[antlr-interest] [newbie] AST Rewriting

[Robin]

Hey !

Also note that ANTLR 4.x will no longer be supporting tree rewrites in the
> grammar; currently ANTLR 3.x be will the last version to support them.
>

I wasn't aware of that and it changes a lot of stuff about the project
behind all this :)


Since you already know how to get the AST, all you have to do now is treat
> the AST as any n-ary tree and manipulate.
>
> Instead of jumping right into your problem, take some time to write a tree
> walker, a print routine, and some search routines, i.e. find text, find
> node type, return a node, return a branch with children, etc.. You will
> need to write them because they will help you understand trees and for
> debugging.
>
> Next you will need to understand the basic methods in the tree API,
> basically the BaseTree, and CommonTree classes.
> If you take a look at the previous post "Help with compressin​g trees and
> custom nodes" you will find some C# examples I give for using them.
>

Thanks for the advice. It looks like I have some homework :P


I'll try to write a simple tree walker that only prints stuff and once I
get comfortable with this, I'll see if I have more questions :>

--robin


On Mon, Mar 19, 2012 at 7:04 AM, Robin <diabeteman at gmail.com> wrote:
>
>> Hello list :)
>>
>> I am trying to rewrite an AST (by filtering out most of the nodes). From
>> what i could read on antlr wiki and some interesting forums & other
>> medias,
>> you can do this with tree grammars and tree operators "->".
>>
>> The grammar I use to generate AST is here
>> http://www.antlr.org/grammar/1207932239307/Java1_5Grammars and here is my
>> test rig http://pastebin.com/LeR4miVu
>>
>> I modified JavaTreeParser.g and added the options output = AST; and
>> rewrite
>> = true; Also, just for testing purposes, I added "->" at the end of each
>> rule in order to filter out all of the nodes. Here is what it looks like
>> http://pastebin.com/u6UG7fEB
>>
>> The problem is that in my test rig, the returned tree is not rewrited at
>> all.
>>
>> I am sure I'm doing something wrong. Could you help ?
>>
>> Thanks in advance,
>> Robin
>>
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