Objective-C target

Author

Alan Condit

acondit(at)alansmachineworks(dot)com

Derived from work by:
Image Added

Kay Röpke
kroepke(at)classdump(dot)org

Status

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The next current ANTLR beta release will include includes a working Xcode plugin, so you can automatically generate your grammars from within Xcode.
It automatically tracks all the dependencies between the different grammars in your project to build them in the right order.
Common error messages and warnings are picked up for display in Xcode using the new -message-format gnu option in ANTLR.
There remain some errors and warnings which cannot be picked up yet, due to missing information in ANTLR itself, but this will may change in the future.
Debugging support for use with ANTLRWorks is done, except for exceptions I just haven't got around to do it yet. The socket handling code isn't error proof yet, I will add more thorough error handling for the final version. Other than that it works beautifully!

ANTLR.framework

Features (partially) missing are:

• Scopes
  • multiple return values need testing/enhancements
• Labels
  • other labels
• Tests - well, most of them
• Template support (this will be a lot of work Template support (postponed because there is no ST grammar for ANTLR v3 yet)
• Debugging support for exceptions (Objective-C exceptions must match the exact names of the Java exception classes)

Features completed:

• Single rule return values
• FOLLOW sets (bitsets)
• cyclic DFAs
• Scopes (assignment to scope attributes need some fixes in ANTLR to work, I have those locally but they are not integrated yet)
  • dynamic scopes
  • rule parameters
• Labelstoken reference labels
• Syntactic Predicates
• Semantic predicates
• Tree support (buildASToutput=trueAST)
• Tree parsers
• Debugging support for parsers.
• Debugging support for AST building.

ANTLR Xcode plugin (Kay's work. I have done nothing with this other than use it.)

Features missing:

• Syntax highlighting & function popup support (I'd still encourage you to use ANTLRWorks for development!) For this I need more understanding of the dreaded classes Xcode uses internally, to be able to replace them with ANTLR3
• Debugging (long term goal)

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• Build settings you can pass to org.anltr.Tool
• Dependency calculation
• Code generation
• Most common All warnings & error messages are sent to Xcode, syntax errors in the grammar aren't correctly reported yetpicked up by Xcode.
• Basic syntax highlighting works, using the standard Xcode mechanisms

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Building ASTs and tree parsers is working now. ANTLR.framework is known built to be Universal, but only tested on Intel machine.
I will use am using v3 to write a number of different small applications in order to find out about all the small bugs that are hiding in the corners. Thus development will probably not be milestone based, but rather fix-as-they-come-upsmall application. I will fix bugs as I become aware of them.
Regarding the template output support of v3, this will require an Objective-C implementation of ST , which will take a lot of time. So don't expect that for 3.0.
Soon I will add debugging support to the code generation and add a bit to ANTLRWorks to make it support debugging Objective-C based grammars in their natural environment (=your application) or as simple standalone recognizers.
There is a Xcode plugin available in the depot, which will be part of the next beta release. Contact me if you need binariesand I am not working on that, but help is always welcome.
I have ANTLRWorks generating code for Objective-C based grammars, but you will have to rebuild the ANTLRWorks jar to use it. You can also use the Xcode 2.4
plugin, available for download via link here . I have put up binary runtime framework on my page (see above).

Platforms

I will only concern myself with the Mac. There will be no GNUStep support.
As for Mac OS versions, I aim to be compatible with at least 10.3 6 as a target platform , though and the Xcode project will require the latest version availablewas built with 3.2.3, since it really doesn't make a lot of sense to use it in an earlier version.

The Xcode plugin requires at least Xcode 2.3 but should run with 2. 4, too.
Currently ANTLR requires 10.4. Unless   However, unless there are very good reasons to support versions prior to that10.6, it will not get priority. I don't have a machine on which to test earlier versions. Right now I am working on Snow Leopard (10.6). I expect the current version to "just work".

Runtime

The runtime will be is built in terms of the NS* level of classes, and is probably not very optimized in the first versions. I'll identify hotspots later and maybe add a CF-based runtime for speed if it turns out to be a problemlargely a fairly direct translation of the original java code.
The layout of the runtime is essentially the same as the Java version, though subtle differences will be visible where it makes it more natural to the Objective-C programmer. Naming of classes and methods may be slightly different and sometimes inner workings are too.
Initial tests don't show serious performance problems, though I'm sure there will be opportunities for optimization.
The biggest problem at the moment are the numerous unused variables created at the moment. Often ANTLR will build up lists of tokens but subsequently not use them in any significant way, which leads to wasting time and space. This can only be fixed in the ANTLR code generator and not for individual targets. I am looking into thisPart of the support for this is already there but it needs to be extended.

Examples

The goal is to provide the complete set of Java-based examples in Objective-C for comparison. There may be additional examples contained in the Xcode project. These exist mainly for development purposes as testcases, or to try out features.
I am currently working on an editor for StringTemplates as a big "example"/testcase for v3.
Also take a look at the Xcode plugin that uses a filtering lexer written using ANTLR to figure out grammar types and dependencies.