New plans for macros

About to move them completely to stdlib

examples/hello-world/main.orc

@@ -1 +1,35 @@
 const main := println "Hello World!" exit_status::success
+
+macro (
+	rule match ...$expr { ...$body } => '(
+		fn::pass (...$expr) \match::value. ...$(
+			fn::pass (quote::split body ';) \cases.
+			fn::pass (list::map cases \x. (
+				fn::pass (quote::split_once x '=>) \pair.
+				tuple::destr pair 2 \req. \handler.
+				fn::pass (macro::run '(match::request (...$key))) \match_res.
+				quote::match '(match::response $decoder (...$bindings)) match_res \match_res_match.
+				fn::pass (option::expect match_res_match "Invalid pattern ${key}") \res_parts.
+				fn::pass (map::get_unwrap res_parts "decoder") \decoder.
+				fn::pass (map::get_unwrap res_parts "bindings") \bindings.
+				fn::pass (quote::to_list bindings) \binding_names.
+				fn::pass (list::rfold handler \tail. \name. '( \ $name . $tail )) \success.
+				'( $decoder $success )
+			)) \case_fns.
+			list::append case_fns '( panic "No cases match" )
+		)
+	)
+)
+
+--[
+	Conceptually, all matches are compared.
+		1. Within a macro, the top rule wins
+		2. If two winning matches are not within the same macro,
+			the one that matches the outermost, first token wins,
+			including tokens that are immediately captured, such that a rule starting with .. is
+			beaten by the same rule parenthesized and any rule starting with a scalar is beaten
+			by the same rule prefixed with a vectorial
+		3. If two winning matches start with the same token, an ambiguity error is raised
+
+	
+]--