Xah Programing Blog Archive 2019-01

Unicode Geometric Shapes ■

updated on diamonds.

Why Python Lambda is Broken and Can't be Fixed

Lisp-1 vs Lisp-2

minor updates.

Webcams reverse left/right when self viewing

I just discovered. Webcams reverse left/right. Truly annoying when u r doing vids on objects, like keyboard. Apparently, they do that cuz people r used to see themselfs in mirrors. But this reversal stops when video is transmitted.

what an idiot i am. there are options to flip them in both QuickTime and PhotoBooth.

Microsoft Windows 10, Snip and Sketch app, file name save problem

utterly annoying. Now, in Microsoft Windows 10, Snip&Sketch app, the default name is


instead of

Annotations yyyy-mm-dd nnnnnn

, if you launch it from the Windows Ink Workspace.

This means, every time you save, you have to type a new name. This is a major pain when you are using Surface Pro as tablet, walking around and reading it (as i often use it that way), with no keyboard attached.

This started to happen today (2019-01-15), not sure it's a bug or what.

software lost preference settings

It used to be, software has preference/opts menu with elaborate settings. But since the phone era and win10, now it's just a few buttons. Nowhere to see settings for default name, often not even about and version number.

Donald Knuth, the prototype of inept and ineffectual nerd

video lectures by Donald Knuth. from i think 70s. https://www.youtube.com/playlist?list=PL94E35692EB9D36F3

never liked Knuth. In my 20s, 30s, like every coder, i admired Knuth. His books i've read, TeX series, meta font, literate programing, Art of Programing, Selected essays. Never liked any of them. He's the prototype of nerd. Turns out, he can't public speak well neither.

Knuth has also written about technical writing i read in 90s. i don't remember the title, but might be this one Buy at amazon it's, no good.

here's Knuth technical writing book online http://tex.loria.fr/typographie/mathwriting.pdf not sure it's a legal copy.

for great tech writing, it's not about correct grammar or clear sentence. Rather, it's about how deep you understand the subject. for writing great poetry, it's not about correct grammar or fancy sentence. it's about a vision, and how deep you know English.

text, pic, video, info density, and the quasi-science of info science

That's the thing. you trying to convince me using org+hugo, i no see any point. I try to show u the superiority of emacs+elisp+raw html, u no see the advantage. ∴ video chat + screen demo. that way, something gets across. They say, a pic is worth 1k words. A vid, is worth 1M words.

“They say,a pic is worth 1k words。A vid,is worth 1M words”. and actually, when you look their file sizes, it does indicate the info density. #Information #Science!

Library of Alexandria O Von Corven vVFqy
Library of Alexandria by O Von Corven

the so-called info science [ Information science ] [ 2019-01-15 https://en.wikipedia.org/wiki/Information_science ] often times, are actually quasi-science. it's often just programers and management selling their stuff.

What Languages to Hate

when i see the word #haskell, i can't despise it fast enough. it's no haskell i hate, but the pop currency, 'was java oop perl lisp python ruby rails. and u, current haskeller, r the skum of a bubble tea.

year 2002 What Languages to Hate

O, in the lore of coding, we've had fad of unix phil, oop, defensive programing, laziness of perl, slack input generously strict output xml mantra, eXtreme Programing, Patterns, sep of concerns, lisp homoiconicity, KISS, DRY, … fkthymom is proper.

See also: Software Engineering Voodoo

Golang: Script to Find Replace Multi-Pairs of Regex in a Directory


template systems Jeykell vs Hugo

Jeykell is written in #ruby, from 2008. Hugo is written in #golang, from year ? apparently recent. The obvious choice is hugo.

i write 5 thousand html pages raw manually, in #emacs xah-fly-keys and xah-html-mode. The number of keystrokes to create a html page, is less than markdown, org-mode, keykell, hugo, or whatnot template systems.

the price you pay, is that you have to know html, css, emacs lisp, well. What you get is far more power, efficiency, flexibility and control.

