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Showing posts from April 25, 2010

Knitting, Chinese Knots, Braid Theory

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Perm url with updates: http://xahlee.org/math/math_knitting_chinese_knots.htmlKnitting, Chinese Knots, Braid TheoryXah Lee, 2010-04-30Am fascinated by the math aspects of knitting... e.g. the pure math aspect of how those threads are inter-woven, such as in Braid theory.Knitting. Source Cable kniting. Source Besides the math aspect of which thread are intertwined with which other threads in what way, it is also possible to create a pattern on the surface. What such patterns are possible, how are they made, must by itself be a complex theory.Lace tablecloth made using knitting needles. Source Chinese KnotsAlso related is Chinese knotting.Chinese knot. Source This one has the characteristics of fractal. Chinese knots. Source Chinese knot. Source Chinese knots. Source Discovered this fantastic book, free: 《ENCYCLOPEDIA OF NEEDLEWORK》 (1884), By Thérèse De Dillmont. At Source.It provides in-depth coverage, with hundreds of clear illustrations, many of which shows the pure weaving beauty of mat…

Keyboard Shortcut Design

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Perm url with updates: http://xahlee.org/comp/keyboard_shortcut_design.htmlKeyboard Shortcut Design: Dedicated keys, Special Buttons, Extra KeysXah Lee, 2010-04-30, 2010-06-13, 2011-03-06, 2011-05-27Spent few hours obsessing with key shortcut design again. Re-organizing my 100+ shortcut keys among applications, re-wrote and organized my AutoHotkey scripts, created a page of AutoHotkey example scripts: AutoHotkey Example Scripts, much time spend on thinking about the shortcut design.For example, in a keyboard shortcut system, there are issues of global keyset, and keyset local to applications, and there are standard typing oriented keys (e.g. a b c, 1 2 3, ! @ # etc.), special function keys (e.g. F1 F2, PageUp, PageDown, etc), specialized buttons (such as those buttons and knobs of multimedia keyboards). Then, there's also several key software systems, those from OS (e.g. 【Win+e】, 【Win+l】, …), and keyboard driver (e.g. IntelliType ), and specialized macro/launch software (AutoHot…

comp.lang.lisp is 95% Spam

Perm url with updates: http://xahlee.org/UnixResource_dir/writ2/google_group_lisp_spam.htmlcomp.lang.lisp is 95% SpamXah Lee, 2010-04-23today, comp.lang.lisp is 95% spam.let's help save it. Regardless what newsgroup readers you use, when you do your daily newsgroup reading, please take 15 seconds to go to: http://groups.google.com/group/comp.lang.lisp/topicsthen, click on the “Report as spam” for the 10 spam posts that shows on the first page.Thanks. Xah ∑ http://xahlee.org/ ☄ 2010-04-27 yes i agree that google care, and do something about this.The click spam feature was added recently, perhaps 6 months ago, that indicates they do care, even if it is not that effective.also, how effective it is depends of course on how many people report spam. For groups like comp.lang.lisp, many are old timers, don't use google, and the readership is already comparatively very small. So, it can get worse.another thing might be interesting is that the spam rate seems to depends on the newsgr…

Emacs Shortcut to Delete Whole Line

Perm url with updates: http://xahlee.org/emacs/emacs_delete_whole_line.htmlEmacs Shortcut to Delete Whole LineXah Lee, 2010-04-28I've been using the ErgoEmacs Keybinding for 3 years, and have spent hundreds of hours thinking about efficiency of commands and shortcut choices.Today, it came to my mind that a shortcut to delete the whole line, is actually quite useful. Because, i noticed that i'm tired of having to move cursor to beginning of line first then kill. The problem is made worse by the fact that kill-line does not kill the line ending. So, to delete a line in emacs, you have to move cursor to the beginning first, then do kill-line twice, a total of 3 operations. In GNU Emacs, the key presses are C-a, then C-k, C-k. (In vi, it is just a single operation, done by pressing “dd”.)Define a Shortcut to Delete Whole LineSo, personally, i made a shortcut to kill the whole line. Like this: (global-set-key (kbd "M-9") 'kill-whole-line) This is actually part of a …

AutoHotKey Key Notations

Perm url with updates: http://xahlee.org/mswin/autohotkey_key_notations.htmlAutoHotKey Key NotationsXah Lee, 2010-04-28This page is a list of notations for AutoHotKey. If you not sure what AutoHotKey is, see: AutoHotKey Basics.Basic Key SyntaxHere's the basic syntax. This should be enough most of your needs. #n::Run Notepad ; this means the Win+n !n::Run Notepad ; this means Alt+n ^n::Run Notepad ; this means Ctrl+n F6::Run Notepad ; F6 ^F6::Run Notepad ; Ctrl+F6 ^!n::Run Notepad ; Ctrl+Alt+n Key SyntaxHere's a complete list of AutoHotKey's key syntax.F KeysThe syntax is F1, F2, F3... etc, to F24.Space, Tab, Enter, Home, End, Arrows ... Space Tab Enter (or Return) Escape (or Esc) Backspace (or BS) Delete (or Del) Insert (or Ins) Home End PgUp PgDn Up Down Left Right ScrollLock CapsLock PrintScreen CtrlBreak Pause Break — Since this is synonymous with Pause, use ^CtrlBreak in hotkeys instead of ^Pause or ^Break. Help — does not exist on most keybo…

