Merge branch 'v8.5' into trunk

1 files changed, 24 insertions, 0 deletions

diff --git a/plugins/extraction/ExtrHaskellZInt.v b/plugins/extraction/ExtrHaskellZInt.v
new file mode 100644
index 0000000000..66690851a7
--- /dev/null
+++ b/plugins/extraction/ExtrHaskellZInt.v
@@ -0,0 +1,24 @@
+(** Extraction of [Z] into Haskell's [Int] *)
+
+Require Import ZArith.
+Require Import ExtrHaskellZNum.
+
+(**
+ * Disclaimer: trying to obtain efficient certified programs
+ * by extracting [Z] into [Int] is definitively *not* a good idea.
+ * See comments in [ExtrOcamlNatInt.v].
+ *)
+
+Extract Inductive positive => "Prelude.Int" [
+  "(\x -> 2 Prelude.* x Prelude.+ 1)"
+  "(\x -> 2 Prelude.* x)"
+  "1" ]
+  "(\fI fO fH n -> if n Prelude.== 1 then fH () else
+                   if Prelude.odd n
+                   then fI (n `Prelude.div` 2)
+                   else fO (n `Prelude.div` 2))".
+
+Extract Inductive Z => "Prelude.Int" [ "0" "(\x -> x)" "Prelude.negate" ]
+  "(\fO fP fN n -> if n Prelude.== 0 then fO () else
+                   if n Prelude.> 0 then fP n else
+                   fN (Prelude.negate n))".