 
 (setq noether-views (list example-bar))