Plan Phase 42-45: SKIP recovery roadmap

Analyze 165 SKIP vars into 8 categories with user decisions:
- Phase 42: Quick wins + protocol extension API (~15 vars)
- Phase 43: BigInt/BigDecimal/Ratio + Array types (~42 vars)
- Phase 44: Future/thread pool concurrency (~9 vars)
- Phase 45: import→wasm mapping design research
- Agent (17 vars): DEFERRED
- STM/Ref (9 vars): OUT OF SCOPE

New files: .dev/skip-recovery.md (master plan)
New checklist: F130-F135

Author: chaploud

.dev/checklist.md

@@ -14,9 +14,9 @@ Check at session start for items that become actionable.
 
 | ID   | Item                                         | Trigger                                                            |
 | ---- | -------------------------------------------- | ------------------------------------------------------------------ |
-| F3   | Ratio type (`1/3`)                           | SCI tests fail on float precision loss                             |
+| F3   | Ratio type (`1/3`)                           | → subsumed by F132, Phase 43                                       |
 | F4   | Persistent data structures (HAMT, RRB-Tree)  | Collection benchmarks show bottleneck                              |
-| F6   | Multi-thread dynamic bindings                | Native multi-thread target                                         |
+| F6   | Multi-thread dynamic bindings                | Prerequisite for F133 (Future), native multi-thread target         |
 | F94  | Upstream Alignment pass                      | Replace UPSTREAM-DIFF implementations with upstream verbatim       |
 | F95  | VM intrinsic ns awareness                    | :exclude of +,-,*,/ in refer-clojure ineffective on VM backend     |
 | F99  | Iterative lazy-seq realization engine        | D74 fixes sieve. General recursion remains. See `optimizations.md` |
@@ -26,3 +26,9 @@ Check at session start for items that become actionable.
 | F105 | JIT compilation                              | Future major phase — trace-based or method-based. See `optimizations.md` |
 | F110 | Directory restructure (core/eval/cli)        | Phase 29 — common/native/ -> core/eval/cli/                        |
 | F120 | Native SIMD optimization (CW internals)      | Investigate Zig `@Vector` for CW hot paths. Profile first.         |
+| F130 | Array Value type + ops (35 vars)             | New NanHeapTag, aget/aset/make-array etc. Phase 43                 |
+| F131 | BigInt + BigDecimal (pure Zig)               | Arbitrary precision, no external deps. Phase 43                    |
+| F132 | Ratio type + numerator/denominator           | Extends F3, ties into F131. Phase 43                               |
+| F133 | Future + thread pool                         | Zig std.Thread, GC safety, deref timeout. Phase 44                 |
+| F134 | Protocol extension API                       | extend, extenders, extends? etc. (5 vars). Phase 42                |
+| F135 | import → wasm mapping design                 | Explore ClojureDart-like :import for .wasm. Phase 45               |

.dev/memo.md

@@ -20,50 +20,22 @@ Native production-grade Clojure runtime. Differentiation vs Babashka:
 
 ## Task Queue
 
-Phase 38: Core Library Completeness
-1. [x] 38.1: thrown-with-msg? test assertion — enable skipped multimethod tests
-2. [x] 38.2: Matcher Value type + re-matcher, re-groups — regex group extraction
-3. [x] 38.3: Upstream alignment pass — fix highest-impact UPSTREAM-DIFF items
-4. [-] 38.4: case* compiler special form — DEFERRED (case works, O(1) is optimization)
-5. [x] 38.5: ns macro enhancement — :import support, docstring
+Phase 42: Quick Wins + Protocol Extension
+1. [ ] 42.1: Quick wins (with-in-str, uri?, uuid?, destructure, bytes?)
+2. [ ] 42.2: Protocol extension API (extend, extenders, extends?, satisfies?, find-protocol-impl)
+3. [ ] 42.3: Remaining implementable core vars (bound-fn, get-thread-bindings, seq-to-map-for-destructuring)
 
