1 files changed, 38 insertions, 0 deletions
diff --git a/plugins/extraction/ExtrHaskellString.v b/plugins/extraction/ExtrHaskellString.v
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+(**
+ * Special handling of ascii and strings for extraction to Haskell.
+ *)
+
+Require Import Ascii.
+Require Import String.
+
+(**
+ * At the moment, Coq's extraction has no way to add extra import
+ * statements to the extracted Haskell code.  You will have to
+ * manually add:
+ *
+ *   import qualified Data.Bits
+ *   import qualified Data.Char
+ *)
+
+Extract Inductive ascii => "Prelude.Char"
+  [ "(\b0 b1 b2 b3 b4 b5 b6 b7 -> Data.Char.chr (
+      (if b0 then Data.Bits.shiftL 1 0 else 0) Prelude.+
+      (if b1 then Data.Bits.shiftL 1 1 else 0) Prelude.+
+      (if b2 then Data.Bits.shiftL 1 2 else 0) Prelude.+
+      (if b3 then Data.Bits.shiftL 1 3 else 0) Prelude.+
+      (if b4 then Data.Bits.shiftL 1 4 else 0) Prelude.+
+      (if b5 then Data.Bits.shiftL 1 5 else 0) Prelude.+
+      (if b6 then Data.Bits.shiftL 1 6 else 0) Prelude.+
+      (if b7 then Data.Bits.shiftL 1 7 else 0)))" ]
+  "(\f a -> f (Data.Bits.testBit (Data.Char.ord a) 0)
+              (Data.Bits.testBit (Data.Char.ord a) 1)
+              (Data.Bits.testBit (Data.Char.ord a) 2)
+              (Data.Bits.testBit (Data.Char.ord a) 3)
+              (Data.Bits.testBit (Data.Char.ord a) 4)
+              (Data.Bits.testBit (Data.Char.ord a) 5)
+              (Data.Bits.testBit (Data.Char.ord a) 6)
+              (Data.Bits.testBit (Data.Char.ord a) 7))".
+Extract Inlined Constant Ascii.ascii_dec => "(Prelude.==)".
+
+Extract Inductive string => "Prelude.String" [ "([])" "(:)" ].
+Extract Inlined Constant String.string_dec => "(Prelude.==)".