XPath and Piggy

I’ve made another release of Antlrvsix, version 7.3, last week and I’m almost ready to release 7.4 with a few more fixes. The changes I’ve been making since last year in August have greatly enhanced what Antlrvsix can do over version 1. But, there is more work to be done. I’m now working on updating and integrating Piggy into the extension.

Part of the problem with Piggy was that I lacked a clear vision of what I was trying to solve. I now know what I’m looking to solve because I have worked on the analysis and transformations for Antlr. And, I can see there are actually two levels to this system: (a) a high-level language, that works with snippets in the language that is going to be modified, and (b) a low-level language, that works with tree patterns and routines to manipulate those trees. This was what the authors of Coccinelle did, and it is the right idea because it’s hard writing tree patterns in a language like XPath, which is just a language that specifies a collection of tree nodes.

I will first start writing an interface for XPath because all the transforms use a basic tree node find and replace. I will first try porting Eclipse XPath written in Java to C# and see where that takes me. The port will be here.


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