Janet `and` returns last truthy value, not boolean. `(and table? deftype)` returns the deftype string, not true. Predicate-like functions (core-map?, core-contains?, etc.) that check type tags via `(and ...)` must wrap in `(if ... true false)`. Hit us with core-map? returning the deftype string instead of boolean true for record instances. Also hit type-satisfies? which had to replace `(boolean ...)` (nonexistent) with `(if ... true false)`.
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Clojure .clj source files loaded via eval-form cannot have docstrings. If a defn form has 5 elements (defn, name, docstring, params, body), the evaluator's defn macro handler gets 4 args instead of 3, breaking with "macro arity mismatch". All .clj files in src/jolt/clojure/ must use 4-element defn forms: (defn name [params] body). Docstrings on defn are a Clojure feature not supported by Jolt's defn macro.