- // The current (innermost) frame. `frame` and `stack` could be combined,
- // but it's faster to have them separately to access `frame` directly
- // rather than via something like `stack.last().unwrap()` or
- // `stack[stack.len() - 1]`.
- frame: TokenCursorFrame,
- // Additional frames that enclose `frame`.
- stack: Vec<TokenCursorFrame>,
+ // Cursor for the current (innermost) token stream. The delimiters for this
+ // token stream are found in `self.stack.last()`; when that is `None` then
+ // we are in the outermost token stream which never has delimiters.
+ tree_cursor: TokenTreeCursor,
+
+ // Token streams surrounding the current one. The delimiters for stack[n]'s
+ // tokens are in `stack[n-1]`. `stack[0]` (when present) has no delimiters
+ // because it's the outermost token stream which never has delimiters.
+ stack: Vec<(TokenTreeCursor, Delimiter, DelimSpan)>,
+