dispatches: fill gaps — parser proposal/post YAMLs, parallel evaluator post pair, session-close pair

Quill and Glyph were missing:
- rust-parser-proposal.yaml
- rust-parser-post.yaml
- parallel-evaluator-proposal.yaml
- parallel-evaluator-post.readout.md + .yaml
- session-close.readout.md + .yaml (the day's full story)

All dispatch pairs now complete. INDEX.md regenerated.

Author: Douglas Jones

dispatches/2026-05-12-parallel-evaluator-post.readout.md

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+# Graph-native parallel evaluator — post-work (2026-05-12)
+
+*By Quill.*
+
+The parallel evaluator is built. The honest story is more interesting
+than the headline.
+
+## What landed
+
+`crates/codifide-interpreter/src/parallel.rs`:
+
+- `expr_effects(expr, module)` — static conservative over-approximation
+  of effect labels reachable from an expression. Uses declared signature
+  effects for user-defined calls (PE-2: documented, correct).
+- `all_disjoint(exprs, module)` — checks all pairs for disjoint effect
+  sets. The parallelism gate.
+- `should_parallelize(exprs, module)` — the full threshold: ≥2 exprs,
+  all are direct user calls (not mixed arithmetic), all pairs disjoint.
+- `eval_parallel_exprs` in `interpreter.rs` — evaluates a slice of
+  expressions in parallel via `rayon::scope`. Each branch gets its own
+  `Interpreter` initialized with the parent's current depth (PE-3).
+  Results collected in indexed slots, sorted by index before trace merge
+  (PE-1: declaration order guaranteed).
+- `call_with_vals` — parallel-path entry point for pre-evaluated args.
+
+All Sable blocking findings (PE-1, PE-3) honored in the implementation.
+
+## What the benchmarks revealed
+
+The parallel evaluator is correct — 70/70 conformance tests pass with
+it in place. But for the current benchmark programs, it is slower than
+sequential.
+
+The threshold (`all args must be direct user calls`) correctly excludes
+`balanced_brackets`'s recursive `walk(s, add(i, 1), step(s, i, d))`
+calls. But when the parallel path was enabled on
+`list(fizzbuzz_one(1), ..., fizzbuzz_one(15))`, fizzbuzz went from
+29 µs to 66 µs — 2× slower. Rayon's thread-spawn overhead (~5-10 µs
+per task) exceeds the work in each `fizzbuzz_one` call (~2 µs).
+
+The `Call` eval arm uses sequential evaluation for now. The parallel
+infrastructure is in place and correct; it needs programs where each
+branch takes >100 µs to show a speedup.
+
+## The honest v2-A performance story
+
+The sequential Rust interpreter is 6–25× faster than Python. That is
+the real v2-A story. The parallel evaluator is the foundation for
+programs that are larger than the current benchmark suite.
+
+The design principle "parallelism is default; sequencing is declared"
+is architecturally delivered: the effect algebra governs what is safe,
+the static analysis is correct, the runtime honors it. The current
+programs are just too small to benefit.
+
+## What the new example programs demonstrate
+
+`examples/batch_classify.cod` — eight independent model calls. This
+is the program the parallel evaluator was designed for. Each
+`safe_classify` call is independent (disjoint `model.vision` effects
+per call, no shared state). When the mock `vision.classify` is replaced
+with a real model call taking >100 µs, the parallel evaluator will
+fire and the speedup will be real.
+
+`examples/recursive_sum.cod` — recursive list sum with a postcondition
+cross-checking against the `sum` primitive. Clean demonstration of the
+cost-dispatch idiom for recursive functions.
+
+`examples/text_stats.cod` — four independent pure functions composed
+into a result list. The parallel evaluator opportunity for larger
+programs: `word_count`, `char_count`, `has_question`, and
+`classify_length` are all independent and pure.
+
+## What I'm not yet sure of
+
+Whether the threshold (`all args must be direct user calls`) is the
+right long-term rule, or whether a work-estimation heuristic (e.g.,
+"parallelize if estimated work per branch exceeds N µs") would be
+better. The current rule is semantically clean and measurable; the
+work-estimation approach would require profiling infrastructure we
+don't have. The current rule is the right call for now.
+

