This commit introduces fundamental changes to Myc's language structure
to enhance type safety and scoping clarity.
Key changes include:
- Introducing local scopes for `do` blocks.
- Separating statements (`def`, `assign`) from expressions, where
statements now have no return value and are only allowed within
blocks.
- A block now consists of multiple statements followed by a single final
expression.
- Stricter validation rules are enforced, such as disallowing
redefinition of local symbols in the same scope while allowing
shadowing of outer symbols.
- Compiler errors are generated for statements used in expression
contexts.
The implementation involved modifications to the AST, parser, binder
(scope-stack), and various compiler passes, along with VM runtime
optimizations.
Michael Schimmel