The `unless` macro's expansion was updated to use `...` (NOP) instead of
`void`. This change also involved removing the `void` keyword from the
parser, as it is no longer used.
This commit introduces support for AST macros and templates, enabling
users to define and use custom, reusable components within the visual
DSL.
Key changes include:
- A new `MacroRegistry` to manage macro definitions.
- A `MacroExpander` to process macro calls and expand templates.
- A `MacroEvaluator` trait for evaluating expressions during expansion.
- The `Expansion` node in `BoundKind` to preserve the original macro
call and its expanded form for debugging.
- Updates to the `Binder`, `Dumper`, and `UpvalueAnalyzer` to handle the
new macro constructs.
- New examples demonstrating various macro functionalities like
`unless`, splicing, and nested macros.
Michael Schimmel