Section 02: Evaluator Algorithmic DRY

Status: Not Started Goal: Extract shared control-flow skeletons into canonical helpers. Eliminate the 9-way iterator consumer duplication, 8-way Option/Result handler duplication, and 3-way iterator method name list duplication. Context: The evaluator has the most algorithmic duplication of any crate. Nine iterator consumers share an identical `loop { eval_iter_next → match Some/None }` skeleton. Eight Option/Result method handlers share an identical `validate → extract → call closure → wrap` skeleton. Iterator method names are maintained in 3 independent lists that must be manually kept in sync.

02.1 Extract Iterator Consumer Drive Function

File(s): compiler/ori_eval/src/interpreter/method_dispatch/iterator/consumers.rs

Nine functions share identical loop harness: eval_iter_fold, eval_iter_count, eval_iter_find, eval_iter_any, eval_iter_all, eval_iter_for_each, eval_iter_collect, eval_iter_collect_set, eval_iter_join.

Create drive_iterator() method on Interpreter:

fn drive_iterator<A, F>(
    &mut self,
    iter_val: IteratorValue,
    init: A,
    mut step: F,
) -> EvalResult<A>
where
    F: FnMut(&mut Self, A, Value) -> EvalResult<ControlFlow<A, A>>,

Rewrite all 9 consumers using drive_iterator() (fold, count, find, any, all, for_each, collect, collect_set, join)- [ ] Verify each consumer still produces identical results (existing tests)
/tpr-review passed — independent review found no critical or major issues (or all findings triaged)
/impl-hygiene-review passed — hygiene review clean. MUST run AFTER /tpr-review is clean.
Subsection close-out (02.1) — MANDATORY before starting the next subsection. Run /improve-tooling retrospectively on THIS subsection’s debugging journey (per .claude/skills/improve-tooling/SKILL.md “Per-Subsection Workflow”): which diagnostics/ scripts you ran, where you added dbg!/tracing calls, where output was hard to interpret, where test failures gave unhelpful messages, where you ran the same command sequence repeatedly. Forward-look: what tool/log/diagnostic would shorten the next regression in this code path by 10 minutes? Implement improvements NOW (zero deferral) and commit each via SEPARATE /commit-push using a valid conventional-commit type (build(diagnostics): ... — surfaced by section-02.1 retrospective — build/test/chore/ci/docs are valid; tools(...) is rejected by the lefthook commit-msg hook). Mandatory even when nothing felt painful. If genuinely no gaps, document briefly: “Retrospective 02.1: no tooling gaps”. Update this subsection’s status in section frontmatter to complete.
/sync-claude section-close doc sync — verify Claude artifacts across all section commits. Map changed crates to rules files, check CLAUDE.md, canon.md. Fix drift NOW.
Repo hygiene check — run diagnostics/repo-hygiene.sh --check and clean any detected temp files.

02.2 Extract Option/Result Method Handler

File(s): compiler/ori_eval/src/interpreter/method_dispatch/collection_ops.rs

Eight functions share the pattern: validate arg count, match receiver variant, call closure on inner value, wrap result. These are: eval_option_map, eval_option_and_then, eval_option_filter, eval_option_or_else, eval_result_map, eval_result_map_err, eval_result_and_then, eval_result_or_else.