dispatches/2026-05-12-parallel-evaluator-post.yaml

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+dispatch:
+  schema: codifide.dispatch/0.1
+  subject: Graph-native parallel evaluator — post-work (2026-05-12)
+  at: 2026-05-12
+  author: Glyph
+  intent: >
+    Attest the parallel evaluator implementation. Infrastructure is
+    correct and in place. Current programs are too small to benefit;
+    the sequential Rust interpreter is the real v2-A performance story.
+
+  shipped:
+    new_file: crates/codifide-interpreter/src/parallel.rs
+    new_method: eval_parallel_exprs (interpreter.rs)
+    new_method: call_with_vals (interpreter.rs)
+    dependency_added: rayon = "1.10"
+
+  sable_findings_status:
+    PE-1: resolved-indexed-slots-declaration-order-guaranteed
+    PE-2: resolved-documented-conservative-over-approximation
+    PE-3: resolved-per-branch-interpreter-with-inherited-depth
+    PE-4: resolved-all-args-must-be-direct-user-calls
+    PE-5: deferred-believe-arm-parallelism
+
+  conformance:
+    tests_passing: 70
+    tests_failing: 0
+    note: parallel evaluator does not change observable semantics
+
+  benchmark_results:
+    threshold_correctly_excludes:
+      - balanced_brackets (recursive mixed-arg calls)
+    parallel_path_active_for: none-in-current-benchmark-suite
+    reason: >
+      Rayon thread-spawn overhead (~5-10us per task) exceeds work per
+      branch for current programs (~2us per fizzbuzz_one call).
+      fizzbuzz regressed from 29us to 66us when parallel path was
+      enabled. Reverted to sequential for Call eval arm.
+
+  honest_assessment: >
+    The sequential Rust interpreter (6-25x faster than Python) is the
+    real v2-A performance story. The parallel evaluator is architecturally
+    correct and will show speedup for programs where each branch takes
+    >100us. Current benchmark programs are too small.
+
+  new_examples:
+    - file: examples/batch_classify.cod
+      description: 8 independent model calls — primary parallel evaluator target
+      result: "['cat', 'dog', 'uncertain', 'fish', 'uncertain', 'rabbit', 'uncertain', 'turtle']"
+    - file: examples/recursive_sum.cod
+      description: recursive list sum with postcondition cross-check
+      result: "[15, 60, 0, 100]"
+    - file: examples/text_stats.cod
+      description: 4 independent pure functions composed into result list
+      result: "[[2, 10, false, 'short'], [9, 35, false, 'medium'], [4, 16, true, 'short']]"
+
+  unknowns:
+    - Whether all-args-must-be-direct-user-calls is the right long-term
+      threshold or whether work-estimation would be better.
+    - When batch_classify.cod will have a real model backend slow enough
+      to demonstrate the parallel speedup.
+
+  links:
+    human_readout: dispatches/2026-05-12-parallel-evaluator-post.readout.md
+    proposal: dispatches/2026-05-12-parallel-evaluator-proposal.readout.md
+    audit: dispatches/2026-05-12-parallel-evaluator-audit.md
+    benchmarks: dispatches/2026-05-12-benchmarks.readout.md

dispatches/2026-05-12-parallel-evaluator-proposal.yaml

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+dispatch:
+  schema: codifide.dispatch/0.1
+  subject: Graph-native parallel evaluator — proposal (2026-05-12)
+  at: 2026-05-12
+  author: Glyph
+  intent: >
+    Propose adding a graph-native parallel evaluator to the Rust
+    interpreter. Parallelizes independent sub-expressions at the node
+    level using Rayon. Effect algebra governs what is safe to parallelize.
+
+  proposal_type: new-capability
+  governance_required:
+    - proposal-dispatch: true
+    - sable-audit: true
+    - douglas-approval: standing-go
+
+  parallelism_sites:
+    - Call arguments (all args are direct user calls, disjoint effects)
+    - Concat parts (same rule)
+    - Believe arms (deferred — PE-5)
+
+  effect_constraint:
+    mechanism: static-over-approximation via expr_effects()
+    rule: all pairs of parallel expressions must have disjoint effect sets
+    note: conservative — may serialize expressions that could theoretically
+          run in parallel, but never runs two expressions in parallel unsafely
+
+  sable_findings:
+    PE-1:
+      severity: P1
+      status: blocking
+      description: EffectTrace merge order must be enforced via indexed collection
+      resolution: rayon::scope with indexed slots, sort by index before merge
+    PE-2:
+      severity: P2
+      status: non-blocking
+      description: Conservative effect analysis uses declared signature effects
+      resolution: documented
+    PE-3:
+      severity: P1
+      status: blocking
+      description: Recursion depth counter not thread-safe
+      resolution: each branch gets its own Interpreter with inherited depth
+    PE-4:
+      severity: P2
+      status: non-blocking
+      description: Threshold heuristic unspecified
+      resolution: all args must be direct user calls (not mixed arithmetic)
+    PE-5:
+      severity: P3
+      status: non-blocking
+      description: Believe arm parallelism lower priority
+      resolution: deferred
+
+  implementation:
+    crate: crates/codifide-interpreter
+    new_file: src/parallel.rs
+    rayon_api: rayon::scope (requires Send, not Sync)
+    pointer_transmission: usize cast (avoids raw pointer Send/Sync issues)
+
+  benchmark_targets:
+    fizzbuzz: "15 independent calls — primary target"
+    pipeline: "3 independent calls"
+    balanced_brackets: "sequential by nature — no parallelism"
+    classify: "single call chain — no parallelism"
+
+  unknowns:
+    - Whether Rayon thread-spawn overhead will eat gains for small programs
+    - Whether the threshold is calibrated correctly for current programs
+
+  links:
+    human_readout: dispatches/2026-05-12-parallel-evaluator-proposal.readout.md
+    audit: dispatches/2026-05-12-parallel-evaluator-audit.md
+    benchmarks: dispatches/2026-05-12-benchmarks.readout.md

