Minecraft MOD in Clojure

http://github.com/ujihisa/cloft

I've been writing Clojure for this Minecraft server MOD. This MOD, cloft, uses Bukkit API and is compatible with Minecraft client version 1.3.1+, including the latest stable version 1.3.2.

This MOD was originally based on clj-minecraft made by Deon Moolman.

I'm also running my own minecraft server with using cloft. If you are interested in playing, feel free to ask me on Twitter.

ZeroMQ Versions and Bindings

ZeroMQ has two major versions; 2.x.y and 3.x.y. Even though the latter is still release candidate, people are already using it. The problem is that these two versions don't have compatibility. If one system uses version 3.x.y, whole other systems which talk to the system have to use 3.x.y.

There are some binding libraries for each programming languages. Note that some of them don't support one of the versions. The below is the list as of today.

• Haskell
  • zeromq-haskell: 2.1.x
  • zeromq-haskell3: 3.1.x
  • just use cabal to install them
• Clojure
  • (Not directly for Clojure but for JVM languages in general)
  • jzmq: both 2.x.y and 3.x.y
  • there are no official clojar/maven/apt/portage packages. one for gentoo is here
• Scala
  • zeromq-scala-binding: 2.1.x
    • (akka-zeromq uses it)
  • jzmq: both 2.x.y and 3.x.y
    • (ditto in Clojure)
• Ruby
  • rbzmq: 2.x.y
• Python
  • pyzmq: 2.x.x (experimentally 3.x.x)

Use Haskell, Clojure, Scala or Python to use ZeroMQ even if you use zeromq version 2 just in case at least one system uses version 3. If you need to use Ruby, just use JRuby to use jzmq. It's not very easy to install jzmq, but if you are using Gentoo, it's easy.

Octal or not Octal

A number literal with begins with 0 differs between programming languages. For example, a programming language considers 015 as 13, or as 15 just by ignoring the first 0, or even throws an error.

I categorized some programming languages by the view.

• 015 == 13
  • Clojure
  • Scala
  • Java
  • Ruby
  • C
  • Vim script
  • JavaScript
• 015 == 15
  • Haskell
  • Scheme
  • Emacs Lisp
  • Lua
  • Common Lisp
• Exception
  • Python
  • CoffeeScript

Concurrent PI-Calculator in Clojure

Inspired by a tutorial about akka tutorial in Scala about making a concurrent PI calculator, I made similar on in Clojure without actor model but just with thread and atom.

(ns pi.core
  (:import [java.util.concurrent Executors])
  (:gen-class))

(def sum (partial reduce +))

(defn f [n]
  (/ (if (even? n) 1 -1) (inc (* 2 n))))

(defn solver1 [n]
  (double (* 4 (sum (map f (range 0 n))))))

(defn solver2 [n]
  (def a (atom 0))
  (def tasks
    (let [unit (/ n 4)]
      (for [m (range 0 4)]
        (fn []
          (swap! a (partial + (sum (map f (range (* unit m) (* unit (inc m)))))))))))

  (let [pool (Executors/newFixedThreadPool (count tasks))]
    (doseq [f (.invokeAll pool tasks)]
      (.get f))
    (.shutdown pool))
  (double (* 4 @a)))

(defn -main []
  (let [n 2000]
    (prn (solver1 n))
    (prn (solver2 n))))

Commenting out the line of solver1/solver2, I got the following results on my 2-core with hyper-threading machine; virtually it's 4 core machine.

solver1

real 3.80
user 4.66
sys 0.09
3.141092653621043

solver2

real 2.01
user 3.44
sys 0.05
3.141092653621043

Comparing to the sequential version, the concurrent version was almost 2 times faster.

IBus-Mozc for Kana Input on US Keyboard Layout

There are two major input methods in Japanese language; roma-input and kana-input (*1). Roma-input layouts in popular implementations are same while kana-input layouts are different among implementations for some reason when it's on US Keyboard layout.

I'm a kana typer and a user of US Keyboard Layout. Kana layout of Mac OS X Kotoeri layout and kana layout of ibus-mozc are very different. I had used Kotoeri for a long time, so I decided to change the layout of mozc, but mozc doesn't have an interface to change the layout.

