whole-function comptime folding for zero-runtime value calls

std/meta/meta.hon

@@ -0,0 +1,61 @@
+Layout :: enum { auto, c }
+
+ArrayInfo :: struct {
+	child type
+	len usize
+}
+
+FieldInfo :: struct {
+	name []u8
+	type type
+	index usize
+}
+
+RecordInfo :: struct {
+	name ?[]u8
+	fields []FieldInfo
+	is_tuple bool
+	layout Layout
+}
+
+EnumInfo :: struct {
+	fields []FieldInfo
+}
+
+TypeInfo :: union(enum) {
+	invalid void
+	void void
+	noreturn void
+	anyopaque void
+	bool void
+	integer void
+	float void
+	array ArrayInfo
+	pointer void
+	slice void
+	range void
+	optional void
+	function void
+	enum EnumInfo
+	record RecordInfo
+	union void
+	fallible void
+	distinct void
+}
+
+EnumFieldStruct func($E, $Field type, $default ?Field) type {
+	match typeinfo!(E) {
+		.enum |info|: {
+    		names [info.fields.len]mut []u8 = undefined
+    		field_types [info.fields.len]mut type = undefined
+    		defaults [info.fields.len]mut ?Field = undefined
+			expand for info.fields |field, index| {
+				names[index] = field.name
+				field_types[index] = Field
+				defaults[index] = default
+			}
+			return struct_type!(.auto, names, field_types, defaults)
+		}
+		else: compile_error!("EnumFieldStruct key must be an enum")
+	}
+}