fed-sx-m1: Step 3b substrate fix #3 — atom_to_list/integer_to_list as Erlang charlists; list_to_* accept both (+9 net eval, 759/759)

plans/fed-sx-milestone-1.md

@@ -200,7 +200,7 @@ verify_signature(Activity, ActorState) ->
 - [ ] **3b** — *Parked behind substrate gap (see Blockers below).* Term codec + on-disk persistence: serializer/parser writing each activity as a JSONL-style line; restart-resumes-tip from the segment file.
 - [ ] **3c** — Segment rotation at size threshold + gen_server-mediated concurrent appends.
 
-**Blockers (Step 3b) — byte-level path resolved 2026-06-04:** `binary_to_list/1` and `list_to_binary/1` are now registered Erlang BIFs in `lib/erlang/runtime.sx` (Step 3b substrate fix, +9 ffi tests, 738/738 conformance). `list_to_binary` is iolist-aware: accepts nested cons of integer bytes (0-255) and/or binaries; `binary_to_list` returns a proper Erlang charlist of integers. Round-trip verified: `list_to_binary(binary_to_list(B)) =:= B`. On-disk segment writer (3b) can now build segment bytes from `[Header, IoListPayload]` and reconstruct on read — option (c) of the original workaround menu is now cheap. `$X` char literals now decode correctly **as of 2026-06-04**: the Erlang tokenizer's `(= ch "$")` branch (`lib/erlang/tokenizer.sx`) now emits the decimal char code as the token value instead of the raw `$X` text (which `parse-number` couldn't decode → nil). Plain chars use `char->integer` of the first char; the standard escape table (`\n=10 \t=9 \r=13 \s=32 \b=8 \e=27 \f=12 \v=11 \d=127 \0=0 \\=92 \"=34 \'=39`) handles `$\X` forms. So `[$h, $i | T]` patterns and `list_to_binary([$f,$e,$d])` both work end-to-end. +12 eval tests, 750/750. Combined with 3b's `binary_to_list`/`list_to_binary`, Erlang code can now read/write byte sequences and string-shaped char lists fluently. Still parked: `atom_to_list/1`/`integer_to_list/1` return SX strings rather than Erlang charlists — only blocks code that wants to do `[$0+N | _]` arithmetic on integer-to-string output or `[Lower | _]` on atom names; downstream Steps in this milestone don't need it.
+**Blockers (Step 3b) — byte-level path resolved 2026-06-04:** `binary_to_list/1` and `list_to_binary/1` are now registered Erlang BIFs in `lib/erlang/runtime.sx` (Step 3b substrate fix, +9 ffi tests, 738/738 conformance). `list_to_binary` is iolist-aware: accepts nested cons of integer bytes (0-255) and/or binaries; `binary_to_list` returns a proper Erlang charlist of integers. Round-trip verified: `list_to_binary(binary_to_list(B)) =:= B`. On-disk segment writer (3b) can now build segment bytes from `[Header, IoListPayload]` and reconstruct on read — option (c) of the original workaround menu is now cheap. `$X` char literals now decode correctly **as of 2026-06-04**: the Erlang tokenizer's `(= ch "$")` branch (`lib/erlang/tokenizer.sx`) now emits the decimal char code as the token value instead of the raw `$X` text (which `parse-number` couldn't decode → nil). Plain chars use `char->integer` of the first char; the standard escape table (`\n=10 \t=9 \r=13 \s=32 \b=8 \e=27 \f=12 \v=11 \d=127 \0=0 \\=92 \"=34 \'=39`) handles `$\X` forms. So `[$h, $i | T]` patterns and `list_to_binary([$f,$e,$d])` both work end-to-end. +12 eval tests, 750/750. Combined with 3b's `binary_to_list`/`list_to_binary`, Erlang code can now read/write byte sequences and string-shaped char lists fluently. **All three substrate gaps resolved as of 2026-06-05.** `atom_to_list/1` and `integer_to_list/1` now return Erlang charlists (cons of int char codes — standard Erlang semantics) via a new `er-string->charlist` helper in `transpile.sx`. `list_to_atom/1` and `list_to_integer/1` accept either charlists OR SX strings (back-compat via the existing `er-source-to-string` coercer). Composition works end-to-end: `list_to_binary(atom_to_list(hello)) =:= <<104,101,108,108,111>>` and `integer_to_list(N)` round-trips through `list_to_integer`. 5 existing eval tests rewritten to charlist semantics, 8 new charlist-aware tests added (759/759). The full term-codec primitive set — `binary_to_list`, `list_to_binary`, `$X`, `atom_to_list`, `integer_to_list` charlist semantics, plus existing `file:read_file`/`write_file`/`list_dir` — is now in place.
 