I wrote a patch to make mozc same to Kotoeri's.

kana-layout.patch:

Index: unix/ibus/key_translator.cc
===================================================================
--- unix/ibus/key_translator.cc (revision 94)
+++ unix/ibus/key_translator.cc (working copy)
@@ -254,100 +254,100 @@
   // to Right Shift).
   { '\\', "", "" },
 }, kana_map_us[] = {
-  { '`' , "\xe3\x82\x8d", "\xe3\x82\x8d" },  // "ろ", "ろ"
-  { '~' , "\xe3\x82\x8d", "\xe3\x82\x8d" },  // "ろ", "ろ"
-  { '1' , "\xe3\x81\xac", "\xe3\x81\xac" },  // "ぬ", "ぬ"
-  { '!' , "\xe3\x81\xac", "\xe3\x81\xac" },  // "ぬ", "ぬ"
-  { '2' , "\xe3\x81\xb5", "\xe3\x81\xb5" },  // "ふ", "ふ"
+  { '$' , "\xe3\x81\x85", "\xe3\x81\x85" },  // "ぅ", "ぅ"
+  { '(' , "\xe3\x82\x87", "\xe3\x82\x87" },  // "ょ", "ょ"
+  { ',' , "\xe3\x81\xad", "\xe3\x81\xad" },  // "ね", "ね"
+  { '0' , "\xe3\x82\x8f", "\xe3\x82\x8f" },  // "わ", "わ"
+  { '4' , "\xe3\x81\x86", "\xe3\x81\x86" },  // "う", "う"
+  { '8' , "\xe3\x82\x86", "\xe3\x82\x86" },  // "ゆ", "ゆ"
+  { '<' , "\xe3\x80\x81", "\xe3\x80\x81" },  // "、", "、"
   { '@' , "\xe3\x81\xb5", "\xe3\x81\xb5" },  // "ふ", "ふ"
-  { '3' , "\xe3\x81\x82", "\xe3\x81\x81" },  // "あ", "ぁ"
-  { '#' , "\xe3\x81\x82", "\xe3\x81\x81" },  // "あ", "ぁ"
-  { '4' , "\xe3\x81\x86", "\xe3\x81\x85" },  // "う", "ぅ"
-  { '$' , "\xe3\x81\x86", "\xe3\x81\x85" },  // "う", "ぅ"
-  { '5' , "\xe3\x81\x88", "\xe3\x81\x87" },  // "え", "ぇ"
-  { '%' , "\xe3\x81\x88", "\xe3\x81\x87" },  // "え", "ぇ"
-  { '6' , "\xe3\x81\x8a", "\xe3\x81\x89" },  // "お", "ぉ"
-  { '^' , "\xe3\x81\x8a", "\xe3\x81\x89" },  // "お", "ぉ"
-  { '7' , "\xe3\x82\x84", "\xe3\x82\x83" },  // "や", "ゃ"
-  { '&' , "\xe3\x82\x84", "\xe3\x82\x83" },  // "や", "ゃ"
-  { '8' , "\xe3\x82\x86", "\xe3\x82\x85" },  // "ゆ", "ゅ"
-  { '*' , "\xe3\x82\x86", "\xe3\x82\x85" },  // "ゆ", "ゅ"
-  { '9' , "\xe3\x82\x88", "\xe3\x82\x87" },  // "よ", "ょ"
-  { '(' , "\xe3\x82\x88", "\xe3\x82\x87" },  // "よ", "ょ"
-  { '0' , "\xe3\x82\x8f", "\xe3\x82\x92" },  // "わ", "を"
-  { ')' , "\xe3\x82\x8f", "\xe3\x82\x92" },  // "わ", "を"
-  { '-' , "\xe3\x81\xbb", "\xe3\x83\xbc" },  // "ほ", "ー"
-  { '_' , "\xe3\x81\xbb", "\xe3\x83\xbc" },  // "ほ", "ー"
-  { '=' , "\xe3\x81\xb8", "\xe3\x81\xb8" },  // "へ", "へ"
-  { '+' , "\xe3\x81\xb8", "\xe3\x81\xb8" },  // "へ", "へ"
-  { 'q' , "\xe3\x81\x9f", "\xe3\x81\x9f" },  // "た", "た"
-  { 'Q' , "\xe3\x81\x9f", "\xe3\x81\x9f" },  // "た", "た"
-  { 'w' , "\xe3\x81\xa6", "\xe3\x81\xa6" },  // "て", "て"
-  { 'W' , "\xe3\x81\xa6", "\xe3\x81\xa6" },  // "て", "て"
-  { 'e' , "\xe3\x81\x84", "\xe3\x81\x83" },  // "い", "ぃ"
-  { 'E' , "\xe3\x81\x84", "\xe3\x81\x83" },  // "い", "ぃ"
-  { 'r' , "\xe3\x81\x99", "\xe3\x81\x99" },  // "す", "す"
