Weiqi Gao's Observations - antlr tag

Java News Brief (JNB): ANTLR 3.0

Wed, 04 Jun 2008 15:33:29 GMT

This month's OCI Java News Brief (JNB) article is out. In this article, Mark Volkmann continues his effort in getting you to be proficient with ANTLR 3.0. (Actually, you need ANTLR 3.1b1 to compile the grammars in the article.)

Mark Volkmann:
ANTLR 3.0

by
R. Mark Volkmann, Partner/Software Engineer
Object Computing, Inc. (OCI)

Table of Contents

Part I - Overview

Introduction To ANTLR

ANTLR Overview

Use Cases

Other DSL Approaches

Definitions

General Steps

Part II - Jumping In

Example Description

Important Classes

Grammar Syntax

Grammar Options

Grammar Actions

Part III - Lexers

Lexer Rules

Whitespace and Comments

Our Lexer Grammar

Part IV - Parsers

Token Specifications

Rule Syntax

Creating ASTs

Rule Arguments and Return Values

Our Parser Grammar

Part V - Tree Parsers

Rule Actions

Attribute Scopes

Our Tree Grammar

Part VI - ANTLRWorks

Part VII - Putting It All Together

Using Generated Classes

Ant Tips

Part VIII - Wrap Up

Hidden Tokens

Advanced Topics

Projects Using ANLTR

Books

Summary

References

As always with JNB articles, this one is intended for you to follow along. So download ANTLR 3.1b1, fire up your bash and vim, and learn some language recognition tricks.

On a related note, Martin Fowler recently blogged about a phenomenon he calls Parser Fear:

Martin Fowler: I talk quite a bit with people about DomainSpecificLanguages these days and a common reaction I get to external DSLs is that it's hard to write a parser.

He went on to say that creating an external DSL with ANTLR is just as fast as using XML files, where supposedly you get the parser for free.

Mark Volkmann: An Introduction To ANTLR v3

Tue, 19 Feb 2008 02:43:09 GMT

Last Friday, Mark Volkmann presented a tutorial on ANTLR v3 at the OCI internal Java lunch. Since Mark has posted his presentation slides out on the internet, I did not take my usual amount of notes.

For me, ANTLR has been something that I'm aware of for a long time. I may have encountered it before it became ANTLR (PCCTS) when it was C++ based. However, its lack of applicability in everyday programming and the terseness of the documentation meant that I never get to know it well enough to actually use it in production code. The situation changed last year when the Pragmatic Bookshelf published the The Definitive ANTLR Reference book.

I have been staring at my copy of the book for a few months waiting for the time when I would have a big chunk of time to start reading and experimenting with it. Mark's talk gave me enough of a push to start my experimentation with ANTLR v3. Hopefully, this time I can sustain my energy and finish the book.

And one particularly good thing about Mark's talk is that its accompanied by a couple of examples that I can play with. Here's what the example does:

[weiqi@gao Math]$ java -jar build/math.jar 
math> f(x) = x^2 - 3x + 2
math> print f()
f(x) = x^2 - 3x + 2
math> print f'()
f'(x) = 2x - 3
math> print f(3)
2.0
math> help
In the help below
* fn stands for function name
* n stands for a number
* v stands for variable

To define
* a variable: v = n
* a function from a polynomial: fn(v) = polynomial-terms
  (for example, f(x) = 3x^2 - 4x + 1)
* a function from adding or subtracting two others: fn3 = fn1 +|-ghg fn2
  (for example, h = f + g)

To print
* a literal string: print "text"
* a number: print n
* the evaluation of a function: print fn(n | v)
* the defintion of a function: print fn()
* the derivative of a function: print fn'()
* multiple items on the same line: print i1 i2 ... in

To list
* variables defined: list variables
* functions defined: list functions

To get help: help or ?

To exit: exit or quit

If you've been trying to get to know a little bit about ANTLR but never have the right incentive or courage to open the book, give Mark's presentation material a try. And if you are in the St. Louis area, Mark will be giving the same presentation at the NFJS conference in March and the St. Louis Java Users Group in June.

Come!

ANTLR 3.0 Is Released

Fri, 18 May 2007 02:45:42 GMT