[news.eclipse.technology.dltk] Re: Tips about building AST

[Kevin KIN-FOO <kkinfoo@xxxxxxxxxxxxxxxx>]

Hi Alex,

Your answer is very quick and helpful. I'm still working on AST
generation and I'm wondering if it's possible to use an AST from another
language as reference.

I mean, I have an AST representing the code in another language that is
gifted for AST manipulation, can I do  a proxy through it with a
ModuleDeclaration Object ? Is it a good idea ? Did anyone tried it before?

Regards

Alex Panchenko a écrit :
> Hi Kevin,
> 
> ModuleDeclaration is just a class to return AST of the source module, so
> it should be only one instance at the top of tree.
> 
> The natural way to navigate over AST is traverse() method, getChild() is
> just a helper method and ASTNode's implementation uses traverse() to
> collect it's direct children.
> 
> So, your classes should look like:
> 
> public class RubyIfStatement extends ASTNode {
>     private ASTNode fCondition;
>     private ASTNode fThenStatement;
>     private ASTNode fElseStatement;
> 
>     public RubyIfStatement(ASTNode condition, ASTNode thenStatement,
> ASTNode elseStatement) {
>         this.fCondition = condition;
>         this.fThenStatement = thenStatement;
>         this.fElseStatement = elseStatement;
>     }
> 
>     public void traverse(ASTVisitor pVisitor) throws Exception {
>         if (pVisitor.visit(this)) {
>             if (fCondition != null) {
>                 fCondition.traverse(pVisitor);
>             }
>             if (fThenStatement != null) {
>                 fThenStatement.traverse(pVisitor);
>             }
>             if (fElseStatement != null) {
>                 fElseStatement.traverse(pVisitor);
>             }
>             pVisitor.endvisit(this);
>         }
>     }
> ....
> }
> 
> Regards,
> Alex
> 
> Kevin KIN-FOO wrote:
>> Hi,
>>
>> I'm trying to build a DLTK compliant AST and I'm facing an issue
>> building the parser. I've noticed that there is a "getChilds()" method
>> on every ASTNode, but you cant add any child node. Reading the code of
>> the Python IDE example, I discovered that ModuleDeclaration objects
>> accept child nodes with the "addStatement()" method. So, there is My
>> question.
>>
>> Is it possible to have several ModuleDeclaration objects in one single
>> AST? If no, what is the proper way to link ASTNode objects together ?
>>
>> Regards
>