[antlr-interest] How can I modify a tree node value according to the value of another tree node ?

[Michael Bedward]

> How could I store value in AS.g and how can AS.g and AStree.g communicate?
> Could you plz give me a small example?
>

Hi Annie

Just define variables in the members section of each grammar.

Here's a general example where parser grammar A.g needs to collect
data which will then be used in tree grammar Bwalker.g

In grammar A.g...

@members {
private List<MyClass> myList = new ArrayList<MyClass>();

public List<MyClass> getList() { return myList; }
}

Then one or more rules in A.g have actions to create MyClass objects
and add them to the list.

In grammar Bwalker.g...

@members {
private List<MyClass> aList;

public void setList( List<MyClass> list ) { aList = list };
}

Now the client code runs AParser and gets the AST and the list...

AParser parser = new AParser(...);
AParser.prog_return r = parser.prog();
CommonTree primaryAST = (CommonTree) r.getTree();
List<MyClass> listFromA = parser.getList();

Then it gives the AST and the list to Bwalker...

CommonTreeNodeStream nodes = new CommonTreeNodeStream(primaryAST);
nodes.setTokenStream(tokens);
BWalker bwalker = new BWalker(nodes);
bwalker.setList( listFromA );
BWalker.start_return r = bwalker.start();

Hope this helps
Michael