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Get it at http://www.antlr.org/download.html. Shooting for a much quicker b3 then full 3.1 (early August?). Release notes.
Last changed Jul 17, 2008 11:19 by Terence Parr
JDK javac compiler ANTLR grammar. The OpenJDK community has announced the approval of a new project, Compiler Grammar. The Compiler Grammar project's goal is "to develop an experimental version of the javac compiler based upon a grammar written in ANTLR."
Spent hours and hours on airplanes recently bouncing around Europe giving talks. had some time to think about increasing the recognition strength of LL by increasing the prediction mechanism from a DFA to a pushed down machine, either LL or LR. I've scanned my notes and diagrams; see the attachments on this news item. I tried all sorts of things trying to approximate non-regular lookahead languages but didn't really come up with anything great. One thing of note,...
Last changed Jun 26, 2008 09:08 by Terence Parr
Back from my trip to Europe (including Ireland). Found the ANTLR pub in a small town as I was driving around western Ireland outside of Galway. They didn't spell it properly, but perhaps Antler is the Gaelic spelling of ANTLR.
Last changed Jun 11, 2008 01:34 by Terence Parr
As Java gets more and more complicated with generics, closures, etc... I keep looking for simplicity. I have the Mantra prototype, but even that subset is kind of complicated. I decided to look at Smalltalk again. Coincidentally, Nik Boyd, who built Bistro years ago contacted me; he's moved to SF Bay area, which means we can chat in person....
Last changed Jun 06, 2008 13:35 by Terence Parr
The Default error handling mechanisms that does single token insertion and deletion works really well in many cases. The one area where I think ANTLR need some work is during no viable alternative exceptions and loops around rule references. For example, what happens if you have a fragment like:
d : decl+ ;
decl: 'foo'
| 'bar'
;
If you have input ")) foo bar foo", which is valid except for the crazy "))" at the front,...
ANTLR 3.1b1 is now available for testing. 3.1 should appear by early June 2008; has C, C#, Java, Python, and ActionScript targets.
Last changed May 09, 2008 16:50 by Terence Parr
Currently syntax errors cause invalid trees and possibly even runtime exceptions when building ASTs. What we really need I believe is to have rules that encounter syntax errors return an ERROR node of some sort that records where the error occurred and, with luck, the tokens consumed during recovery. I started an improvement request:
http://www.antlr.org:8888/browse/ANTLR-193
The basic idea is that ERROR nodes get used in place of ASTs that would normally be produced by rule indications....
Last changed May 03, 2008 10:43 by Terence Parr
just had some cool ideas about a semantic rule specification language...i should write that up too... (also think about multi-threaded rewriting; no side-effects required
Some language translation problems can be described with a few rewrite rules that are predicated upon their context and potentially an arbitrary Boolean expression. For example, consider a few identity transformations such as
expr: // in context of expr, match left side,...
Last changed Apr 11, 2008 11:37 by Terence Parr
Currently ANTLR does not create templates for you automatically when you use output=template option. This is because, when I first implemented it, I had no idea what the right answer was here. I did not know how to deal with whitespace and so on. I think I have the answer now. First, let me remind you that output=AST builds a completely flat tree given no instructions to the contrary. Similarly, the template output should reproduce the input given no instructions.
...
Last changed Jun 19, 2008 07:09 by Terence Parr
Ok, Kay Roepke is in town and we've been discussing the faster expression parsing, among other things. Look for another entry on default StringTemplate generation or a parsing and tree parsing.
Found a ref to Keith Clarke's original recursive-descent precedence work
ANTLR v3.2 will allow special rules for specifying expressions that are particularly efficient both in speed and space....
Last changed Apr 08, 2008 15:23 by Terence Parr
I should be working on something else but got to thinking about how annoying it is specifying expressions in recursive descent parsers. You have to have a new rule for each precedence level. This is also very slow. Just to match 34 it has to descend about 15 method calls. I built a prototype single-rule (plus primary and suffix) operator matching thingie which I enclose below. I should be able to generate it from some metameta syntax in antlr. For example,...
I'll be giving a keynote lecture at this year's conference on program comprehension in Amsterdam if anybody's interested in going:
http://www.cs.vu.nl/icpc2008/keynote.php
I think I will also be giving a talk at CWI. June 10-13.
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