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Resolve ambiguities in antlr v3

frank — Thu, 10 Jun 2010 20:15:28 +0000

When there is ambiguities in writing antlr grammar, there are different ways to solve it.

1. Simply avoid them. This is the ideal way when it’s possible.

2. Turn on backtracking, which is most inefficient way.

3. Use left factoring.

4. Use syntax predicates.

For some samples, check it out at http://www.antlr.org/wiki/display/ANTLR3/How+to+remove+global+backtracking+from+your+grammar

The format of sytnax predicate is close to semantic predicates. There are 3 types of them:

1. Validating semantic predicate, to place constraints on rules. For example
data : ( b += BYTE )+ {$b.size() <= 4}? ;
2. Gated semantic predicate, to turn on some alternatives under runtime condition. For example:
stat: ifState | {allowAssert}?=> assertStat ;
3. Disambiguating semantic predicate, to choose alternatives based on semantic context. For example:
stat: keyIf ID stat | keyCall ID ‘;’ ;
keyIf: {input.LT(1).getText().equals(”if”)}? ID ;
keyCall: {input.LT(1).getText().equals(”call”)}? ID ;

How to read cassandra source code by Ran

frank — Mon, 03 May 2010 15:34:32 +0000

Here is a good article explaining how to read cassandra source codes:

Understanding Cassandra Code Base
http://prettyprint.me/2010/05/02/understanding-cassandra-code-base/

A simple thrift tutorial

frank — Wed, 07 Apr 2010 21:23:43 +0000

Check it out at http://skorage.org/2009/03/08/simple-thrift-tutorial/

Let firefox use your Windows authentications automatically

frank — Tue, 06 Apr 2010 21:11:19 +0000

In Firefox, visit:

about:config

Then set network.automatic-ntlm-auth.trusted-uris to your trusted domains, separated by comma.

A very nice presentation about agile software development

frank — Fri, 02 Apr 2010 14:44:03 +0000

Some of my thoughts: Unit tests are very important in TDD. It enables you easily refactor code, adhere to customer requirements, and verify logics at earliest points. It also enables Continuously Integration to work brilliantly.

Lions, Tigers, and Bears: Scrum, XP, and Eclipse

View more presentations from kingargyle.

Interesting lessons in Cassandra Slides

frank — Tue, 02 Mar 2010 19:49:38 +0000

There is a famous Cassandra PPT at SigMod 2008. In one slide, they presented several interesting lessons:

Add fancy features only when absolutely required
Many types of failures are possible
Big systems need proper system-level monitoring
Value simple designs

These lessons are interestingly useful.

The Visualization of Browser War

frank — Sat, 06 Feb 2010 05:04:13 +0000

This is pretty interesting:

The Visualization of Browser War

Create a commercial-quality Eclipse IDE by IBM

frank — Sat, 06 Feb 2010 00:14:32 +0000

This should be a good tutorial. I need to look into it:

http://www.ibm.com/developerworks/edu/os-dw-os-ecl-commplgin1.html

I know there is an excellent tutorial in Chinese. It demos how to craft a source code editor using Eclipse JFace Text Framework and a bit ANTLR. The link is here.

ANTLR v3 Tutorials Aggregation

frank — Sat, 06 Feb 2010 00:01:20 +0000

Here are some tutorial links for learning antlr v3:

The Getting Started Tutorial from Official Site is Damn Good!
ANTLR Works is a damn good tool!
The Definitive Antlr Reference is a good book
ANTLR 3.X Tutorials are good video course and introduced a damn good eclipse tool: ANTLR IDE.

Mouse-click on Buttons Doesn’t Work in Ubuntu 9.10?

frank — Wed, 03 Feb 2010 20:25:06 +0000

After installing Ubuntu 9.10, eclipse became naughty. I tried to create a Java Project. However, mouse-click on Next/Finish buttons didn’t work. The buttons got focused, but no response. So you have to press ENTER or SPACE to actually press the buttons.

A quick fix here: create a shell script. For example, eclipse.sh:

export GDK_NATIVE_WINDOWS=1
/home/frankdu/Developer/eclipse/eclipse

Then add executable permission to the file: chmod +x ./eclipse.sh

Every time you run eclipse.sh to launch eclipse. At least we can be happy for a while. Please see http://www.eclipse.org/forums/index.php?t=msg&goto=498640& for more information.