What reflection describes, and how a field carries metadata

Decided

D-0059, settled by the language’s author: part of spec §18. Older text cites it as 18.59.

Every kind of type, and an Odin-style tag per field. TypeInfo gains module_name, variants (an enum’s names and values; a union’s, with each payload’s fields), elem (a pointer’s, slice’s, array’s or optional’s element, an enum’s backing type), len, mutable and tag_offset; a str, a slice and an optional expose their parts as fields. FieldInfo has vis and owning instead of a flags set, and tag: a raw string ending the field declaration, name: String json:“player_name”``, read with tag_value(key). Chosen over struct-only tables, with which a serializer cannot write an enum by name or follow a slice, and over language-defined field attributes such as #[skip], which a JSON or save library could not extend: a tag is text only the library reading it gives meaning to. TypeId is a struct around the u32 rather than a bare u32, so an index is never mistaken for a number; the fields are type_id, module_name and owning because type begins a member (§8.5) and module and own are keywords. Names are Dazzle’s — List<i32> — with the module apart, replacing §13.5’s engine.Transform, which contradicted :: (§13)