Build: `jpm test` runs all tests; `janet test/<file>.janet` runs single. Source in `src/jolt/`, tests in `test/`. Entry: `src/jolt/main.janet`. Key files: compiler.janet (848L, 2-phase analyze→emit), evaluator.janet (interpreter with 21 special forms), core.janet (~130 Clojure core fns), types.janet (Var/Namespace/Context), reader.janet (parser), phm.janet (PersistentHashMap + LazySeq + PersistentHashSet), api.janet (public API + compile? dispatch), loader.janet (file loading).
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Architecture: Two eval modes — compile (`:compile? true`) uses analyze-form→emit-expr→Janet eval; interpreter mode uses tree-walking evaluator.janet. Stateful forms (defmacro, ns, deftype, defmulti, defmethod, syntax-quote, set!, var, ., new) always fall back to interpreter. Macros expand at analyze time. Core fns resolved to actual Janet function values via `core-fn-values` table for direct eval.
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Compile-mode eval path: `compile-and-eval` → `compile-ast` (emits Janet data structures with resolved fn values) → Janet `eval`. Source-to-source `compile-form` exists for debugging but NOT used by compile-and-eval. `compile-and-eval` interns def/defn results in Jolt namespace so interpreter can resolve them later.
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REPL: `main.janet` initializes context and sets current ns to "user". `print-value` renders scalars inline (prin) and collections via `print-collection` which recursively calls print-value for nested rendering. Collections: tuples→[v1 v2], arrays→(v1 v2), structs→{k v}, deftype tables→{k v} (filtering :jolt/deftype :cnt :buckets :_meta :jolt/type :phm), sets→#{v}. Jolt symbol structs render as `name` or `ns/name`.