src/HOL/List.thy
author haftmann
Mon Aug 14 13:46:06 2006 +0200 (2006-08-14)
changeset 20380 14f9f2a1caa6
parent 20355 50aaae6ae4db
child 20401 f01ae74f29f2
permissions -rw-r--r--
simplified code generator setup
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(*  Title:      HOL/List.thy
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    ID:         $Id$
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    Author:     Tobias Nipkow
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*)
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header {* The datatype of finite lists *}
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theory List
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imports PreList FunDef
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begin
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datatype 'a list =
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    Nil    ("[]")
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  | Cons 'a  "'a list"    (infixr "#" 65)
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subsection{*Basic list processing functions*}
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consts
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  "@" :: "'a list => 'a list => 'a list"    (infixr 65)
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  filter:: "('a => bool) => 'a list => 'a list"
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  concat:: "'a list list => 'a list"
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  foldl :: "('b => 'a => 'b) => 'b => 'a list => 'b"
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  foldr :: "('a => 'b => 'b) => 'a list => 'b => 'b"
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  hd:: "'a list => 'a"
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  tl:: "'a list => 'a list"
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  last:: "'a list => 'a"
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  butlast :: "'a list => 'a list"
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  set :: "'a list => 'a set"
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  list_all2 :: "('a => 'b => bool) => 'a list => 'b list => bool"
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  map :: "('a=>'b) => ('a list => 'b list)"
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  nth :: "'a list => nat => 'a"    (infixl "!" 100)
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  list_update :: "'a list => nat => 'a => 'a list"
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  take:: "nat => 'a list => 'a list"
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  drop:: "nat => 'a list => 'a list"
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  takeWhile :: "('a => bool) => 'a list => 'a list"
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  dropWhile :: "('a => bool) => 'a list => 'a list"
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  rev :: "'a list => 'a list"
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  zip :: "'a list => 'b list => ('a * 'b) list"
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  upt :: "nat => nat => nat list" ("(1[_..</_'])")
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  remdups :: "'a list => 'a list"
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  remove1 :: "'a => 'a list => 'a list"
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  null:: "'a list => bool"
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  "distinct":: "'a list => bool"
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  replicate :: "nat => 'a => 'a list"
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  rotate1 :: "'a list \<Rightarrow> 'a list"
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  rotate :: "nat \<Rightarrow> 'a list \<Rightarrow> 'a list"
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  splice :: "'a list \<Rightarrow> 'a list \<Rightarrow> 'a list"
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  sublist :: "'a list => nat set => 'a list"
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(* For efficiency *)
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  mem :: "'a => 'a list => bool"    (infixl 55)
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  list_inter :: "'a list \<Rightarrow> 'a list \<Rightarrow> 'a list"
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  list_ex :: "('a \<Rightarrow> bool) \<Rightarrow> 'a list \<Rightarrow> bool"
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  list_all:: "('a => bool) => ('a list => bool)"
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  itrev :: "'a list \<Rightarrow> 'a list \<Rightarrow> 'a list"
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  filtermap :: "('a \<Rightarrow> 'b option) \<Rightarrow> 'a list \<Rightarrow> 'b list"
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  map_filter :: "('a => 'b) => ('a => bool) => 'a list => 'b list"
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abbreviation
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  upto:: "nat => nat => nat list"    ("(1[_../_])")
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  "[i..j] == [i..<(Suc j)]"
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nonterminals lupdbinds lupdbind
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syntax
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  -- {* list Enumeration *}
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  "@list" :: "args => 'a list"    ("[(_)]")
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  -- {* Special syntax for filter *}
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  "@filter" :: "[pttrn, 'a list, bool] => 'a list"    ("(1[_:_./ _])")
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  -- {* list update *}
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  "_lupdbind":: "['a, 'a] => lupdbind"    ("(2_ :=/ _)")
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  "" :: "lupdbind => lupdbinds"    ("_")
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  "_lupdbinds" :: "[lupdbind, lupdbinds] => lupdbinds"    ("_,/ _")
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  "_LUpdate" :: "['a, lupdbinds] => 'a"    ("_/[(_)]" [900,0] 900)
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translations
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  "[x, xs]" == "x#[xs]"
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  "[x]" == "x#[]"
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  "[x:xs . P]"== "filter (%x. P) xs"
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  "_LUpdate xs (_lupdbinds b bs)"== "_LUpdate (_LUpdate xs b) bs"
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  "xs[i:=x]" == "list_update xs i x"
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syntax (xsymbols)
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  "@filter" :: "[pttrn, 'a list, bool] => 'a list"("(1[_\<in>_ ./ _])")
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syntax (HTML output)
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  "@filter" :: "[pttrn, 'a list, bool] => 'a list"("(1[_\<in>_ ./ _])")
