Xah Programing Blog Archive 2012-04
i got 2 smart programers who asked/questioned me about negative sign in decimal notation of latitude/longitude notation.
ok, here's explanation.
here's the coordinate for San Francisco:
latitude longitude 37°46′45.48″N 122°25′9.12″W
here's the decimal notation: 37.7793 -122.4192
lattitude is like y axis, going from -90° (south pole) to 90° (north pole). 0° is the equator.
In minute second notation, it usually uses “S” (South) for negative, and “N” (North) for positive, instead of positive/negative sign.
longitude, is like x-axis, but going from -180° to +180°. Negative is West (W), positive is East (E). 0° is artificially fixed at Greenwich, England. This line is called prime meridian. (Greenwich is in London) So, basically, any place east of london is positive, west of london is negative.
by convention, the order is latitude, longitude (contrary to math convention, where x is first, y second)
functional programing in perl is like using chopsticks at McDonalds: Best done at home.
- if you wrote a book on programing in the 1980s, you are a god.
- if you wrote a book on programing in the 1990s, you are respectable.
- if you wrote a book on programing in the 2000s, you might be that idiotic jock next door.
- 2023-07-11 if you wrote a book on programing in the 2010s, you are a grifter.
John Carmack Glorifying Functional Programing in 3k Words
John Carmack glorifying functional programing in 3k words
- Functional Programming in C++ By John-Carmack. At
http://www.altdevblogaday.com/2012/04/26/functional-programming-in-c/
where was he ten years ago?
[see Object Oriented Programing (OOP) Jargons and Complexities]
updated AutoHotkey Example Scripts
updated Windows Keyboard Software Guide
Google Chrome Browser Special URL
Firefox AutoScroll on Linux
To turn on autoscroll feature on Linux, paste about:config in the URL field, then set general.autoScroll to true.
[see Firefox: Set Mouse Wheel Scroll Speed]
svn upgrade error “svn: E155019”
Recently i upgrade all packages in Cygwin. When i did a commit, i got:
svn: E155019: Can't upgrade '/cygdrive/c/Users/h3/ErgoEmacs_Source/ergoemacs/ergoemacs' as it is not a pre-1.7 working copy root, the root is '/cygdrive/c/Users/h3/ErgoEmacs_Source/ergoemacs'
Oh no! Error! My mind is psychologically conditioned to think i'll need to spend a hour or more to fix whatever problem is this. Apparently, svn 1.7 changed its repository metadata format. Luckily, the solution is simple:
- cd to the root of your project's svn repository.
- do
svn upgrade - Repeat for other project's svn root.
Whew, that's not too bad.
[see svn Tutorial]
Why Tiling Window Manager Sucks
How to Use xmonad; xmonad Keybinding
created a new index, of articles on unix command line tutorial/essays. At Xah unix/linux tutorial .
Programing: Design Patterns Your Mom
Linux: How to Install New Window Manager
Set Bash Shell Prompt to Color
Job Interview Questions for Senior Linux Sys Admins
updated Computing: mega vs mibi, kilo vs kibi
updated Internet WIFI Speed Growth Rate
Why I Love PHP
i'll be going against the tide here. True, PHP is quite ugly, way inconsistent, and not as powerful.
But i'll have to say one thing. PHP is, in my opinion, the most useful, the most easy, the most comfortable and pleasurable language i've ever used. (in comparison to Perl, Python, Java, JavaScript DOM scripting.)
Also, i'd say PHP is the language that had the most impact on educating the masses about functional programing. Because, in PHP, everything is a function. Input, Output, that's it. No OOP shit. No currying, lambda jargon, tail recursion, complex mumbo jumbo. Exceedingly simple.
Also, PHP community is the one that lacks fanatics. For example, in Haskell, Scheme, when you ask a question, you get a bunch of garbage about monad, currying, combinator, call-with-continuation, tail recursion, “you doing it wrong!”, “why you want to do that?”, full proselytizations and often wrong info too. Same in Perl, Python. In PHP community, you never get that. Just straight answer.
