Imported Upstream version 8.5~beta3+dfsg

1 files changed, 13 insertions, 0 deletions

diff --git a/plugins/extraction/ExtrHaskellNatInt.v b/plugins/extraction/ExtrHaskellNatInt.v
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+++ b/plugins/extraction/ExtrHaskellNatInt.v
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+(** Extraction of [nat] into Haskell's [Int] *)
+
+Require Import Arith.
+Require Import ExtrHaskellNatNum.
+
+(**
+ * Disclaimer: trying to obtain efficient certified programs
+ * by extracting [nat] into [Int] is definitively *not* a good idea.
+ * See comments in [ExtrOcamlNatInt.v].
+ *)
+
+Extract Inductive nat => "Prelude.Int" [ "0" "Prelude.succ" ]
+  "(\fO fS n -> if n Prelude.== 0 then fO () else fS (n Prelude.- 1))".