The parser's token union. What a front-end hands over before any statement names the expected type. Consumed once, during resolution — never stored past it. Three cases, by design: a number token, a decimal token, and a word (a bare identifier, a quoted string, or `true`/`false`). There is no arithmetic case (the resolver computes; the text never does) and no parameter case (sizes come from properties). Not a struct union by language rule: a multi-case struct union needs one shared field type, and `Word` carries a string. Args live only at parse and resolve time (never per frame), so the allocations do not reach a hot path.