 **Deliverables:**
 
@@ -1003,6 +1003,7 @@ A few things still under-specified; resolve as work begins.
 Newest first. One line per sub-deliverable commit. Erlang conformance gate
 (`bash lib/erlang/conformance.sh`) must remain 729/729 on every entry.
 
+- **2026-06-05** — Step 3b substrate fix #3 (final): `atom_to_list/1` and `integer_to_list/1` now return Erlang charlists (cons-of-int-char-codes) instead of SX strings — standard Erlang semantics. New helper `er-string->charlist` in `transpile.sx`. `list_to_atom/1` and `list_to_integer/1` accept either charlists OR SX strings (back-compat via the existing `er-source-to-string` coercer, which already handles both shapes). 5 existing eval tests rewritten to match new semantics (e.g. `length(atom_to_list(hello)) =:= 5`, `hd(integer_to_list(42)) =:= 52`). 8 new charlist-coverage tests demonstrating composition: `list_to_binary(atom_to_list(ok)) =:= <<111,107>>`; `list_to_atom([$f,$o,$o])` round-trips; `list_to_integer([$1,$0,$0]) =:= 100`. Erlang conformance **759/759** (eval 397→406, +9 net). The full term-codec primitive set — `binary_to_list`/`list_to_binary` (24e3bf53), `$X` literals (3d80bd8c), and now `atom_to_list`/`integer_to_list` charlists — is in place; Step 3b on-disk segment writer can encode arbitrary Erlang activity terms (atoms, ints, binaries, tuples, lists) into byte sequences using only Erlang-native primitives.
 - **2026-06-04** — Step 3b substrate fix #2: `$X` char-literal decoding. Patched the Erlang tokenizer's `(= ch "$")` branch in `lib/erlang/tokenizer.sx` to emit the decimal char code as the integer token value instead of the raw `$X` source text (which `parse-number` couldn't decode → nil). Plain `$c` uses `char->integer` of the first char; `$\C` consults the standard Erlang escape table (`\n=10 \t=9 \r=13 \s=32 \b=8 \e=27 \f=12 \v=11 \d=127 \0=0 \\=92 \"=34 \'=39`). End-of-file after `$` decodes to 0 defensively. Probes: `$A→65`, `$0→48`, `$\n→10`, `$\\→92`, `[$h,$i]` → cons of 104/105, `list_to_binary([$f,$e,$d])` → `<<102,101,100>>`. +12 eval tests (single chars, each escape, list/binary composition with previous BIFs). Combined with substrate fix #1, Erlang code in fed-sx-m1 can now write `[$h, $i | T]` patterns AND construct/deconstruct binaries — a full term-codec primitive set. Erlang conformance **750/750** (eval 385→397). Plan Blockers note updated; remaining `atom_to_list`/`integer_to_list` charlist gap noted as low-priority for Milestone 1.
 - **2026-06-04** — Step 3b substrate fix: registered `erlang:binary_to_list/1` and `erlang:list_to_binary/1` in `lib/erlang/runtime.sx` — the byte-level half of the term-codec gap. `binary_to_list` returns a proper Erlang charlist (`er-mk-cons` chain of byte ints). `list_to_binary` is iolist-aware via a recursive `er-iolist-walk!` that accepts nil / cons / binary / integer 0-255 and flattens nested iolists (e.g. `[1, <<2,3>>, [4, [5]]]` → `<<1,2,3,4,5>>`); out-of-range bytes or non-iolist elements raise `error:badarg`. Round-trip verified: `list_to_binary(binary_to_list(B)) =:= B`. +9 ffi tests (length, hd, empty→[], flat byte_size, nested-iolist, round-trip, 3 badarg paths). On-disk segment writer (3b) now has a complete `[Header | IoListPayload] → Binary` path; the remaining two substrate gaps (`atom_to_list`/`integer_to_list` as Erlang charlists, `$X` char-literal decoding) are still parked but no longer block 3b implementation if the encoding uses byte ints directly. Erlang conformance **738/738** (ffi 28→37). Plan Blockers note for Step 3b updated to reflect the partial resolution.
 - **2026-05-28** — Step 4f-consolidate: `bootstrap:start/3(ActorId, KeySpec, ActorState)` brings up the full kernel substrate in one call — starts the registry gen_server, populates it from the canonical genesis bundle (31 entries across 7 kinds), then starts nx_kernel. Returns the kernel Pid (gen_server convention in this port returns raw Pid not `{ok, Pid}`). Tests verify whereis(nx_kernel), per-kind counts (3/10/7/3/3/2/3), registry lookup of a known entry (`create`), publish + log_tip advance. `next/tests/bootstrap_start.sh` 10/10. Erlang conformance 729/729.