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text {*
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  Function @{text size} is overloaded for all datatypes. Users may
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  refer to the list version as @{text length}. *}
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abbreviation
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  length :: "'a list => nat"
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  "length == size"
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primrec
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  "hd(x#xs) = x"
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primrec
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  "tl([]) = []"
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  "tl(x#xs) = xs"
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primrec
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  "null([]) = True"
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  "null(x#xs) = False"
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primrec
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  "last(x#xs) = (if xs=[] then x else last xs)"
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primrec
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  "butlast []= []"
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  "butlast(x#xs) = (if xs=[] then [] else x#butlast xs)"
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primrec
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  "set [] = {}"
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  "set (x#xs) = insert x (set xs)"
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primrec
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  "map f [] = []"
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  "map f (x#xs) = f(x)#map f xs"
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primrec
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  append_Nil:"[]@ys = ys"
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  append_Cons: "(x#xs)@ys = x#(xs@ys)"
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primrec
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  "rev([]) = []"
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  "rev(x#xs) = rev(xs) @ [x]"
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primrec
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  "filter P [] = []"
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  "filter P (x#xs) = (if P x then x#filter P xs else filter P xs)"
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primrec
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  foldl_Nil:"foldl f a [] = a"
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  foldl_Cons: "foldl f a (x#xs) = foldl f (f a x) xs"
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primrec
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  "foldr f [] a = a"
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  "foldr f (x#xs) a = f x (foldr f xs a)"
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primrec
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  "concat([]) = []"
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  "concat(x#xs) = x @ concat(xs)"
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primrec
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  drop_Nil:"drop n [] = []"
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  drop_Cons: "drop n (x#xs) = (case n of 0 => x#xs | Suc(m) => drop m xs)"
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  -- {*Warning: simpset does not contain this definition, but separate
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       theorems for @{text "n = 0"} and @{text "n = Suc k"} *}
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primrec
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  take_Nil:"take n [] = []"
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  take_Cons: "take n (x#xs) = (case n of 0 => [] | Suc(m) => x # take m xs)"
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  -- {*Warning: simpset does not contain this definition, but separate
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       theorems for @{text "n = 0"} and @{text "n = Suc k"} *}
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primrec
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  nth_Cons:"(x#xs)!n = (case n of 0 => x | (Suc k) => xs!k)"
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  -- {*Warning: simpset does not contain this definition, but separate
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       theorems for @{text "n = 0"} and @{text "n = Suc k"} *}
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primrec
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  "[][i:=v] = []"
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  "(x#xs)[i:=v] = (case i of 0 => v # xs | Suc j => x # xs[j:=v])"
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primrec
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  "takeWhile P [] = []"
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  "takeWhile P (x#xs) = (if P x then x#takeWhile P xs else [])"
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primrec
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  "dropWhile P [] = []"
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  "dropWhile P (x#xs) = (if P x then dropWhile P xs else x#xs)"
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primrec
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  "zip xs [] = []"
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  zip_Cons: "zip xs (y#ys) = (case xs of [] => [] | z#zs => (z,y)#zip zs ys)"
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  -- {*Warning: simpset does not contain this definition, but separate
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       theorems for @{text "xs = []"} and @{text "xs = z # zs"} *}
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primrec
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  upt_0: "[i..<0] = []"
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  upt_Suc: "[i..<(Suc j)] = (if i <= j then [i..<j] @ [j] else [])"
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primrec
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  "distinct [] = True"
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  "distinct (x#xs) = (x ~: set xs \<and> distinct xs)"
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primrec
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  "remdups [] = []"
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  "remdups (x#xs) = (if x : set xs then remdups xs else x # remdups xs)"
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primrec
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  "remove1 x [] = []"
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  "remove1 x (y#xs) = (if x=y then xs else y # remove1 x xs)"
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primrec
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  replicate_0: "replicate 0 x = []"
