erlang: ETS-lite (+13 tests)

plans/erlang-on-sx.md

@@ -92,13 +92,14 @@ Core mapping:
 ### Phase 6 — the rest
 - [x] List comprehensions `[X*2 || X <- L]` — **12 new eval tests**; generators, filters, multiple generators (cartesian), pattern-matching gens (`{ok, V} <- ...`)
 - [x] Binary pattern matching `<<A:8, B:16>>` — **21 new eval tests**; literal construction, byte/multi-byte segments, `Rest/binary` tail capture, `is_binary/1`, `byte_size/1`
-- [ ] ETS-lite (in-memory tables via SX dicts)
+- [x] ETS-lite (in-memory tables via SX dicts) — **13 new eval tests**; `ets:new/2`, `insert/2`, `lookup/2`, `delete/1-2`, `tab2list/1`, `info/2` (size); set semantics with full Erlang-term keys
 - [ ] More BIFs — target 200+ test corpus green
 
 ## Progress log
 
 _Newest first._
 
+- **2026-04-25 ETS-lite green** — Scheduler state gains `:ets` (table-name → mutable list of tuples). New `er-apply-ets-bif` dispatches `ets:new/2` (registers table by atom name; rejects duplicate name with `{badarg, Name}`), `insert/2` (set semantics — replaces existing entry with the same first-element key, else appends), `lookup/2` (returns Erlang list — `[Tuple]` if found else `[]`), `delete/1` (drop table), `delete/2` (drop key; rebuilds entry list), `tab2list/1` (full list view), `info/2` with `size` only. Keys are full Erlang terms compared via `er-equal?`. 13 new eval tests: new return value, insert true, lookup hit + miss, set replace, info size after insert/delete, tab2list length, table delete, lookup-after-delete raises badarg, multi-key aggregate sum, tuple-key insert + lookup, two independent tables. Total suite 490/490.
 - **2026-04-25 binary pattern matching green** — Parser additions: `<<...>>` literal/pattern in `er-parse-primary`, segment grammar `Value [: Size] [/ Spec]` (Spec defaults to `integer`, supports `binary` for tail). Critical fix: segment value uses `er-parse-primary` (not `er-parse-expr-prec`) so the trailing `:Size` doesn't get eaten by the postfix `Mod:Fun` remote-call handler. Runtime value: `{:tag "binary" :bytes (list of int 0-255)}`. Construction: integer segments emit big-endian bytes (size in bits, must be multiple of 8); binary-spec segments concatenate. Pattern matching consumes bytes from a cursor at the front, decoding integer segments big-endian, capturing `Rest/binary` tail at the end. Whole-binary length must consume exactly. New BIFs: `is_binary/1`, `byte_size/1`. Binaries participate in `er-equal?` (byte-wise) and format as `<<b1,b2,...>>`. 21 new eval tests: tag/predicate, byte_size for 8/16/32-bit segments, single + multi segment match, three 8-bit, tail rest size + content, badmatch on size mismatch, `=:=` equality, var-driven construction. Total suite 477/477.
 - **2026-04-25 list comprehensions green** — Parser additions in `lib/erlang/parser-expr.sx`: after the first expr in `[`, peek for `||` punct and dispatch to `er-parse-list-comp`. Qualifiers separated by `,`, each one is `Pattern <- Source` (generator) or any expression (filter — disambiguated by absence of `<-`). AST: `{:type "lc" :head E :qualifiers [...]}` with each qualifier `{:kind "gen"/"filter" ...}`. Evaluator (`er-eval-lc` in transpile.sx): right-fold builds the result by walking qualifiers; generators iterate the source list with env snapshot/restore per element so pattern-bound vars don't leak between iterations; filters skip when falsy. Pattern-matching generators are silently skipped on no-match (e.g. `[V || {ok, V} <- ...]`). 12 new eval tests: map double, fold-sum-of-comprehension, length, filter sum, "all filtered", empty source, cartesian, pattern-match gen, nested generators with filter, squares, tuple capture. Total suite 456/456.
 - **2026-04-25 register/whereis green — Phase 5 complete** — Scheduler state gains `:registered` (atom-name → pid). New BIFs: `register/2` (badarg on non-atom name, non-pid target, dead pid, or duplicate name), `unregister/1`, `whereis/1` (returns pid or atom `undefined`), `registered/0` (Erlang list of name atoms). `er-eval-send` for `Name ! Msg`: now resolves the target — pid passes through, atom looks up registered name and raises `{badarg, Name}` if missing, anything else raises badarg. Process death (in `er-sched-step!`) calls `er-unregister-pid!` to drop any registered name before `er-propagate-exit!` so monitor `{'DOWN'}` messages see the cleared registry. 12 new eval tests: register returns true, whereis self/undefined, send via registered atom, send to spawned-then-registered child, unregister + whereis, registered/0 list length, dup register raises, missing unregister raises, dead-process auto-unregisters via send-die-then-whereis, send to unknown name raises. Total suite 444/444. **Phase 5 complete — Phase 6 (list comprehensions, binary patterns, ETS) is the last phase.**