[Doc] Creating a common org files for personal Emacs notes

doc/emacs-notes.org

@@ -1,10 +1,11 @@
-#+TITLE: Notes on “Babel: Introduction”
-#+AUTHOR: Daniel
-#+DATE: 2016-06-26
+#+title: Notes on Emacs
+#+author: Daniel
+
+* Introduction to Babel
 
 Tutorial from http://orgmode.org/worg/org-contrib/babel/intro.html
 
-* Source Code Execution
+** Source Code Execution
 
 #+begin_src hy
   (print "Hello, There!")
@@ -30,7 +31,7 @@ Tutorial from http://orgmode.org/worg/org-contrib/babel/intro.html
 |-------------+-----------+------------+------+------+---------+----------+--------+--------+------|
 |           5 |         5 |          4 |    3 |    3 |       3 |        2 |      2 |      2 |    2 |
 
-** Capturing the Results of Code Evaluation
+*** Capturing the Results of Code Evaluation
 
 #+begin_src python :results value
   import time
@@ -53,11 +54,11 @@ Tutorial from http://orgmode.org/worg/org-contrib/babel/intro.html
 : Hello, today's date is Sun Jun 26 16:04:36 2016
 : Two plus two is
 
-** Session-based Evaluation
+*** Session-based Evaluation
 
 Have a look into /Emacs Speaks Statistics/
 
-** Arguments to Code Blocks
+*** Arguments to Code Blocks
 
 #+name: square
 #+header: :var x = 0
@@ -91,12 +92,12 @@ Have a look into /Emacs Speaks Statistics/
 | 1 | 1 | 2 |  3 |  5 |   8 |  13 |  21 |   34 |   55 |
 | 1 | 3 | 8 | 21 | 55 | 144 | 377 | 987 | 2584 | 6765 |
 
-** In-line Code Blocks
+*** In-line Code Blocks
 
 In-line code can be call without header arguments (like so: src_sh{date}) or
 with header arguments (like so: src_python[:results value]{return 10 + 10}).
 
-** Code Block Body Expansion
+*** Code Block Body Expansion
 
 Preview: =C-c C-v v=, bound to =org-babel-expand-src-block=
 
@@ -109,7 +110,7 @@ Preview: =C-c C-v v=, bound to =org-babel-expand-src-block=
 (setq my-special-password (first (second data)))
 #+end_src
 
-** A Meta-programming Language for Org-mode
+*** A Meta-programming Language for Org-mode
 
 #+name: directories
 #+begin_src sh :results replace
@@ -131,9 +132,9 @@ Preview: =C-c C-v v=, bound to =org-babel-expand-src-block=
 
 Note: the syntax =#+name: directory-pie-chart(dirs=directories)= did not work.
 
-** Using Code Blocks in Org Tables
+*** Using Code Blocks in Org Tables
 
-*** Example 1: Data Summaries Using R
+**** Example 1: Data Summaries Using R
 
 #+name: tbl-example-data
 #+begin_src R
@@ -151,17 +152,17 @@ Note: the syntax =#+name: directory-pie-chart(dirs=directories)= did not work.
 | 0.574235895462334 |
 #+TBLFM: @2$1='(org-sbe "R-mean" (x "tbl-example-data()"))
 
-*** Example 2: Babel Test Suite
+**** Example 2: Babel Test Suite
 
 /No notes/
 
-* The Library of Babel
+** The Library of Babel
 
 #+lob: square(x=6)
 
 Does not do what I expected …
 
-* Literate Programming
+** Literate Programming
 
 #+name: hello-world-prefix
 #+begin_src sh :exports none
@@ -182,4 +183,74 @@ Does not do what I expected …
 
 Tangling with =C-c C-v t=.
 
-* Reproducible Research
+** Reproducible Research
+
+* Random Notes
+** How to paste then copy                                              :NOTE:
+:PROPERTIES:
+:CREATED: [2018-08-11 Sat 21:47]
+:END:
+:LOGBOOK:
+CLOCK: [2018-08-11 Sat 21:47]--[2018-08-11 Sat 21:48] =>  0:01
+:END:
+
+Question: how to set a mark such that all subsequent copy operations move their
+text to that exact mark.
+
+Answer: use ~cua-selection-mode~!  See
+https://www.reddit.com/r/emacs/comments/8ekz0u/how_to_pastethencopy/.
+
+/Update/: turns out it doesn’t work so well, disabled it again.
+** Tramp and Telnet over non-standard ports                            :NOTE:
+:PROPERTIES:
+:CREATED: [2018-12-29 Sat 15:58]
+:END:
+
+Syntax: ~/telnet:HOST#PORT:~, works also with other protocols.
+
+** Magit Walkthrough                                                   :NOTE:
+:PROPERTIES:
+:CREATED: [2018-08-11 Sat 21:05]
+:END:
+
+https://emacsair.me/2017/09/01/magit-walk-through/
+** Fractals in Emacs                                                   :NOTE:
+:PROPERTIES:
+:CREATED: [2018-08-04 Sat 13:01]
+:END:
+:LOGBOOK:
+CLOCK: [2018-08-04 Sat 13:01]--[2018-08-04 Sat 13:03] =>  0:02
+:END:
+
+From https://nullprogram.com/blog/2012/09/14/
+
+#+begin_src emacs-lisp
+(defun sierpinski (s)
+  (pop-to-buffer (get-buffer-create "*sierpinski*"))
+  (fundamental-mode) (erase-buffer)
+  (labels ((fill-p (x y)
+                   (cond ((or (zerop x) (zerop y)) "0")
+                         ((and (= 1 (mod x 3)) (= 1 (mod y 3))) "1")
+                         (t (fill-p (/ x 3) (/ y 3))))))
+    (insert (format "P1\n%d %d\n" s s))
+    (dotimes (y s) (dotimes (x s) (insert (fill-p x y) " "))))
+  (image-mode))
+
+(defun mandelbrot ()
+  (pop-to-buffer (get-buffer-create "*mandelbrot*"))
+  (let ((w 400) (h 300) (d 32))
+    (fundamental-mode) (erase-buffer)
+    (set-buffer-multibyte nil)
+    (insert (format "P6\n%d %d\n255\n" w h))
+    (dotimes (y h)
+      (dotimes (x w)
+        (let* ((cx (* 1.5 (/ (- x (/ w 1.45)) w 0.45)))
+               (cy (* 1.5 (/ (- y (/ h 2.0)) h 0.5)))
+               (zr 0) (zi 0)
+               (v (dotimes (i d d)
+                    (if (> (+ (* zr zr) (* zi zi)) 4) (return i)
+                      (psetq zr (+ (* zr zr) (- (* zi zi)) cx)
+                             zi (+ (* (* zr zi) 2) cy))))))
+          (insert-char (floor (* 256 (/ v 1.0 d))) 3))))
+    (image-mode)))
+#+end_src