meta gaming company: Steampowered.com

Perm url with updates: http://xahlee.org/sl/blog.htmlThinking about it, i actually haven't played ANY massive online games except Second Life. In fact, the last 2 games i remember played on PC is American McGee's Alice, and that is in around 2000.(am 42, and in my teens and 20s and 30s, i surely have played lots of video games. Basically, my gaming behavior is like addiction. When i got into a game, i'd play it for weeks EVERY MINUTE WHEN I'M AWAKE, even skipping food, rush to bathroom, or went sleep deprivation, till i mastered it thoroughly. Then, usually guilt overcame me for playing video game so much, and i'd swear never to play game again. I'd not play another video game for half a year or a year, or longer especially when i get older.)Though, in the past 3 years while spend several hours in Second Life almost daily, i learned tremendously about the online gaming community today. (note that massive multi-player online games is only a phenomenon say after …

How to Use Windows Search

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Perm url with updates: http://xahlee.org/mswin/Windows_search.htmlHow to Use Windows SearchXah Lee, 2010-04-27, 2010-08-20This page explains how to use Windows Search, and also some tech details for programers.Had quiet a fruitful reading on Windows Search. Here's are some interesting highlighs. (am using Windows Vista)Using Windows SearchWays to Start Windows SearchThere are several ways to bring up the search box.Press the Win key. Type search word, then press Enter.“Win+F” brings up the search panel.The upper right corner of folder window. (press “Win+E” to bring up a folder, then press “Alt+D” to put focus on path field, then press Tab to go to the search field.)The Start Menu has a search box. You can use it to search or quickly launch programs. Advanced Search and OptionsSearch options. To get options, do a search, then click on the Advanced Search on the upper right. Search location can be set. Also, what type of file to search. Which files to index. Or, whether to search on…

mac os x: secure delete, tar/gzip with resource fork

Discovered that on Mac Os X 10.6, tar, gzip, gunzip preserves resource fork by default. Updated at: Mac OS X Resource Fork and Command Line Tips.Discovered that on the Mac, to securely delete files, just use the builtin command srm, like this: “srm -r -s dir_path”. For detail, see: Secure Deletion, File Shredding, on Windows, Linux, Mac.

What is the Difference of Formalism, Logicism, Axiomatic System?

Perm url with updates: http://xahlee.org/cmaci/notation/formalism_logicism_axiomatic_math.htmlWhat is the Difference of Symbolic Logic System, Hilbert's Formalism, Russell's Logicism, Axiomatic System?Xah Lee, 2007-08-21, 2010-04-26This short essay explains the difference of Symbolic Logic System, (Hilbert's) Formalism, in today's math foundation context, and the meaning of today's common math practice of using axioms as a foundation, its relation to logicism and formalism.LogicismLogicism, a Symbolic Logic System as foundation of math, is today known as Mathematical Logic. It went thru several names in recent history as the subject matured: predicate logic, first order logic, symbolic logic, mathematical logic. As such, it is effectively a study of Formal Language systems. A Formal Language basically means starting with some “symbol strings” called “axioms”, and with given rules to derive more symbol strings called “theorems”.FormalismFormalism in our context, i…

How to Define Optional Parameters in Emacs Lisp

Perm url with updates: http://xahlee.org/emacs/elisp_optional_params.htmlHow to Define Optional Parameters in Emacs LispXah Lee, 2010-04-25A little tip on emacs function's parameter features and syntax. If you don't know the basic of elisp, you should read Emacs Lisp Basics first.Use “&optional” for Optional ParametersEmacs's function parameter's features and syntax is very basic. It is simply a list of items. If you want optional parameters, just add “&optional” in your parameter. Any parameter after that will be optional. Here is a example:;; defining a function with 2 optional params cc and dd (defunmyfun (aa bb &optional cc dd) ;... ) When you call this function, aa and bb are required, cc and dd are optional. When a optional parameter is not given, its value is “nil”. If you want to give a argument to some optional parameters but not all, use “nil” for those you don't care. For example, to call “myfun” in the above with a argument for “dd” but you …

Linden Labs Viewer Policy and New Viewers

2010-04-25 Linden Labs has created a new policy about third party viewers. Basically, viewers that does not respect their Term Of Service policy or does export items without respecting the permission system will no longer be able to login to Linden Labs's server. This policy is enforced starting on 2010-05-01. For detail, see: secondlife.com Policy on Third-Party Viewers.They also have a page listing approved viewers at http://viewerdirectory.secondlife.com/. Currently there are 7 third-party ones. Some of these viewers have interesting features. For example, a text based viewer, viewer for cellphone (iPod, iPhone, Android), viewer for film makers and photographers (basically high-end rendering).Note that Emerald viewer is compliant. I highly recommend the Emerald Viewer for power players.