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  replicate_Suc: "replicate (Suc n) x = x # replicate n x"
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defs
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rotate1_def: "rotate1 xs == (case xs of [] \<Rightarrow> [] | x#xs \<Rightarrow> xs @ [x])"
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rotate_def:  "rotate n == rotate1 ^ n"
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list_all2_def:
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 "list_all2 P xs ys ==
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  length xs = length ys \<and> (\<forall>(x, y) \<in> set (zip xs ys). P x y)"
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sublist_def:
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 "sublist xs A == map fst (filter (%p. snd p : A) (zip xs [0..<size xs]))"
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primrec
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"splice [] ys = ys"
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"splice (x#xs) ys = (if ys=[] then x#xs else x # hd ys # splice xs (tl ys))"
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  -- {*Warning: simpset does not contain the second eqn but a derived one. *}
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primrec
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  "x mem [] = False"
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  "x mem (y#ys) = (if y=x then True else x mem ys)"
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primrec
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 "list_inter [] bs = []"
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 "list_inter (a#as) bs =
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  (if a \<in> set bs then a#(list_inter as bs) else list_inter as bs)"
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primrec
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  "list_all P [] = True"
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  "list_all P (x#xs) = (P(x) \<and> list_all P xs)"
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primrec
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"list_ex P [] = False"
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"list_ex P (x#xs) = (P x \<or> list_ex P xs)"
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primrec
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 "filtermap f [] = []"
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 "filtermap f (x#xs) =
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    (case f x of None \<Rightarrow> filtermap f xs
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     | Some y \<Rightarrow> y # (filtermap f xs))"
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primrec
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  "map_filter f P [] = []"
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  "map_filter f P (x#xs) = (if P x then f x # map_filter f P xs else 
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               map_filter f P xs)"
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primrec
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"itrev [] ys = ys"
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"itrev (x#xs) ys = itrev xs (x#ys)"
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lemma not_Cons_self [simp]: "xs \<noteq> x # xs"
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by (induct xs) auto
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lemmas not_Cons_self2 [simp] = not_Cons_self [symmetric]
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lemma neq_Nil_conv: "(xs \<noteq> []) = (\<exists>y ys. xs = y # ys)"
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by (induct xs) auto
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lemma length_induct:
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"(!!xs. \<forall>ys. length ys < length xs --> P ys ==> P xs) ==> P xs"
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by (rule measure_induct [of length]) iprover
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subsubsection {* @{text null} *}
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lemma null_empty: "null xs = (xs = [])"
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  by (cases xs) simp_all
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lemma empty_null [code inline]:
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  "(xs = []) = null xs"
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using null_empty [symmetric] .
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subsubsection {* @{text length} *}
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text {*
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Needs to come before @{text "@"} because of theorem @{text
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append_eq_append_conv}.
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*}
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lemma length_append [simp]: "length (xs @ ys) = length xs + length ys"
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by (induct xs) auto
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lemma length_map [simp]: "length (map f xs) = length xs"
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by (induct xs) auto
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lemma length_rev [simp]: "length (rev xs) = length xs"
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by (induct xs) auto
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lemma length_tl [simp]: "length (tl xs) = length xs - 1"
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by (cases xs) auto
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lemma length_0_conv [iff]: "(length xs = 0) = (xs = [])"
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by (induct xs) auto
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lemma length_greater_0_conv [iff]: "(0 < length xs) = (xs \<noteq> [])"
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by (induct xs) auto
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lemma length_Suc_conv:
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"(length xs = Suc n) = (\<exists>y ys. xs = y # ys \<and> length ys = n)"
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by (induct xs) auto
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lemma Suc_length_conv:
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"(Suc n = length xs) = (\<exists>y ys. xs = y # ys \<and> length ys = n)"
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apply (induct xs, simp, simp)
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apply blast
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done
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lemma impossible_Cons [rule_format]: 
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  "length xs <= length ys --> xs = x # ys = False"
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apply (induct xs, auto)
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done
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lemma list_induct2[consumes 1]: "\<And>ys.