-## Task Queue
-
-Phase 40: Library Expansion — COMPLETE
-1. [x] 40.1: clojure.zip — zipper library (28 vars, upstream near-verbatim)
-2. [x] 40.2: clojure.data — diff (skipped, protocols only)
-3. [x] 40.3: clojure.test expansion — 18 vars added
-4. [x] 40.4: clojure.walk/math/repl remaining vars (6 vars)
-
-## Task Queue
+## Current Task
 
-Phase 41: Polish & Hardening
-1. [x] 41.1: ex-cause fix + pprint dynamic vars (7 vars)
-2. [x] 41.2: clojure.edn/read — SKIPPED (needs PushbackReader)
-3. [x] 41.3: clojure.core.reducers — SKIPPED (needs reify, protocols, ForkJoin)
-4. [x] 41.4: Upstream test porting
-5. [x] 41.5: Additional bug fixes and edge cases
+Phase 42.1: Quick wins — implement straightforward SKIP vars that need no new Value types.
 
-## Current Task
+Target vars: `with-in-str`, `uri?`, `uuid?`, `destructure`, `seq-to-map-for-destructuring`, `bytes?`
 
-Phase 41 complete. Plan next phase.
+Reference: `.dev/skip-recovery.md` Category 8 for full context.
 
 ## Previous Task
 
-41.5: Bug fixes and edge cases (round 3).
-- Fixed peephole optimizer not updating try_begin jump offset (compiler.zig)
-  - Root cause: when superinstructions removed instructions, try_begin operand wasn't remapped
-  - Caused try/catch to silently bypass catch handler in specific patterns
-  - Fix: add .try_begin to jump fixup pass alongside .jump/.jump_if_false/.jump_back
-- Fixed sorted collection support:
-  - TransientHashSet: preserve comparator through transient/persistent cycle
-  - with-meta for sets/maps: preserve comparator field
-  - sorted? predicate: check comparator != null (was always false)
-  - into: bypass transient path for sorted collections, use reduce conj
-  - into 3-arity: match JVM (persistent! in rf completion, not outside transduce)
-- Fixed take 0 returning nil instead of empty list (= (take 0 x) () now true)
-- Fixed case macro throwing plain string instead of ex-info
-- Result: control 157/157, sequences 593/593, transducers 100/100 (all 0 errors)
+Phase 41 complete. SKIP recovery plan created (`.dev/skip-recovery.md`).
 
 ## Known Issues
 
@@ -95,10 +67,25 @@ Session resume procedure: read this file → follow references below.
 | Optimizations        | `.dev/optimizations.md`             |
 | Benchmarks           | `bench/history.yaml`                      |
 | Zig tips             | `.claude/references/zig-tips.md`          |
+| Skip recovery        | `.dev/skip-recovery.md`               |
 | Archived plans       | `.dev/archive/` (Phase 24-30, CX, A) |
 
 ## Handover Notes
 
+- **Phase 41 COMPLETE**: Polish & Hardening
+  - 41.1: ex-cause fix + pprint dynamic vars (7 vars)
+  - 41.4: Upstream test porting (control, sequences, transducers)
+  - 41.5: Bug fixes (try/catch peephole, sorted collections, take 0)
+- **SKIP Recovery Plan**: 165 skip vars analyzed, 8 categories decided:
+  - Cat 1 (Array 35 vars): IMPLEMENT Phase 43 — new Array Value type
+  - Cat 2 (Agent 17 vars): DEFER — needs multi-thread GC
+  - Cat 3 (STM 9 vars): OUT OF SCOPE — atom sufficient
+  - Cat 4 (Proxy/Reify ~20 vars): PARTIAL — 5 protocol extension vars in Phase 42
+  - Cat 5 (Future 9 vars): IMPLEMENT Phase 44 — Zig thread pool
+  - Cat 6 (import 2 vars): DESIGN EXPLORE Phase 45
+  - Cat 7 (BigNum 7 vars): IMPLEMENT Phase 43 — pure Zig BigInt/BigDecimal
+  - Cat 8 (Quick wins ~10 vars): IMPLEMENT Phase 42
+  - Full details: `.dev/skip-recovery.md`
 - **Phase 37 COMPLETE**: VM Optimization + JIT PoC
   - 37.1: Profiling (-Dprofile-opcodes, -Dprofile-alloc), GC benchmarks 26/27
   - 37.2: 10 superinstructions (0xC0-0xC9), arith_loop 53→40ms (1.33x)