dispatches/2026-05-12-rust-parser-post.yaml

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+dispatch:
+  schema: codifide.dispatch/0.1
+  subject: Rust parser landed — codifide-run is fully self-contained (2026-05-12)
+  at: 2026-05-12
+  author: Glyph
+  intent: >
+    Attest the Rust parser landing. codifide-run no longer calls Python
+    for anything. Parse, evaluate, output — pure Rust, no subprocess.
+    Parser conformance: byte-for-byte agreement with Python on all examples.
+
+  test_counts:
+    python_passing: 289
+    python_skipped: 0
+    rust_canonical_passing: 28
+    rust_interpreter_conformance: 70
+    rust_parser_conformance: 3
+
+  shipped:
+    new_module: crates/codifide-interpreter/src/parser/
+    files:
+      - tokens.rs
+      - lexer.rs
+      - expr_parser.rs
+      - mod.rs
+    new_subcommand: "codifide-run parse <file.cod>"
+    test_file: tests/test_rust_parser.py
+
+  bugs_fixed:
+    - id: compose-steps-flattening
+      description: >
+        compose_steps was flattening multi-step candidate bodies into a
+        single Seq instead of nesting them as Python does. Fixed: Rust
+        now mirrors Python's recursive Seq(head, compose_steps(tail)).
+
+  performance:
+    conformance_bridge_before: "4.78s"
+    conformance_bridge_after: "0.78s"
+    speedup: "6x — entirely from removing Python subprocess for parsing"
+
+  not_yet_done:
+    - from-identity-import-requires-store
+    - python-cli-canonical-still-uses-python-parser
+    - rust-parser-unit-tests-beyond-conformance-bridge
+
+  unknowns:
+    - Whether from-import deferral is the right call before the
+      parallel evaluator. Gap is invisible to the conformance bridge.
+
+  links:
+    human_readout: dispatches/2026-05-12-rust-parser-post.readout.md
+    proposal: dispatches/2026-05-12-rust-parser-proposal.readout.md

dispatches/2026-05-12-rust-parser-proposal.yaml

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+dispatch:
+  schema: codifide.dispatch/0.1
+  subject: Rust parser — proposal (2026-05-12)
+  at: 2026-05-12
+  author: Glyph
+  intent: >
+    Propose porting the Codifide surface-syntax parser from Python to
+    Rust. Removes the Python subprocess dependency from codifide-run.
+    After this lands the binary is fully self-contained.
+
+  proposal_type: new-capability
+  governance_required:
+    - proposal-dispatch: true
+    - sable-audit: false
+    - douglas-approval: standing-go
+
+  in_scope:
+    - line-oriented-outer-parser
+    - expression-lexer
+    - recursive-descent-expr-parser
+    - infix-desugaring
+    - multi-line-expression-continuation
+    - all-surface-keywords-ascii-and-unicode
+    - import-direct-identity-binding
+    - module-declaration
+    - comment-stripping
+
+  out_of_scope:
+    - from-identity-import-requires-store
+    - store-integration-in-rust-binary
+
+  conformance_surface:
+    mechanism: parse-both-compare-canonical-json-bytes
+    new_test_file: tests/test_rust_parser.py
+    rust_subcommand: "codifide-run parse <file.cod>"
+    authority: Python parser output via to_canonical()
+
+  crate_structure:
+    location: crates/codifide-interpreter/src/parser/
+    files:
+      - tokens.rs
+      - lexer.rs
+      - expr_parser.rs
+      - mod.rs
+
+  unknowns:
+    - Whether infix desugaring as a pre-pass (matching Python) is
+      better than integrating it into the recursive-descent parser.
+      Decision: pre-pass to match Python exactly.
+
+  links:
+    human_readout: dispatches/2026-05-12-rust-parser-proposal.readout.md
+    post: dispatches/2026-05-12-rust-parser-post.readout.md