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 \<lbrakk> length xs = length ys;
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   P [] [];
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   \<And>x xs y ys. \<lbrakk> length xs = length ys; P xs ys \<rbrakk> \<Longrightarrow> P (x#xs) (y#ys) \<rbrakk>
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 \<Longrightarrow> P xs ys"
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apply(induct xs)
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 apply simp
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apply(case_tac ys)
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 apply simp
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apply(simp)
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done
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subsubsection {* @{text "@"} -- append *}
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lemma append_assoc [simp]: "(xs @ ys) @ zs = xs @ (ys @ zs)"
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by (induct xs) auto
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lemma append_Nil2 [simp]: "xs @ [] = xs"
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by (induct xs) auto
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lemma append_is_Nil_conv [iff]: "(xs @ ys = []) = (xs = [] \<and> ys = [])"
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by (induct xs) auto
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lemma Nil_is_append_conv [iff]: "([] = xs @ ys) = (xs = [] \<and> ys = [])"
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by (induct xs) auto
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lemma append_self_conv [iff]: "(xs @ ys = xs) = (ys = [])"
nipkow@13145
   344
by (induct xs) auto
wenzelm@13114
   345
wenzelm@13142
   346
lemma self_append_conv [iff]: "(xs = xs @ ys) = (ys = [])"
nipkow@13145
   347
by (induct xs) auto
wenzelm@13114
   348
berghofe@13883
   349
lemma append_eq_append_conv [simp]:
berghofe@13883
   350
 "!!ys. length xs = length ys \<or> length us = length vs
berghofe@13883
   351
 ==> (xs@us = ys@vs) = (xs=ys \<and> us=vs)"
berghofe@13883
   352
apply (induct xs)
paulson@14208
   353
 apply (case_tac ys, simp, force)
paulson@14208
   354
apply (case_tac ys, force, simp)
nipkow@13145
   355
done
wenzelm@13142
   356
nipkow@14495
   357
lemma append_eq_append_conv2: "!!ys zs ts.
nipkow@14495
   358
 (xs @ ys = zs @ ts) =
nipkow@14495
   359
 (EX us. xs = zs @ us & us @ ys = ts | xs @ us = zs & ys = us@ ts)"
nipkow@14495
   360
apply (induct xs)
nipkow@14495
   361
 apply fastsimp
nipkow@14495
   362
apply(case_tac zs)
nipkow@14495
   363
 apply simp
nipkow@14495
   364
apply fastsimp
nipkow@14495
   365
done
nipkow@14495
   366
wenzelm@13142
   367
lemma same_append_eq [iff]: "(xs @ ys = xs @ zs) = (ys = zs)"