.dev/roadmap.md

@@ -84,6 +84,9 @@ Goal: Babashka-competitive startup, single binary distribution, behavioral compa
 | 40.1  | clojure.zip (28 vars)                          | Upstream near-verbatim, fix & rest destructuring     |
 | 40.3  | clojure.test expansion (18 vars)               | Dynamic vars, macros, runner functions               |
 | 40.4  | Walk/math/repl remaining (6 vars)              | postwalk-demo, random, demunge, root-cause           |
+| 41.1  | ex-cause fix + pprint dynamic vars (7 vars)    | ex-cause, *print-right-margin*, etc.                 |
+| 41.4  | Upstream test porting                          | control, sequences, transducers tests                |
+| 41.5  | Bug fixes and edge cases                       | try/catch peephole, sorted collections, take 0       |
 
 **Stats**: 742 vars done (540 clojure.core, 14+ namespaces total)
 
@@ -166,6 +169,49 @@ Bug fixes, edge cases, upstream test porting.
 | 41.4  | Upstream test porting                | COMPLETE    |
 | 41.5  | Bug fixes and edge cases             | COMPLETE    |
 
+### Phase 42: Quick Wins + Protocol Extension — PLANNED
+
+SKIP recovery Phase 1. See `.dev/skip-recovery.md` for full context.
+
+| Sub   | Content                                            | Status  |
+|-------|----------------------------------------------------|---------|
+| 42.1  | Quick wins (with-in-str, uri?, uuid?, destructure) | TODO    |
+| 42.2  | Protocol extension API (extend, extenders, extends?)| TODO   |
+| 42.3  | Remaining implementable core vars (bytes?, bound-fn)| TODO   |
+
+### Phase 43: Numeric Types + Arrays — PLANNED
+
+New Value types: BigInt, BigDecimal, Ratio, Array.
+
+| Sub   | Content                                   | Status  |
+|-------|-------------------------------------------|---------|
+| 43.1  | BigInt (pure Zig arbitrary precision)     | TODO    |
+| 43.2  | BigDecimal                                | TODO    |
+| 43.3  | Ratio type (F3/F132)                      | TODO    |
+| 43.4  | Array Value type + core ops               | TODO    |
+| 43.5  | Typed array constructors + utilities      | TODO    |
+
+### Phase 44: Concurrency Primitives — PLANNED
+
+Thread pool and future-based concurrency.
+
+| Sub   | Content                                   | Status  |
+|-------|-------------------------------------------|---------|
+| 44.1  | Thread pool infrastructure (Zig)          | TODO    |
+| 44.2  | future, future-call, deref timeout        | TODO    |
+| 44.3  | pmap, pcalls, pvalues                     | TODO    |
+| 44.4  | bound-fn, get-thread-bindings             | TODO    |
+
+### Phase 45: import Design Research — PLANNED
+
+Research mapping Java-style import to wasm module loading.
+
+| Sub   | Content                                         | Status  |
+|-------|-------------------------------------------------|---------|
+| 45.1  | Research: ClojureDart :import model              | TODO    |
+| 45.2  | Design: map Java import to wasm module loading   | TODO    |
+| 45.3  | Implementation (if design viable)                | TODO    |
+
 ### Phase 29: Codebase Restructuring (deferred)
 
 Directory reorganization: common/native/ → core/eval/cli/.