question: private CustomInternalN4JSParser collectFollowElements ( TokenSource tokens , boolean strict , Set < FollowElement > result ) { CustomInternalN4JSParser parser = createParser ( ) ; parser . setStrict ( strict ) ; try { ObservableXtextTokenStream tokenStream = new ObservableXtextTokenStream ( tokens , parser ) ; result . addAll ( doGetFollowElements ( parser , tokenStream ) ) ; } catch ( InfiniteRecursion infinite ) { result . addAll ( parser . getFollowElements ( ) ) ; } return parser ; }
target:  First pass. Use the tokens that have been computed from the production parser's result and collect the follow elements from those.