hakorune/docs/guides/template-unification.md

Template → Macro Unification (Breaking Change)

Status: Active. Templates are now specified and executed via the Macro Engine. There is no separate “template pipeline”. This simplifies expansion order, diagnostics and tooling. The --expand flow shows both macro and template (pattern/unquote) transformations.

What changed

• Template constructs are expressed using the macro Pattern/Quote API.
• $name and $...name (variadic) placeholders are part of macro templates.
• Arrays/Maps are supported in both matching and unquote.
• There is no legacy, template-only expansion pass.

Authoring

• Programmatic API (Rust): crate::macro::pattern::{TemplatePattern, OrPattern, AstBuilder}.
• Textual quote is a convenience helper: AstBuilder::quote("code here") and unquote with variable bindings.
• Variadics:
  • $...tail can appear at any position in call/array arguments.
  • During match: the variable-length segment is bound to an ASTNode::Program.
  • During unquote: the Program’s statements are spliced into the argument list.

Tooling

• nyash --expand --dump-ast file.nyash shows pre/post expansion.
• Macro gate: NYASH_MACRO_ENABLE=1.

Compatibility

• This is a breaking change. Existing “template-only” extension points must adopt the macro engine.
• Guidance: treat templates as macro sugar; move any custom template processors to macro patterns.