5.3.0: Yield all tokens as written

• Fixed named arguments using keywords - @thekid
• Changed tokens to yield variables including the leading $ sign
  (@thekid)
• Fixed visitor API for unary prefix (e.g. ++$i) and unary suffix
  (e.g. $i++) operators
  (@thekid)

5.2.0: Named arguments

• Merged PR #13: Add syntactic support for named arguments (PHP 8), see
  https://wiki.php.net/rfc/named_params
  (@thekid)

5.1.0: Comments

• Merged PR #12: Improve tokenizer performance - @thekid
• Merged PR #11: Yield comments from tokenizer - @thekid
• Merged PR #10: Fix PHP 8 native syntax - @thekid

5.0.0: Integrate parser

• Merged PR #8: Add support for match expression - @thekid
• Added builtin support for null-safe instance operator ?->, see
  https://wiki.php.net/rfc/nullsafe_operator & xp-framework/compiler#9
  (@thekid)
• Merged PR #7: PHP8 attributes support - @thekid
• Integrated throw expressions, see xp-framework/compiler#85 - @thekid
• Fixed missing support for insteadof trait keyword - @thekid
• Merged PR #1: Integrate parser
  • Migrate tokenizer, parser and language from xp-framework/compiler
  • Added enclosing type to constants, properties and methods
  • Added lang.ast.Node::is() method to check for node kind
  • Added lang.ast.nodes.TypeDeclaration::declare() in favor of inject.
  • Added new parse tree API
  • Added new visitor API
  • Refactored types API to dedicated package lang.ast.types
  • Added dedicated classes for nullable, literal and value types
    (@thekid)

4.0.0: Drop PHP5

• Dropped support for PHP 5.6, see xp-framework/rfc#334 - @thekid

3.0.3: XP10 compatibility

• Added compatibility with XP 10, see xp-framework/rfc#333 - @thekid

Return statement fix

• Fixed issue #5: Call to a member function children() on null - @thekid

3.0.1: Children iteration fix

• Fixed xp-framework/compiler#71: Call to a member function children()
  on array, which occured with if, catch and switch statements
  as well as for array literals.
  (@thekid)

3.0.0: Element -> Node, Code generator

• Heads up: Changed transformation API - functions must accept a
  reference to the code generation process as their first parameter.
  (@thekid)
• Heads up: Added kind to UnaryExpression constructor which is
  either prefix or suffix, supporting ++$i as well as $i++.
  (@thekid)
• Merged PR #4: Add Node class replacing Element and Value - @thekid

2.0.0: Compact AST

• Merged PR #3: Allow multiple transformations per kind - @thekid
• Heads up: Removed Symbol and Node classes, which belong to the
  compiler internals now only
  (@thekid)
• Merged PR #2: Refactor AST. This makes programmatic AST creation far
  easier and improves on memory usage.
  (@thekid)