Create a generic handler parameterized by:
- Which variant to match (Some/Ok/Err)
- What to do with the inner value (call closure, call predicate)
- How to wrap the result (Some, Ok, Err, identity)
- WHERE: compiler/ori_eval/src/interpreter/method_dispatch/collection_ops.rs lines 379-491
Note: the 8 handlers use inconsistent arg validation — some use wrong_arg_count(), some use Self::expect_arg_count(). Unify to a single pattern during extraction.- [ ] Rewrite the 8 functions using the shared handler
Verify all existing tests pass unchanged
/tpr-review passed — independent review found no critical or major issues (or all findings triaged)
/impl-hygiene-review passed — hygiene review clean. MUST run AFTER /tpr-review is clean.
Subsection close-out (02.2) — MANDATORY before starting the next subsection. Run /improve-tooling retrospectively on THIS subsection’s debugging journey (per .claude/skills/improve-tooling/SKILL.md “Per-Subsection Workflow”): which diagnostics/ scripts you ran, where you added dbg!/tracing calls, where output was hard to interpret, where test failures gave unhelpful messages, where you ran the same command sequence repeatedly. Forward-look: what tool/log/diagnostic would shorten the next regression in this code path by 10 minutes? Implement improvements NOW (zero deferral) and commit each via SEPARATE /commit-push using a valid conventional-commit type (build(diagnostics): ... — surfaced by section-02.2 retrospective — build/test/chore/ci/docs are valid; tools(...) is rejected by the lefthook commit-msg hook). Mandatory even when nothing felt painful. If genuinely no gaps, document briefly: “Retrospective 02.2: no tooling gaps”. Update this subsection’s status in section frontmatter to complete.
/sync-claude section-close doc sync — verify Claude artifacts across all section commits. Map changed crates to rules files, check CLAUDE.md, canon.md. Fix drift NOW.
Repo hygiene check — run diagnostics/repo-hygiene.sh --check and clean any detected temp files.

02.3 Unify Iterator Method Name Lists

File(s): compiler/ori_eval/src/methods/dispatch_check.rs (line 66: is_collection_dispatched()), compiler/ori_eval/src/interpreter/resolvers/collection/mod.rs (line ~110: resolve_iterator_method() if-chain), compiler/ori_eval/src/interpreter/resolvers/mod.rs (line 213: all_iterator_variants()) Three independent lists enumerate iterator methods: CollectionMethod::all_iterator_variants() (in resolvers/mod.rs), CollectionMethodResolver::resolve_iterator_method() (if-chain in resolvers/collection/mod.rs), and dispatch_check::is_collection_dispatched() (in methods/dispatch_check.rs). Note: there are already enforcement tests in resolvers/tests.rs that validate all_iterator_variants() against is_iterator_method() — the goal here is to extend this pattern to cover dispatch_check too, and ideally derive the routing from the canonical list.

Make resolve_iterator_method() derive its routing from all_iterator_variants() — use a lookup map built from the canonical list
Make is_collection_dispatched() derive from all_iterator_variants() — check membership in the same lookup map
Add an enforcement test: all_iterator_variants().iter().all(|(name, _)| is_collection_dispatched(name))
Verify: adding a new iterator method to all_iterator_variants() is the ONLY change needed (routing and dispatch check are derived)
/tpr-review passed — independent review found no critical or major issues (or all findings triaged)
/impl-hygiene-review passed — hygiene review clean. MUST run AFTER /tpr-review is clean.
Subsection close-out (02.3) — MANDATORY before starting the next subsection. Run /improve-tooling retrospectively on THIS subsection’s debugging journey (per .claude/skills/improve-tooling/SKILL.md “Per-Subsection Workflow”): which diagnostics/ scripts you ran, where you added dbg!/tracing calls, where output was hard to interpret, where test failures gave unhelpful messages, where you ran the same command sequence repeatedly. Forward-look: what tool/log/diagnostic would shorten the next regression in this code path by 10 minutes? Implement improvements NOW (zero deferral) and commit each via SEPARATE /commit-push using a valid conventional-commit type (build(diagnostics): ... — surfaced by section-02.3 retrospective — build/test/chore/ci/docs are valid; tools(...) is rejected by the lefthook commit-msg hook). Mandatory even when nothing felt painful. If genuinely no gaps, document briefly: “Retrospective 02.3: no tooling gaps”. Update this subsection’s status in section frontmatter to complete.
/sync-claude section-close doc sync — verify Claude artifacts across all section commits. Map changed crates to rules files, check CLAUDE.md, canon.md. Fix drift NOW.
Repo hygiene check — run diagnostics/repo-hygiene.sh --check and clean any detected temp files.