Also, PHP doc is the best there is. No mumbo-jumbo jargons and shit that wants to make you believe.
Examples of Quality Documentation in Computing Industry
Keyboard Geeking: Backspace or Not Backspace? (Keys for Goto Previous Page in Windows and Linux)
in linux, the Backspace key is not used for goto previous page. For example, in Google Chrome or Firefox. The keys are Alt+← and Ctrl+[.
On Windows, you can use Backspace ⌫. And Shift+Backspace ⌫ for forward.
Xah Analysis: the Windows key is superior. (Sorry tech geekers of the unix faction.)
Reason:
The Backspace is not as logical. It's like, WTF? Backspace is for deleting backward. Especially so when you are posting a comment. The { Alt+←, Alt+→ } or { Ctrl+[, Ctrl+] } are more logical.
But the Backspace is more convenient, ergonomic, because it is a single key, and a big key.
The operation for “goto previous page” is one of the most needed key. Perhaps in top 5. (among {page up/down, goto file top/bottom, prev/next tab, close tab})
For such frequently needed key, convenient/ergonomic has far more priority than logicality.
Detail at: Keyboard Shortcut vs Launch Buttons .
See also:
aspell sucks: Dismal Vocabulary Size
Array Programing Language: APL, Mathematica
APL and Mathematica can both be categorized into a so-called Array programming language. It basically means, when a operand is a array/list, the operation is automatically mapped into the list. (as opposed to using a explicit “map” in lisp, perl, python.).
Here is APL implementation of normalizing a n-dimentional math vector.
normalize←{⍵÷((+/⍵⋆2)⋆0.5)}
Code by Tom Novelli. APL code can be run here: http://ngn.github.com/apl/web/index.html
.
Here is Mathematica:
normalize = Function[#/Sqrt@(Plus@@(#^2))]
For detail, see: Programing Problem: Normalize a Vector of Any Dimension
[see Create TeX / APL Keyboard Layout]
updated: Programing Problem: Normalize a Vector of Any Dimension
Emacs Lisp vs Perl: Validate Local File Links
updated The Bug-Reporting Attitude
Microsoft XP Bug Report Panels
Bjoern Paschen wrote a improved, idiomatic, version of python multi find/replace code we did before. See: Python Problem: String Methods, Functions, Slashes, Backslashes .
updated ImageMagick Tutorial
Math Font, Unicode, Gothic Letters, Double Struck, 𝔄 𝔅 ℭ
updated What Characters Are Not Allowed in File Names?
updated On Unix Filename Characters Problem
updated The Nature of the Unix Philosophy
updated Problems of Symbol Congestion in Computer Languages; ASCII Jam vs Unicode
Python Problem: String Methods, Functions, Slashes, Backslashes
updated: Ergonomic Keyboard Layouts
Ryan Dahl, on History of Node.js 📺
User Interface Design: Peepshow Windows
updated Why You should Not Use the Jargons lisp-1 lisp-2
The Meaning of Lisperati and Emacsen
Lisperati means lispers, lisp coders.
however, i just tried to google it for some definite confirmation. I think i read it in the 1990s from The Jargon File or LISP FAQ in newsgroup.
Strange, didn't find it after 5 min. Not in wikipedia lisp article. Was sure it's in jargon file or Online Free Computing Dictionary. Neither. comp.lang.lisp group search turned out 2 or so results other than lisperati.com (Conrad Barski, the LAND OF LISP book guy and alien lisp logo guy). Tried google group search 1990 to 2000, no result. (am pretty sure it's there, but google group search has been faaked since about 2005)
btw, emacsen is the hacker's jargon for the plural of emacs.
(thanks to Tim Bradshaw and Yuriv Khan for a correction.)
ELisp: read-from-minibuffer Propels Deep Questions
Intro to Wolfram Language Pattern Matching for Lisp Programers
updated Best Unicode Fonts for Programer