nipkow@13145
   368
by simp
wenzelm@13142
   369
wenzelm@13142
   370
lemma append1_eq_conv [iff]: "(xs @ [x] = ys @ [y]) = (xs = ys \<and> x = y)"
nipkow@13145
   371
by simp
wenzelm@13114
   372
wenzelm@13142
   373
lemma append_same_eq [iff]: "(ys @ xs = zs @ xs) = (ys = zs)"
nipkow@13145
   374
by simp
wenzelm@13114
   375
wenzelm@13142
   376
lemma append_self_conv2 [iff]: "(xs @ ys = ys) = (xs = [])"
nipkow@13145
   377
using append_same_eq [of _ _ "[]"] by auto
nipkow@3507
   378
wenzelm@13142
   379
lemma self_append_conv2 [iff]: "(ys = xs @ ys) = (xs = [])"
nipkow@13145
   380
using append_same_eq [of "[]"] by auto
wenzelm@13114
   381
wenzelm@13142
   382
lemma hd_Cons_tl [simp]: "xs \<noteq> [] ==> hd xs # tl xs = xs"
nipkow@13145
   383
by (induct xs) auto
wenzelm@13114
   384
wenzelm@13142
   385
lemma hd_append: "hd (xs @ ys) = (if xs = [] then hd ys else hd xs)"
nipkow@13145
   386
by (induct xs) auto
wenzelm@13114
   387
wenzelm@13142
   388
lemma hd_append2 [simp]: "xs \<noteq> [] ==> hd (xs @ ys) = hd xs"
nipkow@13145
   389
by (simp add: hd_append split: list.split)
wenzelm@13114
   390
wenzelm@13142
   391
lemma tl_append: "tl (xs @ ys) = (case xs of [] => tl ys | z#zs => zs @ ys)"
nipkow@13145
   392
by (simp split: list.split)
wenzelm@13114
   393
wenzelm@13142
   394
lemma tl_append2 [simp]: "xs \<noteq> [] ==> tl (xs @ ys) = tl xs @ ys"
nipkow@13145
   395
by (simp add: tl_append split: list.split)
wenzelm@13114
   396
wenzelm@13114
   397
nipkow@14300
   398
lemma Cons_eq_append_conv: "x#xs = ys@zs =
nipkow@14300
   399
 (ys = [] & x#xs = zs | (EX ys'. x#ys' = ys & xs = ys'@zs))"
nipkow@14300
   400
by(cases ys) auto
nipkow@14300
   401
nipkow@15281
   402
lemma append_eq_Cons_conv: "(ys@zs = x#xs) =
nipkow@15281
   403
 (ys = [] & zs = x#xs | (EX ys'. ys = x#ys' & ys'@zs = xs))"
nipkow@15281
   404
by(cases ys) auto
nipkow@15281
   405
nipkow@14300
   406
wenzelm@13142
   407
text {* Trivial rules for solving @{text "@"}-equations automatically. *}
wenzelm@13114
   408
wenzelm@13114
   409
lemma eq_Nil_appendI: "xs = ys ==> xs = [] @ ys"
nipkow@13145
   410
by simp
wenzelm@13114
   411
wenzelm@13142
   412
lemma Cons_eq_appendI:
nipkow@13145
   413
"[| x # xs1 = ys; xs = xs1 @ zs |] ==> x # xs = ys @ zs"
nipkow@13145
   414
by (drule sym) simp
wenzelm@13114
   415
wenzelm@13142
   416
lemma append_eq_appendI:
nipkow@13145
   417
"[| xs @ xs1 = zs; ys = xs1 @ us |] ==> xs @ ys = zs @ us"
nipkow@13145
   418
by (drule sym) simp
wenzelm@13114
   419
wenzelm@13114
   420
wenzelm@13142
   421
text {*
nipkow@13145
   422
Simplification procedure for all list equalities.
nipkow@13145
   423
Currently only tries to rearrange @{text "@"} to see if
nipkow@13145
   424
- both lists end in a singleton list,
nipkow@13145
   425
- or both lists end in the same list.