-  { 'R' , "\xe3\x81\x99", "\xe3\x81\x99" },  // "す", "す"
+  { 'D' , "\xe3\x81\x97", "\xe3\x81\x97" },  // "し", "し"
+  { 'H' , "\xe3\x81\x8f", "\xe3\x81\x8f" },  // "く", "く"
+  { 'L' , "\xe3\x82\x8a", "\xe3\x82\x8a" },  // "り", "り"
+  { 'P' , "\xe3\x81\x9b", "\xe3\x81\x9b" },  // "せ", "せ"
+  { 'T' , "\xe3\x81\x8b", "\xe3\x81\x8b" },  // "か", "か"
+  { 'X' , "\xe3\x81\x95", "\xe3\x81\x95" },  // "さ", "さ"
+  { '\\' , "\xe3\x81\xb8", "\xe3\x81\xb8" },  // "へ", "へ"
+  { '`' , "\xef\xbd\x80", "\xef\xbd\x80" },  // "｀", "｀"
+  { 'd' , "\xe3\x81\x97", "\xe3\x81\x97" },  // "し", "し"
+  { 'h' , "\xe3\x81\x8f", "\xe3\x81\x8f" },  // "く", "く"
+  { 'l' , "\xe3\x82\x8a", "\xe3\x82\x8a" },  // "り", "り"
+  { 'p' , "\xe3\x81\x9b", "\xe3\x81\x9b" },  // "せ", "せ"
   { 't' , "\xe3\x81\x8b", "\xe3\x81\x8b" },  // "か", "か"
-  { 'T' , "\xe3\x81\x8b", "\xe3\x81\x8b" },  // "か", "か"
-  { 'y' , "\xe3\x82\x93", "\xe3\x82\x93" },  // "ん", "ん"
-  { 'Y' , "\xe3\x82\x93", "\xe3\x82\x93" },  // "ん", "ん"
-  { 'u' , "\xe3\x81\xaa", "\xe3\x81\xaa" },  // "な", "な"
-  { 'U' , "\xe3\x81\xaa", "\xe3\x81\xaa" },  // "な", "な"
-  { 'i' , "\xe3\x81\xab", "\xe3\x81\xab" },  // "に", "に"
-  { 'I' , "\xe3\x81\xab", "\xe3\x81\xab" },  // "に", "に"
-  { 'o' , "\xe3\x82\x89", "\xe3\x82\x89" },  // "ら", "ら"
+  { 'x' , "\xe3\x81\x95", "\xe3\x81\x95" },  // "さ", "さ"
+  { '|' , "\xe3\x82\x8d", "\xe3\x82\x8d" },  // "ろ", "ろ"
+  { '#' , "\xe3\x81\x81", "\xe3\x81\x81" },  // "ぁ", "ぁ"
+  { '\'' , "\xe3\x81\x91", "\xe3\x81\x91" },  // "け", "け"
+  { '+' , "\xe3\x80\x8c", "\xe3\x80\x8c" },  // "「", "「"
+  { '/' , "\xe3\x82\x81", "\xe3\x82\x81" },  // "め", "め"
+  { '3' , "\xe3\x81\x82", "\xe3\x81\x82" },  // "あ", "あ"
+  { '7' , "\xe3\x82\x84", "\xe3\x82\x84" },  // "や", "や"
+  { ';' , "\xe3\x82\x8c", "\xe3\x82\x8c" },  // "れ", "れ"
+  { '?' , "\xe3\x83\xbb", "\xe3\x83\xbb" },  // "・", "・"
+  { 'C' , "\xe3\x81\x9d", "\xe3\x81\x9d" },  // "そ", "そ"
+  { 'G' , "\xe3\x81\x8d", "\xe3\x81\x8d" },  // "き", "き"
+  { 'K' , "\xe3\x81\xae", "\xe3\x81\xae" },  // "の", "の"
   { 'O' , "\xe3\x82\x89", "\xe3\x82\x89" },  // "ら", "ら"
-  { 'p' , "\xe3\x81\x9b", "\xe3\x81\x9b" },  // "せ", "せ"
-  { 'P' , "\xe3\x81\x9b", "\xe3\x81\x9b" },  // "せ", "せ"
+  { 'S' , "\xe3\x81\xa8", "\xe3\x81\xa8" },  // "と", "と"
+  { 'W' , "\xe3\x81\xa6", "\xe3\x81\xa6" },  // "て", "て"
   { '[' , "\xe3\x82\x9b", "\xe3\x82\x9b" },  // "゛", "゛"
-  { '{' , "\xe3\x82\x9b", "\xe3\x82\x9b" },  // "゛", "゛"
-  { ']' , "\xe3\x82\x9c", "\xe3\x80\x8c" },  // "゜", "「"
-  { '}' , "\xe3\x82\x9c", "\xe3\x80\x8c" },  // "゜", "「"
-  { '\\', "\xe3\x82\x80", "\xe3\x80\x8d" },  // "む", "」"
