[antlr-interest] Re: AST algorithm stuck in infinite loop?

[jw9315]

Apologies, the algorithm was not stuck in a loop, it was just taking 
so long to complete that I did not notice! It still seems to go 
through the same branch many times though, I was wondering if it was 
meant to do this, or it was an error in the implementation of the 
algorithm?
Thanks,
Jon

--- In antlr-interest at yahoogroups.com, "jw9315" <jw9315 at b...> wrote:
> Hi,
> I implemented the following algorithm to walk an AST as suggested 
by 
> a member of this group:
> 
> // Start
> void visit( AST tree )
>  {
>          AST child = tree.getFirstChild();
>          System.out.println("_" + child);
>          // Test to see if node has a child
>          if( child != null) 
> 	 {
> 		 System.out.println(child);
>                  // Call method recursively
> 		 visit( child ); 
> 	 }
>          // Else there were no children
>          AST sibling = tree.getNextSibling();
>          while( sibling != null)
> 	 {
> 	 	System.out.println(sibling);
> 		visit( sibling );
> 		sibling = sibling .getNextSibling();
>  }
> // End
> 
> However, I find that this enters an infinite loop and prints the 
tree 
> out over and over again. Have I implemented the algorithm 
correctly, 
> and if so, could someone tell me how to test for the fact that I 
have 
> walked the whole tree? Is there a special command for this?
> Thanks in advance,
> Jon


 

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