wenzelm@13142
   426
*}
wenzelm@13142
   427
wenzelm@13142
   428
ML_setup {*
nipkow@3507
   429
local
nipkow@3507
   430
wenzelm@13122
   431
val append_assoc = thm "append_assoc";
wenzelm@13122
   432
val append_Nil = thm "append_Nil";
wenzelm@13122
   433
val append_Cons = thm "append_Cons";
wenzelm@13122
   434
val append1_eq_conv = thm "append1_eq_conv";
wenzelm@13122
   435
val append_same_eq = thm "append_same_eq";
wenzelm@13122
   436
wenzelm@13114
   437
fun last (cons as Const("List.list.Cons",_) $ _ $ xs) =
wenzelm@13462
   438
  (case xs of Const("List.list.Nil",_) => cons | _ => last xs)
wenzelm@13462
   439
  | last (Const("List.op @",_) $ _ $ ys) = last ys
wenzelm@13462
   440
  | last t = t;
wenzelm@13114
   441
wenzelm@13114
   442
fun list1 (Const("List.list.Cons",_) $ _ $ Const("List.list.Nil",_)) = true
wenzelm@13462
   443
  | list1 _ = false;
wenzelm@13114
   444
wenzelm@13114
   445
fun butlast ((cons as Const("List.list.Cons",_) $ x) $ xs) =
wenzelm@13462
   446
  (case xs of Const("List.list.Nil",_) => xs | _ => cons $ butlast xs)
wenzelm@13462
   447
  | butlast ((app as Const("List.op @",_) $ xs) $ ys) = app $ butlast ys
wenzelm@13462
   448
  | butlast xs = Const("List.list.Nil",fastype_of xs);
wenzelm@13114
   449
wenzelm@16973
   450
val rearr_ss = HOL_basic_ss addsimps [append_assoc, append_Nil, append_Cons];
wenzelm@16973
   451
wenzelm@20044
   452
fun list_eq ss (F as (eq as Const(_,eqT)) $ lhs $ rhs) =
wenzelm@13462
   453
  let
wenzelm@13462
   454
    val lastl = last lhs and lastr = last rhs;
wenzelm@13462
   455
    fun rearr conv =
wenzelm@13462
   456
      let
wenzelm@13462
   457
        val lhs1 = butlast lhs and rhs1 = butlast rhs;
wenzelm@13462
   458
        val Type(_,listT::_) = eqT
wenzelm@13462
   459
        val appT = [listT,listT] ---> listT
wenzelm@13462
   460
        val app = Const("List.op @",appT)
wenzelm@13462
   461
        val F2 = eq $ (app$lhs1$lastl) $ (app$rhs1$lastr)
wenzelm@13480
   462
        val eq = HOLogic.mk_Trueprop (HOLogic.mk_eq (F,F2));
wenzelm@20044
   463
        val thm = Goal.prove (Simplifier.the_context ss) [] [] eq
wenzelm@17877
   464
          (K (simp_tac (Simplifier.inherit_context ss rearr_ss) 1));
skalberg@15531
   465
      in SOME ((conv RS (thm RS trans)) RS eq_reflection) end;
wenzelm@13114
   466
wenzelm@13462
   467
  in
wenzelm@13462
   468
    if list1 lastl andalso list1 lastr then rearr append1_eq_conv
wenzelm@13462
   469
    else if lastl aconv lastr then rearr append_same_eq
skalberg@15531
   470
    else NONE
wenzelm@13462
   471
  end;
wenzelm@13462
   472
wenzelm@13114
   473
in
wenzelm@13462
   474
wenzelm@13462
   475
val list_eq_simproc =
wenzelm@20044
   476
  Simplifier.simproc (Theory.sign_of (the_context ())) "list_eq" ["(xs::'a list) = ys"] (K list_eq);
wenzelm@13462
   477
wenzelm@13114
   478
end;
wenzelm@13114
   479
wenzelm@13114
   480
Addsimprocs [list_eq_simproc];
wenzelm@13114
   481
*}
wenzelm@13114
   482
wenzelm@13114
   483
nipkow@15392
   484
subsubsection {* @{text map} *}
wenzelm@13114
   485
wenzelm@13142
   486
lemma map_ext: "(!!x. x : set xs --> f x = g x) ==> map f xs = map g xs"
nipkow@13145
   487
by (induct xs) simp_all
wenzelm@13114
   488
wenzelm@13142
   489
lemma map_ident [simp]: "map (\<lambda>x. x) = (\<lambda>xs. xs)"
nipkow@13145
   490
