Recover agent-loop progress: lua/prolog/forth/erlang/haskell phases 1-2

Salvaged from worktree-agent-* branches killed during sx-tree MCP outage:
- lua: tokenizer + parser + phase-2 transpile (~157 tests)
- prolog: tokenizer + parser + unification (72 tests, plan update lost to WIP)
- forth: phase-1 reader/interpreter + phase-2 colon/VARIABLE (134 tests)
- erlang: tokenizer + parser (114 tests)
- haskell: tokenizer + parse tests (43 tests)

Cherry-picked file contents only, not branch history, to avoid pulling in
unrelated ocaml-vm merge commits that were in those branches' bases.

plans/haskell-on-sx.md

@@ -54,11 +54,11 @@ Key mappings:
 ## Roadmap
 
 ### Phase 1 — tokenizer + parser + layout rule
-- [ ] Tokenizer: reserved words, qualified names, operators, numbers (int, float, Rational later), chars/strings, comments (`--` and `{-` nested)
+- [x] Tokenizer: reserved words, qualified names, operators, numbers (int, float, Rational later), chars/strings, comments (`--` and `{-` nested)
 - [ ] Layout algorithm: turn indentation into virtual `{`, `;`, `}` tokens per Haskell 98 §10.3
 - [ ] Parser: modules, imports (stub), top-level decls, type sigs, function clauses with patterns + guards + where-clauses, expressions with operator precedence, lambdas, `let`, `if`, `case`, `do`, list comp, sections
 - [ ] AST design modelled on GHC's HsSyn at a surface level
-- [ ] Unit tests in `lib/haskell/tests/parse.sx`
+- [x] Unit tests in `lib/haskell/tests/parse.sx` (43 tokenizer tests, all green)
 
 ### Phase 2 — desugar + eager-ish eval + ADTs (untyped)
 - [ ] Desugar: guards → nested `if`s; `where` → `let`; list comp → `concatMap`-based; do-notation stays for now (desugared in phase 3)
@@ -107,7 +107,27 @@ Key mappings:
 
 _Newest first._
 
-- _(not started)_
+- **2026-04-24** — Phase 1: Haskell 98 tokenizer (`lib/haskell/tokenizer.sx`, 490 lines)
+  covering idents (lower/upper/qvarid/qconid), 23 reserved words, 11 reserved ops,
+  varsym/consym operator chains, integer/hex/octal/float literals incl. exponent
+  notation, char + string literals with escape sequences, nested `{- ... -}` block
+  comments with depth counter, `-- ... EOL` line comments (respecting the
+  "followed by symbol = not a comment" Haskell 98 rule), backticks, punctuation,
+  and explicit `newline` tokens for the upcoming layout pass. 43 structural tests
+  in `lib/haskell/tests/parse.sx`, a lightweight `hk-deep=?` equality helper
+  and a custom `lib/haskell/test.sh` runner (pipes through the OCaml epoch
+  protocol, falls back to the main-repo build when run from a worktree). 43/43
+  green.
+
+  Also peeked at `/root/rose-ash/sx-haskell/` per briefing: that directory is a
+  Haskell program implementing an **SX interpreter** (Types.hs, Eval.hs,
+  Primitives.hs, etc. — ~2800 lines of .hs) — the *opposite* direction from this
+  project. Nothing to fold in.
+
+  Gotchas hit: `emit!` and `peek` are SX evaluator special forms, so every local
+  helper uses the `hk-` prefix. `cond`/`when`/`let` clauses evaluate ONLY the
+  last expression; multi-expression bodies MUST be wrapped in `(do ...)`. These
+  two together account for all the tokenizer's early crashes.
 
 ## Blockers