DuckDuckGo problem, JavaScript image search

one extremely annoying thing about @DuckDuckGo is that, if you have js off, u search something, then you want images, u turn on js, there's no way to navigate to it. u have to start a new tab, start js, goto duck, then img search. but in @brave, u can't start js untill a site is loaded

both google search and bing search don't have this problem.

shotcut video editor 2019-01-09 34249
shotcut video editor 2019-01-09


#linux can anyone give me basic instruction for cutting out 2 seconds of video? Am using @shotcutapp. First time editing video. Cutting out few frames (about 2 seconds) is all i need. Thanks

video needs to cut: 12:11.64 to 12.13.14. and aronud 11:37

Open the clip in the Source tab of the player. Use the selection controls to select the first part you want to keep. Add it to the Playlist (+ or drag-n-drop). Select the second part you want to keep. Add that to the Playlist. Click Export → Export File.

maybe here is a tutorial on how to cut frames https://make.wordpress.org/tv/handbook/video-editing/video-editor/#trimming-the-video

todo. it seems, other great free video editor includes Avidemux, OBS Studio.

Kdenlive is pretty good but for simple stuff ffmpeg/avconv can do. Works well for more low level stuff like cutting a small piece from a video

try this ffmpeg -i video.mp4 -ss 00:00:00 -t 00:00:10 -async 1 trimmed_video.mp4

How to Calibrate Monitor Color

the Journey of a Foreign Character thru Internet. old rant.

apple prevent repair

apple prevent repair 2019-01-06 75f7a
Apple tries to prevent you from repairing your iphone or macbook 2019-01-06

the Apple skum, creating things so that can't be repaired. on the other hand, note, how battery takes some 70% of the space. [ twitter iFixit ] [ 2019-01-15 https://twitter.com/iFixit/status/1084540649469345793 ]

Unicode Basics: Character Set, Encoding, UTF-8, Codepoint

How Popular is Unicode UTF-8 (updated)

Linux by Command Line

added new grouped nav boxes

update footer copyright year 2019-01-05 fa7d6
update footer copyright year

lol. though, technically, you only need to update a page when the page's content has been reworked or added. And, if not, it's actually legally questionable to claim a copyright of current year.

copyright xahlee 2019-01-04 5c2a8
copyright xahlee

xah programing language tutorial is great

mogakumono xahlee 2019-01-04 c0e4a

for the win

good video recording software: OBS

this seems to be a good video recording software, suggested to me by GrinDeg https://obsproject.com/

ok, here's my plan for 2019.

the progress/fruit of these undertaking will be reflected on my website. The #JavaScript coding d3js graphics lib will be at Visual Dictionary of Special Plane Curves namely, replace all images/animation by JavaScript

#math the study of differential geometry and complex analysis will be at http://virtualmathmuseum.org/index.html and also forming a book draft of the topic on my Math Blog Xah Math Blog or some new page.

the study of proof theory, is quite a lot areas. Various branches of logic, godel's stuff, computer algebra system, formal languages, coq, and possibly eventuall Homotopy Type Theory Homotopy Type Theory They'll be logged daily at my Programing Blog Xah Programing Blog

golang progress will be seen as i add to my golang tutorial. learn Golang in 1 day Golang Tutorial

the parser/compiler study will be seen as i improve/complete my parser/compiler tutorial at Formal Language, Grammar, Parser Formal Language, Grammar, Parser

Maintaining 5k Articles, and Snippets of Learning Notes

busied myself with my websites the whole day. Maintaining 5k articles is really perpetual work. also, been reading lots math since 2 months ago. good. though, haven't been really programing or reading about coding in past 2 months.

my sites are

so, let's say plans for 2019.

everytime i read math, typically for each 2 hours of reading, i often want to write a snippet of it of what i learned, in a easy to understand way and share here. though, it's actually difficult to do. Writing a few sentences may that takes 30 min or so.

example of such writing are, the 3 posts about pseudo random number last month [ twitter xah_lee ] [ 2019-01-02 https://twitter.com/xah_lee/status/1077418291860127744 ] to just write that few sentences, took some 4 hours of reading. and 9 out of 10 others times i wasn't able to write.

here's another example of math snippet last month [ twitter xah_lee ] [ 2019-01-02 https://twitter.com/xah_lee/status/1077667798506135552 ] i was reviewing my probability and statistics. To write math snippet on twitter, you have to have a overall picture of a subject first. then, craft to capture a snippet of theory or something interesting.

the math on Wikipedia is 1 big blackhole。it has improved&improved continuously since 2003。even back in 2010 it's good。but now more&better。not just math,but physics,engineering,etc all tech subjects,as well as history,literature,etc。Minus whatever current political hot button topic.