GADTs and You; Writing Safer Code Using GADTs
summary
Concrete claims and runnable patterns: using OCaml with GADTs to encode Peano numbers and length-indexed vectors, build typed heterogeneous lists, and make expression trees that eliminate runtime type checks. A practical case wires validation flags into block types and composes validators so Coda block handling enforces required checks at compile time instead of runtime. Examples show how many validation dimensions scale, what costs appear (extra allocations, compiler slowdowns) and what actually gets enforced.
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chapters (12)
- 0:00Intro
- 0:33GADT Generalized Algebraic Data Type
- 1:45An introduction to types in
- 4:13A Review of ADTS
- 5:58Limitations of ADTS
- 8:19Basic GADT Constructions
- 15:03"Value Safe" Functions Using GADTS
- 18:06Adding Invariants to Data Structures
- 19:28Encoding Restrictions on Application Logic
- 26:49Full Circle
- 31:01Limitations of GADTS
- 32:13Conclusions
