[isabelle-dev] Problems with Code-Generator
RenĂ© Thiemann
rene.thiemann at uibk.ac.at
Mon Aug 12 10:53:31 CEST 2013
Dear all,
Chris and I have recently ported our libraries IsaFoR and TermFun to the development version which worked nicely, except for one issue, which arises when we want to import external proofs into Isabelle.
The below theory compiles in Isabelle 2013 without problems.
The problem is that no matter, how we adjust the imports / code_reflect settings,
we get different errors with the repository version (6a7ee03902c3) when invoking the apply eval statement in the last proof:
importing "~~/src/HOL/Library/Code_Target_Numeral", no code_reflect:
works, but not desired
importing "~~/src/HOL/Library/Code_Target_Numeral", code_reflect mentions nat, but not int (as it worked in 2013):
"Error: Type error in function application.
Function: Checker.checker : Checker.inta -> Checker.proof -> bool
Argument: (Int_of_integer (25 : IntInf.int)) : inta
Reason: Can't unify Checker.inta with inta (Different type constructors)"
importing "~~/src/HOL/Library/Code_Target_Numeral", code_reflect mentions both int and nat:
previous error disappears, but "Abstraction violation: constant Code_Target_Nat.Nat" in last apply eval
importing "~~/src/HOL/Library/Code_Target_Numeral", code_reflect mentions only int, but not nat:
same as before
trying to also load Code_Binary_Nat also did not help.
Any feedback is welcome.
Cheers,
René
theory Test_Import
imports Main
"~~/src/HOL/Library/Code_Char"
(* in repository: "~~/src/HOL/Library/Code_Target_Numeral" *)
(* in 2013: *)
"~~/src/HOL/Library/Code_Integer"
"~~/src/HOL/Library/Code_Natural"
begin
definition parse_digit :: "char => nat" where
"parse_digit c = (
if c = CHR ''0'' then 0 else
if c = CHR ''1'' then 1 else
if c = CHR ''2'' then 2 else
if c = CHR ''3'' then 3 else
if c = CHR ''4'' then 4 else
if c = CHR ''5'' then 5 else
if c = CHR ''6'' then 6 else
if c = CHR ''7'' then 7 else
if c = CHR ''8'' then 8 else 9)"
datatype "proof" = N nat | I int
definition parse_proof :: "string => proof" where
"parse_proof input = (case input of
t # d # _ =>
if t = CHR ''n'' then N (parse_digit d)
else I (of_nat (parse_digit d)))"
definition parse_proof_term :: "string => Code_Evaluation.term" where
"parse_proof_term input == Code_Evaluation.term_of (parse_proof input)"
ML {*
structure Parser =
struct
val parse = String.explode #> @{code parse_proof_term}
end
*}
fun checker :: "int => proof => bool" where
"checker n (N i) = (of_nat i * of_nat i = n)"
| "checker n (I i) = (i * i = n)"
lemma checker_imp_square: "checker n p ⟹ ? x. x * x = n"
by (cases p, auto)
(* precompilation of checker-code, so that it does not need to
be recompiled on every invokation of eval later on,
strangely, in 2013 only nat must be registered as datatype, but not int *)
code_reflect Checker
datatypes (* in repo: int = "_" and *) nat = "_" and "proof" = "_"
functions checker Trueprop
declare checker_def[code del]
setup {*
let
fun import_proof_tac ctxt input i =
let
val thy = Proof_Context.theory_of ctxt
val prf = cterm_of thy (Parser.parse input)
in
rtac @{thm checker_imp_square} i
THEN PRIMITIVE (Drule.instantiate' [] [SOME prf])
end
in
Method.setup @{binding import_proof}
(Scan.lift Parse.string >> (fn input => fn ctxt => SIMPLE_METHOD' (import_proof_tac ctxt input)))
"instantiates a proof via ML, usually, the string would be some file content"
end
*}
lemma "? x :: int. x * x = 25"
apply (import_proof "i5")
apply eval
done
lemma "? x :: int. x * x = 25"
apply (import_proof "n5")
apply eval
(*
On repository version:
Abstraction violation:
constant Code_Target_Nat.Nat
*)
done
end
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