[antlr-interest] How to get GUI like tree structure

[Jim Idle]

I think you are looking for the wrong thing. You are unlikely to need the parse tree in order to operate upon the input. You are almost certainly in need of an AST that you build yourself using the ANTLR tree building constructs.

 

Did you search the WIKI:

 

http://www.antlr.org/wiki/pages/viewpage.action?pageId=1760

 

Jim

 

 

From: Ketan Maheshwari [mailto:ketancmaheshwari at gmail.com] 
Sent: Wednesday, March 31, 2010 7:47 AM
To: Jim Idle
Cc: antlr-interest at antlr.org
Subject: Re: [antlr-interest] How to get GUI like tree structure

 

Hi Jim, Hi All

 

I searched but still am struggling to really get the parsertree object for my grammar. 

 

My goal is to get the parser tree object just as being shown in the GUI and put its elements in another object that I need to construct based upon the tree.

 

But after a lot of search I still have no clue how do I get the ParserTree object with a *hierarchy of rules* and leaf nodes as the actual *tokens* of my program!

 

Many thanks for any help with this.

 

Regards

Ketan

 

On Mon, Mar 29, 2010 at 6:30 PM, Jim Idle <jimi at temporal-wave.com> wrote:

Ah. You are asking for the parser tree, not a representation of the AST? Search the mailing list for this. Such a tree is not generally useful for doing things with (so if you are looking for this information because you want to use it to generate code or something, then you are probably looking at your problem incorrectly), but it is very useful for debugging the tree.



http://antlr.markmail.org/search/?q=parse+tree





If all you want is information in the nodes, then get the payload of the leaf node (usually CommonToken) and ask for it, but that’s what the code you looked at is doing.



Jim





From: Ketan Maheshwari [mailto:ketancmaheshwari at gmail.com]
Sent: Monday, March 29, 2010 9:18 AM
To: Jim Idle
Cc: antlr-interest at antlr.org
Subject: Re: [antlr-interest] How to get GUI like tree structure




Jim



Thanks again for your answer.



1. I checked the DOTTreeGenerator.java code but I do not seem to know how it finds all the info about a tree. Also I am confused with its use of both the stringtemplates and trees (are'nt they mutually exclusive?).



2. Yes, the toStringTree() method prints the tree but it only gives the leaf nodes, that is the program itself. I have no info about which rule a given token belongs to.



To be more clear, see the attached snapshot. My question is how can I capture this parse tree in a some kind of java data structure and walk through it.



Many Thanks again for all your help.

Ketan



On Mon, Mar 29, 2010 at 5:41 PM, Jim Idle <jimi at temporal-wave.com> wrote:

Look at the code for DOTTreeGenerator.java or use toStringTree() if that gives you a good enough representation.

Jim


> -----Original Message-----
> From: antlr-interest-bounces at antlr.org [mailto:antlr-interest-
> bounces at antlr.org] On Behalf Of Ketan Maheshwari
> Sent: Monday, March 29, 2010 7:36 AM
> To: antlr-interest at antlr.org
> Subject: [antlr-interest] How to get GUI like tree structure
>
> Hello Friends
>
> I am trying to use the CommonTree generated by the parser of my grammar
> against a test code.
>
> Using the getChild(index).toString method, I get the tokens well.
>
> However, I do not know how can I also get a hierarchy of the rule to
> which
> they belong to. Similar to what we get in the ANTLRworks GUI.
>
> Any clue how can I get a tree such that it shows complete hierarchy of
> the
> grammar and the tokens as leaf nodes only.
>
> Am I using the correct Data Structure (CommonTree) ?
>
> Thanks for any clues.
>
> Regards
> Ketan
>

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