-  { '|' , "\xe3\x82\x80", "\xe3\x80\x8d" },  // "む", "」"
-  { 'a' , "\xe3\x81\xa1", "\xe3\x81\xa1" },  // "ち", "ち"
-  { 'A' , "\xe3\x81\xa1", "\xe3\x81\xa1" },  // "ち", "ち"
+  { '_' , "\xe3\x81\xbb", "\xe3\x81\xbb" },  // "ほ", "ほ"
+  { 'c' , "\xe3\x81\x9d", "\xe3\x81\x9d" },  // "そ", "そ"
+  { 'g' , "\xe3\x81\x8d", "\xe3\x81\x8d" },  // "き", "き"
+  { 'k' , "\xe3\x81\xae", "\xe3\x81\xae" },  // "の", "の"
+  { 'o' , "\xe3\x82\x89", "\xe3\x82\x89" },  // "ら", "ら"
   { 's' , "\xe3\x81\xa8", "\xe3\x81\xa8" },  // "と", "と"
-  { 'S' , "\xe3\x81\xa8", "\xe3\x81\xa8" },  // "と", "と"
-  { 'd' , "\xe3\x81\x97", "\xe3\x81\x97" },  // "し", "し"
-  { 'D' , "\xe3\x81\x97", "\xe3\x81\x97" },  // "し", "し"
-  { 'f' , "\xe3\x81\xaf", "\xe3\x81\xaf" },  // "は", "は"
+  { 'w' , "\xe3\x81\xa6", "\xe3\x81\xa6" },  // "て", "て"
+  { '{' , "\xe3\x80\x8d", "\xe3\x80\x8d" },  // "」", "」"
+  { '"' , "\xe3\x82\x8d", "\xe3\x82\x8d" },  // "ろ", "ろ"
+  { '&' , "\xe3\x82\x83", "\xe3\x82\x83" },  // "ゃ", "ゃ"
+  { '*' , "\xe3\x82\x85", "\xe3\x82\x85" },  // "ゅ", "ゅ"
+  { '.' , "\xe3\x82\x8b", "\xe3\x82\x8b" },  // "る", "る"
+  { '2' , "\xe3\x81\xb5", "\xe3\x81\xb5" },  // "ふ", "ふ"
+  { '6' , "\xe3\x81\x8a", "\xe3\x81\x8a" },  // "お", "お"
+  { ':' , "\xe3\x82\x8c", "\xe3\x82\x8c" },  // "れ", "れ"
+  { '>' , "\xe3\x80\x82", "\xe3\x80\x82" },  // "。", "。"
+  { 'B' , "\xe3\x81\x93", "\xe3\x81\x93" },  // "こ", "こ"
   { 'F' , "\xe3\x81\xaf", "\xe3\x81\xaf" },  // "は", "は"
-  { 'g' , "\xe3\x81\x8d", "\xe3\x81\x8d" },  // "き", "き"
-  { 'G' , "\xe3\x81\x8d", "\xe3\x81\x8d" },  // "き", "き"
-  { 'h' , "\xe3\x81\x8f", "\xe3\x81\x8f" },  // "く", "く"
-  { 'H' , "\xe3\x81\x8f", "\xe3\x81\x8f" },  // "く", "く"
-  { 'j' , "\xe3\x81\xbe", "\xe3\x81\xbe" },  // "ま", "ま"
   { 'J' , "\xe3\x81\xbe", "\xe3\x81\xbe" },  // "ま", "ま"
-  { 'k' , "\xe3\x81\xae", "\xe3\x81\xae" },  // "の", "の"
-  { 'K' , "\xe3\x81\xae", "\xe3\x81\xae" },  // "の", "の"
-  { 'l' , "\xe3\x82\x8a", "\xe3\x82\x8a" },  // "り", "り"
-  { 'L' , "\xe3\x82\x8a", "\xe3\x82\x8a" },  // "り", "り"
-  { ';' , "\xe3\x82\x8c", "\xe3\x82\x8c" },  // "れ", "れ"
-  { ':' , "\xe3\x82\x8c", "\xe3\x82\x8c" },  // "れ", "れ"
-  { '\'', "\xe3\x81\x91", "\xe3\x81\x91" },  // "け", "け"
-  { '\"', "\xe3\x81\x91", "\xe3\x81\x91" },  // "け", "け"
-  { 'z' , "\xe3\x81\xa4", "\xe3\x81\xa3" },  // "つ", "っ"
-  { 'Z' , "\xe3\x81\xa4", "\xe3\x81\xa3" },  // "つ", "っ"
-  { 'x' , "\xe3\x81\x95", "\xe3\x81\x95" },  // "さ", "さ"
-  { 'X' , "\xe3\x81\x95", "\xe3\x81\x95" },  // "さ", "さ"
-  { 'c' , "\xe3\x81\x9d", "\xe3\x81\x9d" },  // "そ", "そ"
-  { 'C' , "\xe3\x81\x9d", "\xe3\x81\x9d" },  // "そ", "そ"
-  { 'v' , "\xe3\x81\xb2", "\xe3\x81\xb2" },  // "ひ", "ひ"
