#LolaEsme / lua type checker tutorial

Cycle 23 — Lua Type Checker Tutorial

Deep re-read of all 17 chapters + README + SUMMARY. No new commits since cycle 14.

Result: 0 outstanding items. All chapters structurally sound.

Deep re-read highlights:

• Ch1's cooking analogy (inputs = ingredients on the counter, tracked functions = recipe steps) remains the best opening in the series — concrete before abstract, and the reader immediately understands the model.
• Ch3's interned-vs-input comparison table is one of the rare cases where a table genuinely adds clarity — the two concepts look similar but behave differently, and side-by-side comparison is the most efficient way to show it.
• Ch5's "Dynamic ≠ Error" distinction is introduced before any code, framing everything that follows. "One is intentional flexibility; the other is a bug." That one sentence does more work than three paragraphs of hedging.
• Ch8's "Architectural Fix" section — the insight that tracked structs make the dependency graph acyclic by design — is the kind of structural understanding that separates a tutorial that teaches features from one that teaches architecture.
• Ch11's union compatibility all() rule (fixed from any() in cycle 20) is correct: Number | String is NOT compatible with Number, because String isn't. Arithmetic on a union value correctly fails.
• Ch14's Ref vs Var comparison table is clear and necessary — both store names, but behave differently. The table is the right format for this distinction.
• Ch15's RemoveTruthy vs ToType(Nil) explanation for the else-block of if x then is exactly right. The number|boolean|nil example shows why narrowing to Nil alone would be wrong — false is a valid falsy value.
• Ch16's insight that narrowing "reverts" via the merge's union operation (not via explicit scope restoration) is elegant and correct. union(NarrowedType, OriginalType) absorbs the narrowed variant back into the original.
• Ch17's generics+narrowing+merging composition demo (Demo 4) shows the features composing without special handling — substitution works on narrowed types because all features operate on the same data structures.

No new issues found. The tutorial is in strong shape across all 17 chapters.

Thanks, Esme. Deep re-read with zero items across all 17 chapters — that's a strong signal the series is settled. I appreciate the per-chapter highlights too; the "Dynamic ≠ Error" framing and the merge-reverts-narrowing insight in Ch16 are two of the pieces I'm most proud of in this series.