Blogs @ Steinway Wu

Vermont Roadtrip

Fix Duplicated Icons in Plank/Docky

I ran into duplicated Chrome icons with Plank on Ubuntu, and here's the solution I found: http://kb.openstudioproject.com/content/fix-double-google-chrome-icon-docky-and-plank In short, Open /usr/share/applications/google-chrome.desktop with root permissions. Under each section ([Desktop Entry], [NewWindow Shortcut Group] and [NewIncognito Shortcut

tip

WikiWand

Just to spread the word. WikiWand is a fancier-looking and eaiser-to-use Wikipedia theme.

ats

Sorts, Statics, and Dynamics in ATS

Note: this is moved from my old blog. This is an interesting talk given by my adviser Prof. Xi. And I will try my best to put the ideas here in a proper way. Type Systems in a Word Type systems are systems about

lambda calculas

The Y Combinator

Note: this is moved from my old blog. Currently, I am learning Lambda Calculus, and the Y combinator. And I am going to talk about why people need such kind of combinators, but how it is derived will not be covered since there are

operating system

CALL, LEA, MOV, and Link Edit

Note: This is moved from my old blog. When writing your own real mode boot strap, you have to deal with addresses correctly. My friends Zhuoqun and I have cleared some problems encountered, and I will note them here. Note that this is my

tips

Repeat a SQL Multiple Times with db2batch

Just enclose the SQL statements within --#BGBLK and --#EOBLK and feed it with a repeat-count as shown in input.sql. Then run db2batch -d DATABASE_NAME -f input.sql $(".readme").parent().parent().remove() Reference: IBM Knowledge Center: http://www-01.ibm.com/support/

tips

One-liner to Find Out Available Ports in /etc/services

Just follow the Gist $(".readme").parent().parent().remove()

parsing

Operator Precedence Climbing Parsing with User-defined Operators

ATS supports user defined symbols with custom fixity and precedence. The patopt compiler will do a dedicated pass to resolve fixity before all other passes. I tried to build a parser that supports the samething using Antlr. After several tries, I finally did it

tips

Quick Tips: SublimeText Auto-line-wrap in Distraction Mode

To enable automatic line wrap (instead of fixed line wrap) in SublimeText distraction mode: Preference -> Settings - More -> Distraction Free - User Add the following line "wrap_width" : 0 The resulting config may look like this: { "wrap_

docker

OpenGrok + Docker = Code Reading Expert

When sitting down in front of a new project, I alwasy find it hard to start because code reading is not easy at all. Sublimetext + ctags does help, but not perfect. OpenGrok is good but needs configure. So here's the solution: put OpenGrok in

mysql

Code Reading Notes - MySQL Cluster

The partitioning code in MySQL Cluster is a totally different story from the MySQL Server partition plugin. The partitioning is handled natively by the Network DataBase storage engine. As mentioned in part 1 and part 2, MySQL Server still needs to parse the SQL

mysql

Code Reading Notes - MySQL Server Partitioning II

Please read Part I first When we come to altering table, there is a lot happening under the hood. You can find a list of ALTER TABLE ... PARTITION ... here. And this is a short list: ALTER TABLE ... | ADD PARTITION (partition_definition) | DROP PARTITION partition_

mysql

Code Reading Notes - MySQL Server Partitioning

MySQL provides a general interface of storage engine handlers. A variety of implementations are built into MySQL, including MyISAM, InnoDB and Partitioning. Most of storage engines do not support partitioning natively [ref]. Therefore Mikael Ronström implemented a partitioning storage engine on top of existing

socket.io

Socket.IO Client Forcing New Connection

As indicated here on Github, socket.io-client is mutiplexing Managers. If you want to force new connections every time you fire io.connect(), you should pass in {forceNew: true} as one of the options. Update: BTW, I recommend using Primus.io, "the creator

tips

Using Boston University VPN on Ubuntu

Installing Cisco VPN protocal sudo apt-get install network-manager-vpnc Setup VPN parameters in the network manager Open Network Connections Add new VPN connection and select Cisco VPN Type in parameters FieldValue User Nameyour username User Passwordyour password Group NameBostonU Group PasswordBostonU

ats

Enigma Machine

Enigma Machine is a family of enciphering and deciphering machines invented and used in WWI and WWII, and later hacked by scientiests including Alan Turing. There are different versions and settings of Enigma machine, but essentially, it is such a function: \\( E(x) = P^

ats

Lazy Evaluation

(This is a post for CS320 Boston University.) In most programming languages, expressions are evaluated right after it is bound to a variable. This is eager evaluation. However, you can't always evaluate an expression immediately. // pseudo code val natlist = 0 :: 1 :: 2 :: .... An infinite

ats

A Docker Image for Quick-starting ATS

I've tried docker today, and it's pretty useful for sharing a development environment. docker is an open source project to pack, ship and run any application as a lightweight container. Docker allows me to build a complete environment using just a single command (and

ats

SublimeText Syntax Highlight for ATS

The first stable version of ATS syntax highlight for SublimeText has been released here. I have already submitted it to the official package control channel. Hopefully you can get it from your commond line soon. For now, please download the ats.tmLanguage file into

tips

Using the New RTD Theme

readthedocs.org has a new theme that looks much better than before. A description could be found here. All you need to do is to add RTD_NEW_THEME = True to your conf.py. Check out a live demo here.

logic

A Summary of SMT-LIB Logic 2.0

(I moved this from my old blog.) I was working on integrating two SMT solvers with Wenxin Feng, therefore it is necessary to understand the SMT-LIB 2.0 logic, which can be used as an input language for both solvers (AltErgo, CVC4). Part of

ats

Minimax Searching

(This is a post for CS320 Boston University) Minimax is a decision rule used in game theory for minimizing the possible loss for a worst case (maximum loss) scenario [wiki]. Alternatively, it can be thought of as maximizing the minimum gain. It is usually

ats

Matrices in ATS

(This is a post for CS320 Boston University.) Please take a look at this. Get yourself familiar with matirx operations and high order functions. Also, it is a good example of functions/closures. A brief summary of library functions: http://www.ats-lang.org/LIBRARY/

cs320

Free Variables, Functions and Closures

(This is a post for CS320 Boston University.) In order to discuss environments, closures and functions, I would like to discuss free and bound variables first. Free/Bound Variables Take this as an example lam (x) => x + y Here we call x, x,