src/HOL/Library/LSC.thy
changeset 41905 e2611bc96022
child 41908 3bd9a21366d2
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/LSC.thy	Fri Mar 11 10:37:35 2011 +0100
@@ -0,0 +1,219 @@
+(* Author: Lukas Bulwahn, TU Muenchen *)
+
+header {* Counterexample generator based on LazySmallCheck *}
+
+theory LSC
+imports Main "~~/src/HOL/Library/Code_Char"
+uses ("~~/src/HOL/Tools/LSC/lazysmallcheck.ML")
+begin
+
+subsection {* Counterexample generator *}
+
+subsubsection {* LSC's deep representation of types of terms *}
+
+datatype type = SumOfProd "type list list"
+
+datatype "term" = Var "code_numeral list" type | Ctr code_numeral "term list"
+
+datatype 'a cons = C type "(term list => 'a) list"
+
+subsubsection {* auxilary functions for LSC *}
+
+definition nth :: "'a list => code_numeral => 'a"
+where
+  "nth xs i = List.nth xs (Code_Numeral.nat_of i)"
+
+lemma [code]:
+  "nth (x # xs) i = (if i = 0 then x else nth xs (i - 1))"
+unfolding nth_def by (cases i) simp
+
+definition error :: "char list => 'a"
+where
+  "error = undefined"
+
+code_const error ("Haskell" "error")
+
+definition toEnum' :: "code_numeral => char"
+where
+  "toEnum' = undefined"
+
+code_const toEnum' ("Haskell" "(toEnum . fromInteger)")
+
+subsubsection {* LSC's basic operations *}
+
+type_synonym 'a series = "code_numeral => 'a cons"
+
+definition empty :: "'a series"
+where
+  "empty d = C (SumOfProd []) []"
+  
+definition cons :: "'a => 'a series"
+where
+  "cons a d = (C (SumOfProd [[]]) [(%_. a)])"
+
+fun conv :: "(term list => 'a) list => term => 'a"
+where
+  "conv cs (Var p _) = error (Char Nibble0 Nibble0 # map toEnum' p)"
+| "conv cs (Ctr i xs) = (nth cs i) xs"
+
+fun nonEmpty :: "type => bool"
+where
+  "nonEmpty (SumOfProd ps) = (\<not> (List.null ps))"
+
+definition "apply" :: "('a => 'b) series => 'a series => 'b series"
+where
+  "apply f a d =
+     (case f d of C (SumOfProd ps) cfs =>
+       case a (d - 1) of C ta cas =>
+       let
+         shallow = (d > 0 \<and> nonEmpty ta);
+         cs = [(%xs'. (case xs' of [] => undefined | x # xs => cf xs (conv cas x))). shallow, cf <- cfs]
+       in C (SumOfProd [ta # p. shallow, p <- ps]) cs)"
+
+definition sum :: "'a series => 'a series => 'a series"
+where
+  "sum a b d =
+    (case a d of C (SumOfProd ssa) ca => 
+      case b d of C (SumOfProd ssb) cb =>
+      C (SumOfProd (ssa @ ssb)) (ca @ cb))"
+
+definition cons0 :: "'a => 'a series"
+where
+  "cons0 f = cons f"
+
+
+subsubsection {* LSC's type class for enumeration *}
+
+class serial =
+  fixes series :: "code_numeral => 'a cons"
+
+definition cons1 :: "('a::serial => 'b) => 'b series"
+where
+  "cons1 f = apply (cons f) series"
+
+definition cons2 :: "('a :: serial => 'b :: serial => 'c) => 'c series"
+where
+  "cons2 f = apply (apply (cons f) series) series"
+  
+instantiation unit :: serial
+begin
+
+definition
+  "series = cons0 ()"
+
+instance ..
+
+end
+
+instantiation bool :: serial
+begin
+
+definition
+  "series = sum (cons0 True) (cons0 False)" 
+
+instance ..
+
+end
+
+instantiation option :: (serial) serial
+begin
+
+definition
+  "series = sum (cons0 None) (cons1 Some)"
+
+instance ..
+
+end
+
+instantiation sum :: (serial, serial) serial
+begin
+
+definition
+  "series = sum (cons1 Inl) (cons1 Inr)"
+
+instance ..
+
+end
+
+instantiation list :: (serial) serial
+begin
+
+function series_list :: "'a list series"
+where
+  "series_list d = sum (cons []) (apply (apply (cons Cons) series) series_list) d"
+by pat_completeness auto
+
+termination sorry
+
+instance ..
+
+end
+
+instantiation nat :: serial
+begin
+
+function series_nat :: "nat series"
+where
+  "series_nat d = sum (cons 0) (apply (cons Suc) series_nat) d"
+by pat_completeness auto
+
+termination sorry
+
+instance ..
+
+end
+
+instantiation Enum.finite_1 :: serial
+begin
+
+definition series_finite_1 :: "Enum.finite_1 series"
+where
+  "series_finite_1 = cons (Enum.finite_1.a\<^isub>1 :: Enum.finite_1)"
+
+instance ..
+
+end
+
+instantiation Enum.finite_2 :: serial
+begin
+
+definition series_finite_2 :: "Enum.finite_2 series"
+where
+  "series_finite_2 = sum (cons (Enum.finite_2.a\<^isub>1 :: Enum.finite_2)) (cons (Enum.finite_2.a\<^isub>2 :: Enum.finite_2))"
+
+instance ..
+
+end
+
+instantiation Enum.finite_3 :: serial
+begin
+
+definition series_finite_3 :: "Enum.finite_3 series"
+where
+  "series_finite_3 = sum (cons (Enum.finite_3.a\<^isub>1 :: Enum.finite_3)) (sum (cons (Enum.finite_3.a\<^isub>2 :: Enum.finite_3)) (cons (Enum.finite_3.a\<^isub>3 :: Enum.finite_3)))"
+
+instance ..
+
+end
+
+subsubsection {* class is_testable *}
+
+text {* The class is_testable ensures that all necessary type instances are generated. *}
+
+class is_testable
+
+instance bool :: is_testable ..
+
+instance "fun" :: ("{term_of, serial}", is_testable) is_testable ..
+
+definition ensure_testable :: "'a :: is_testable => 'a :: is_testable"
+where
+  "ensure_testable f = f"
+
+subsubsection {* Setting up the counterexample generator *}
+  
+use "Tools/LSC/lazysmallcheck.ML"
+
+setup {* Lazysmallcheck.setup *}
+
+end
\ No newline at end of file