+  { 'N' , "\xe3\x81\xbf", "\xe3\x81\xbf" },  // "み", "み"
+  { 'R' , "\xe3\x81\x99", "\xe3\x81\x99" },  // "す", "す"
   { 'V' , "\xe3\x81\xb2", "\xe3\x81\xb2" },  // "ひ", "ひ"
+  { 'Z' , "\xe3\x81\xa3", "\xe3\x81\xa3" },  // "っ", "っ"
+  { '^' , "\xe3\x81\x89", "\xe3\x81\x89" },  // "ぉ", "ぉ"
   { 'b' , "\xe3\x81\x93", "\xe3\x81\x93" },  // "こ", "こ"
-  { 'B' , "\xe3\x81\x93", "\xe3\x81\x93" },  // "こ", "こ"
+  { 'f' , "\xe3\x81\xaf", "\xe3\x81\xaf" },  // "は", "は"
+  { 'j' , "\xe3\x81\xbe", "\xe3\x81\xbe" },  // "ま", "ま"
   { 'n' , "\xe3\x81\xbf", "\xe3\x81\xbf" },  // "み", "み"
-  { 'N' , "\xe3\x81\xbf", "\xe3\x81\xbf" },  // "み", "み"
+  { 'r' , "\xe3\x81\x99", "\xe3\x81\x99" },  // "す", "す"
+  { 'v' , "\xe3\x81\xb2", "\xe3\x81\xb2" },  // "ひ", "ひ"
+  { 'z' , "\xe3\x81\xa4", "\xe3\x81\xa4" },  // "つ", "つ"
+  { '~' , "\xe3\x80\x9c", "\xe3\x80\x9c" },  // "〜", "〜"
+  { '!' , "\xe3\x81\xac", "\xe3\x81\xac" },  // "ぬ", "ぬ"
+  { '%' , "\xe3\x81\x87", "\xe3\x81\x87" },  // "ぇ", "ぇ"
+  { ')' , "\xe3\x82\x92", "\xe3\x82\x92" },  // "を", "を"
+  { '-' , "\xe3\x81\xbb", "\xe3\x81\xbb" },  // "ほ", "ほ"
+  { '1' , "\xe3\x81\xac", "\xe3\x81\xac" },  // "ぬ", "ぬ"
+  { '5' , "\xe3\x81\x88", "\xe3\x81\x88" },  // "え", "え"
+  { '9' , "\xe3\x82\x88", "\xe3\x82\x88" },  // "よ", "よ"
+  { '=' , "\xe3\x82\x9c", "\xe3\x82\x9c" },  // "゜", "゜"
+  { 'A' , "\xe3\x81\xa1", "\xe3\x81\xa1" },  // "ち", "ち"
+  { 'E' , "\xe3\x81\x83", "\xe3\x81\x83" },  // "ぃ", "ぃ"
+  { 'I' , "\xe3\x81\xab", "\xe3\x81\xab" },  // "に", "に"
+  { 'M' , "\xe3\x82\x82", "\xe3\x82\x82" },  // "も", "も"
+  { 'Q' , "\xe3\x81\x9f", "\xe3\x81\x9f" },  // "た", "た"
+  { 'U' , "\xe3\x81\xaa", "\xe3\x81\xaa" },  // "な", "な"
+  { 'Y' , "\xe3\x82\x93", "\xe3\x82\x93" },  // "ん", "ん"
+  { ']' , "\xe3\x82\x80", "\xe3\x82\x80" },  // "む", "む"
+  { 'a' , "\xe3\x81\xa1", "\xe3\x81\xa1" },  // "ち", "ち"
+  { 'e' , "\xe3\x81\x84", "\xe3\x81\x84" },  // "い", "い"
+  { 'i' , "\xe3\x81\xab", "\xe3\x81\xab" },  // "に", "に"
   { 'm' , "\xe3\x82\x82", "\xe3\x82\x82" },  // "も", "も"
-  { 'M' , "\xe3\x82\x82", "\xe3\x82\x82" },  // "も", "も"
-  { ',' , "\xe3\x81\xad", "\xe3\x80\x81" },  // "ね", "、"
-  { '<' , "\xe3\x81\xad", "\xe3\x80\x81" },  // "ね", "、"
-  { '.' , "\xe3\x82\x8b", "\xe3\x80\x82" },  // "る", "。"
-  { '>' , "\xe3\x82\x8b", "\xe3\x80\x82" },  // "る", "。"
-  { '/' , "\xe3\x82\x81", "\xe3\x83\xbb" },  // "め", "・"
-  { '?' , "\xe3\x82\x81", "\xe3\x83\xbb" },  // "め", "・"
+  { 'q' , "\xe3\x81\x9f", "\xe3\x81\x9f" },  // "た", "た"
+  { 'u' , "\xe3\x81\xaa", "\xe3\x81\xaa" },  // "な", "な"
+  { 'y' , "\xe3\x82\x93", "\xe3\x82\x93" },  // "ん", "ん"
+  { '}' , "\xe3\x83\xbc", "\xe3\x83\xbc" },  // "ー", "ー"
 };

