# KDL Changelog

## 2.0.0 (2022-08-28)

### Grammar

* Solidus/Forward slash (`/`) is no longer an escaped character.
* Single line comments (`//`) can now be immediately followed by a newline.
* All literal whitespace following a `\` in a string is now discarded.
* Vertical tabs (`U+000B`) are now considered to be whitespace.
* Identifiers can't start with `r#`, so they're easy to distinguish from raw
  strings. (They already similarly can't start with a digit, or a sign+digit,
  so they're easy to distinguish from numbers.)
* The grammar syntax itself has been described, and some confusing definitions
  in the grammar have been fixed accordingly (mostly related to escaped
  characters).
* `,`, `<`, and `>` are not legal identifier characters. They were previously
  reserved for KQL but this is no longer necessary.

### KQL

* There's now a _required_ descendant selector (`>>`), instead of using plain
  spaces for that purpose.
* The "any sibling" selector is now `++` instead of `~`, for consistency with
  the new descendant selector.
* Map operators have been removed entirely.