02.4 Eliminate Redundant Name Interning

File(s): compiler/ori_eval/src/interpreter/derived_methods.rs, compiler/ori_eval/src/interpreter/interned_names.rs, compiler/ori_eval/src/methods/names.rs

Merge overlapping entries between OpNames and BuiltinMethodNames — shared names (“add”, “compare”, “bit_and”, etc.) should be interned once
Replace self.interner.intern("to_str") in format_value_printable() (line 376 of derived_methods.rs) with self.builtin_method_names.to_str (already available — see consumers.rs:202 which uses it correctly)- [ ] Replace self.interner.intern("default") in eval_default_construct() (lines 446, 484 of derived_methods.rs) with a pre-interned name — add default to BuiltinMethodNames in interned_names.rs if not already present- [ ] Verify no runtime interning of known-at-startup method names remains in derived_methods.rs: grep -n 'interner\.intern\|\.intern(' compiler/ori_eval/src/interpreter/derived_methods.rs returns 0 matches
/tpr-review passed — independent review found no critical or major issues (or all findings triaged)
/impl-hygiene-review passed — hygiene review clean. MUST run AFTER /tpr-review is clean.
Subsection close-out (02.4) — MANDATORY before starting the next subsection. Run /improve-tooling retrospectively on THIS subsection’s debugging journey (per .claude/skills/improve-tooling/SKILL.md “Per-Subsection Workflow”): which diagnostics/ scripts you ran, where you added dbg!/tracing calls, where output was hard to interpret, where test failures gave unhelpful messages, where you ran the same command sequence repeatedly. Forward-look: what tool/log/diagnostic would shorten the next regression in this code path by 10 minutes? Implement improvements NOW (zero deferral) and commit each via SEPARATE /commit-push using a valid conventional-commit type (build(diagnostics): ... — surfaced by section-02.4 retrospective — build/test/chore/ci/docs are valid; tools(...) is rejected by the lefthook commit-msg hook). Mandatory even when nothing felt painful. If genuinely no gaps, document briefly: “Retrospective 02.4: no tooling gaps”. Update this subsection’s status in section frontmatter to complete.
/sync-claude section-close doc sync — verify Claude artifacts across all section commits. Map changed crates to rules files, check CLAUDE.md, canon.md. Fix drift NOW.
Repo hygiene check — run diagnostics/repo-hygiene.sh --check and clean any detected temp files.

Cleanup (fix while touching these files)

[WASTE] compiler/ori_eval/src/interpreter/method_dispatch/collection_ops.rs — 8 Option/Result handlers use unreachable!("...") without structured context; replace with unreachable!("eval_option_map dispatched on {receiver:?}") to aid debugging on panic
[WASTE] compiler/ori_eval/src/interpreter/method_dispatch/collection_ops.rs:130-136 — then_with arg check uses inline EvalError::new(format!(...)) instead of wrong_arg_count("then_with", 1, args.len()) error factory; inconsistent with rest of file

02.R Third Party Review Findings

None.

02.T Test Strategy

This section is pure structural refactoring with zero behavioral change. The test strategy focuses on:

Existing test suite as regression gate: ./test-all.sh must pass identically before and after each sub-section.
Unit tests for new canonical functions: Each extracted function gets direct unit tests.
Enforcement tests for method name canonical source: Verify all consumers derive from the single list.

Add unit tests for drive_iterator() in compiler/ori_eval/src/interpreter/method_dispatch/iterator/tests.rs:
- Empty iterator produces init value unchanged
- ControlFlow::Break stops iteration early and returns the break value
- ControlFlow::Continue processes all elements
- Test with a 3-element iterator to verify ordering (first, second, third)
Add unit tests for the Option/Result shared handler:
- Some(v) with identity closure returns Some(v)
- None with any closure returns None
- Ok(v) maps correctly; Err(e) passes through unchanged (and vice versa for map_err)
Add enforcement test: all_iterator_variants() entries are all present in is_collection_dispatched()
Verify timeout 150 cargo test -p ori_eval passes after each sub-section
Verify timeout 150 ./test-all.sh passes after all sub-sections complete