 }  // namespace
Index: unix/ibus/mozc_engine.cc
===================================================================
--- unix/ibus/mozc_engine.cc    (revision 94)
+++ unix/ibus/mozc_engine.cc    (working copy)
@@ -542,8 +542,7 @@
 #endif

   // TODO(yusukes): use |layout| in IBusEngineDesc if possible.
-  const bool layout_is_jp =
-      !g_strcmp0(ibus_engine_get_name(engine), "mozc-jp");
+  const bool layout_is_jp = 0;

   commands::KeyEvent key;
   if (!key_translator_->Translate(

Here I also made an ebuild for the latest ibus-mozc on gentoo portage. You can just use it if you are a Gentoo user.

http://ujihisa.shiracha.net/static/ibus-mozc-1.3.975.102.tgz

• *1 There are more variety of other input methods like thumb-shift or kyuuri-kai.

Realtek RTL8191S WLAN Adapter on Gentoo

I bought a wireless network adapter for my Gentoo desktop computer. It's a usb dongle and it says it's Linux-compatible.

RealTek 8191SU

How to use:

Device Drivers ->
  Staging drivers ->
    RealTek RTL8712U (RTL8192SU) Wireless LAN NIC driver

In the menuconfig.

AutoKey Rocks

Mac OS X has a built-in keyboard shortcut configuration tool in Preferences. You can set both global key bindings and application-specific key bindings.

I had used this to use Cmd key more often than Ctrl key. For example Google Chrome has default key mappings to go to the next tab by <ctrl-tab> and to the previous tab by <shift-ctrl-tab>. They break your left pinky easily. I mapped them ad <Cmd-j> and <Cmd-k>. That helped the finger.

But there is no such great built-in tool in the Linux world neither in Gnome nor KDE. There is a Keyboard Shortcuts in Preference of Gnome, but it's only for Gnome apps.

AutoKey

AutoKey is a similar tool to the Mac OS X built-in keybinding configuration tool. The differences are (1) AutoKey doesn't map a key to a function in the application's menu and (2) AutoKey enables you to run arbitrary scripts.

It's very easy to install on Debian family distributions such as Ubuntu. Gentoo, on the other hand, has an overlay that has autokey-gtk package, but it's broken. You have to get the source code and build it. It also requires you to install some dependencies manually, but it works.

autokey-gtk on gentoo

(Added on Jan 24 2012)

There is an issue in autokey that you cannot exclude a window easily. See the end of this discussion to solve it. http://groups.google.com/group/autokey-users/browse_thread/thread/658ad02cfbde8788