The document discusses the benefits and challenges of proof-driven development using the Coq proof assistant. It describes how Coq can be used to formally prove properties about code during development. However, it also notes that Coq has limitations when dealing with large numbers, which can cause stack overflows. It also discusses using Coq to formally specify the MessagePack serialization format and prove properties about it.

1. The fun of proof driven development
@mzp /
Reject
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2. ( )
• @mzp /
•
•
•
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3. Reject
↓ Ruby
Ruby
@Dominion525
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4. Ruby
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5. Ruby
• Coq to Ruby
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6. Ruby
• Coq to Ruby
• Git
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7. Ruby
• Coq to Ruby
• Git
• Perl
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8. • Reject Coq to
Ruby
• Reject
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9. @mzp /
Reject
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10. (
)
‘‘
Coq Merge Sort -
http://d.hatena.ne.jp/yoshihiro503/20090923/p1
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11. MessagePack
• @frsyuki
•
•
(Java,C++,Ruby, Python,Perl,Haskell)
• RPC
OCaml
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12. •
•
•
• Base64
•
•
Coq
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13. MessagePack for OCaml
•
• https://github.com/mzp/msgpack-ocaml
•
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14. 11

15. 12

16. Coq
(* *)
Infix "@@" := atat (right associativity, at level 75).
(* *)
Notation "[ ]" := nil : list_scope.
(* ( : [1; 2; 3]) (!) *)
Notation "[ a ; .. ; b ]" := (a :: .. (b :: []) ..) : list_scope.
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17. TDD
• TDD =
• Coq =
= !
•
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18. • :
• : Twitter
• Twitter Coq
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19. • 2 3
• 255 int -> uchar uchar->int
• Coq Anarchy Proof( )
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20. : Scala
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21. 18

22. •
•
• !
•
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23. • !
•
•
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24. •
• :
• : OCaml
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25. The darkside of the Proof Driven Development
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26. Coq < Check 5001.
Warning: Stack overflow or segmentation fault happens when
working with large
numbers in nat (observed threshold may vary from 5000 to
70000 depending on
your system limits and on the command executed).
5001 : nat
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27. ?
• nat
•
Inductive nat : Set :=
O (* 0 *)
| S (_ : nat) (* 1 *)
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28. • MessagePack 2^n
(* : 2^n * 2^m = 2^(n+m) *)
Lemma pow_add: forall n m,
pow n * pow m = pow (n + m).
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29. Definition Soundness obj1 x := forall obj2,
Serialized obj1 x ->
Serialized obj2 x ->
Valid obj1 ->
Valid obj2 ->
obj1 = obj2.
•
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30. CI
• (CI)
•
(1GB )
• VPS orz
• Coq on EC2
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31. • MessagePack for OCaml 2
• 4000
↓ 2
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32. • MessagePack for OCaml
•“ ”
•
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