Comment nodes and keywords in Nashorn AST

A DESCRIPTION OF THE REQUEST :
Script comments currently get swallowed by the parser and only the relevant code is visible in the tree.

Same for keywords in structures like
  do {
     stmt;
  } while (true);
The AST nodes only show the position of the entire do-while-loop, the stmt and the condition, not the "do" or the "while" keywords. (Ok, "do" is always at the start, but "while" is a problem when there is whitespace.)



JUSTIFICATION :
In order to do proper syntax highlighting on JavaScript, you need to know the location of comments (line and block) and keywords in a script.

Mozilla Rhino has special flags to activate comment output in ASTs.
        env.setRecordingComments(true);
        env.setRecordingLocalJsDocComments(true);
And it had methods like
        DoLoop.getWhilePosition()

I can't replace the old Rhino code until this information is present.