Round 3 of the persistent-collections work. Lists were immutable Janet arrays,
so conj/cons-prepend was an O(n) copy (O(n^2) to build a list) — a large perf
gap vs Clojure's PersistentList.
Add src/jolt/plist.janet: an immutable cons-cell list (first/rest/count), same
algorithm as Clojure/CLJS/jank PersistentList. conj/cons onto a list now creates
an O(1) node that shares the existing list as its tail (no copy), with a cached
O(1) count. Repeated conj is O(n) total instead of O(n^2).
Hooked plist through first/rest/next/seq/count/peek/pop/nth/empty/empty?, the
predicates (list?/seq?/coll?/sequential?), realize-for-iteration, =, coll->cells
(concat/lazy), both printers, destructuring, and instance? tags. (list ...) and
quoted lists stay arrays; only conj/cons introduce plist nodes, so the surface
and risk stay small.
Verified: reduce-conj of 200k elements runs in ~0.4s (was effectively O(n^2)).
conformance 206/206, features 78/78 (+7 list regressions), jank 120 (+1).
Round 2 of the persistent-collections work.
Add a real 32-way branching-trie persistent vector (src/jolt/pv.janet) with a
tail buffer: O(log32 n) conj/assoc/nth/pop, with unchanged subtrees shared by
identity. Vector literals and vec/vector/conj/assoc/subvec/etc. now produce and
maintain these in the default (immutable) build, replacing the old tuple-based
vectors. Every core seq op, the destructurer, IFn application, the printers, =,
and the evaluator's literal/splice paths were taught to handle the pvec type.
Define several Clojure seq fns that were silently leaking to Janet builtins
(some, keep, interleave, flatten, mapcat, interpose) and broke once vectors
became tables; normalize collections through realize-for-iteration everywhere.
Build-time JOLT_MUTABLE flag now selects fast Janet-native mutable collections:
in that mode vectors are arrays (conj appends in place, vector? true, print []),
sharing one representation with lists. Default build is immutable.
Tests: conformance 206/206, features 71/71, jank 119 (baseline). Test helpers
normalized so Janet-level = compares against tuple literals regardless of repr.
The 2 test-load-sci failures (bit-clear/get-method) pre-date this work.