by (rule ext, induct_tac xs) auto
wenzelm@13114
   491
wenzelm@13142
   492
lemma map_append [simp]: "map f (xs @ ys) = map f xs @ map f ys"
nipkow@13145
   493
by (induct xs) auto
wenzelm@13114
   494
wenzelm@13142
   495
lemma map_compose: "map (f o g) xs = map f (map g xs)"
nipkow@13145
   496
by (induct xs) (auto simp add: o_def)
wenzelm@13114
   497
wenzelm@13142
   498
lemma rev_map: "rev (map f xs) = map f (rev xs)"
nipkow@13145
   499
by (induct xs) auto
wenzelm@13114
   500
nipkow@13737
   501
lemma map_eq_conv[simp]: "(map f xs = map g xs) = (!x : set xs. f x = g x)"
nipkow@13737
   502
by (induct xs) auto
nipkow@13737
   503
krauss@19770
   504
lemma map_cong [fundef_cong, recdef_cong]:
nipkow@13145
   505
"xs = ys ==> (!!x. x : set ys ==> f x = g x) ==> map f xs = map g ys"
nipkow@13145
   506
-- {* a congruence rule for @{text map} *}
nipkow@13737
   507
by simp
wenzelm@13114
   508
wenzelm@13142
   509
lemma map_is_Nil_conv [iff]: "(map f xs = []) = (xs = [])"
nipkow@13145
   510
by (cases xs) auto
wenzelm@13114
   511
wenzelm@13142
   512
lemma Nil_is_map_conv [iff]: "([] = map f xs) = (xs = [])"
nipkow@13145
   513
by (cases xs) auto
wenzelm@13114
   514
paulson@18447
   515
lemma map_eq_Cons_conv:
nipkow@14025
   516
 "(map f xs = y#ys) = (\<exists>z zs. xs = z#zs \<and> f z = y \<and> map f zs = ys)"
nipkow@13145
   517
by (cases xs) auto
wenzelm@13114
   518
paulson@18447
   519
lemma Cons_eq_map_conv:
nipkow@14025
   520
 "(x#xs = map f ys) = (\<exists>z zs. ys = z#zs \<and> x = f z \<and> xs = map f zs)"
nipkow@14025
   521
by (cases ys) auto
nipkow@14025
   522
paulson@18447
   523
lemmas map_eq_Cons_D = map_eq_Cons_conv [THEN iffD1]
paulson@18447
   524
lemmas Cons_eq_map_D = Cons_eq_map_conv [THEN iffD1]
paulson@18447
   525
declare map_eq_Cons_D [dest!]  Cons_eq_map_D [dest!]
paulson@18447
   526
nipkow@14111
   527
lemma ex_map_conv:
nipkow@14111
   528
  "(EX xs. ys = map f xs) = (ALL y : set ys. EX x. y = f x)"
paulson@18447
   529
by(induct ys, auto simp add: Cons_eq_map_conv)
nipkow@14111
   530
nipkow@15110
   531
lemma map_eq_imp_length_eq:
nipkow@15110
   532
  "!!xs. map f xs = map f ys ==> length xs = length ys"
nipkow@15110
   533
apply (induct ys)
nipkow@15110
   534
 apply simp
nipkow@15110
   535
apply(simp (no_asm_use))
nipkow@15110
   536
apply clarify
nipkow@15110
   537
apply(simp (no_asm_use))
nipkow@15110
   538
apply fast
nipkow@15110
   539
done
nipkow@15110
   540
nipkow@15110
   541
lemma map_inj_on:
nipkow@15110
   542
 "[| map f xs = map f ys; inj_on f (set xs Un set ys) |]
nipkow@15110
   543
  ==> xs = ys"
nipkow@15110
   544
apply(frule map_eq_imp_length_eq)
nipkow@15110
   545
apply(rotate_tac -1)
nipkow@15110
   546
apply(induct rule:list_induct2)
nipkow@15110
   547
 apply simp
nipkow@15110
   548
apply(simp)
nipkow@15110
   549
apply (blast intro:sym)
nipkow@15110
   550
done
nipkow@15110
   551
nipkow@15110
   552
lemma inj_on_map_eq_map:
nipkow@15110
   553
 "inj_on f (set xs Un set ys) \<Longrightarrow> (map f xs = map f ys) = (xs = ys)"
nipkow@15110
   554
by(blast dest:map_inj_on)
nipkow@15110
   555
wenzelm@13114
   556
lemma map_injective:
nipkow@14338
   557
 "!!xs. map f xs = map f ys ==> inj f ==> xs = ys"
nipkow@14338
   558
by (induct ys) (auto dest!:injD)
wenzelm@13114
   559
nipkow@14339
   560
lemma inj_map_eq_map[simp]: "inj f \<Longrightarrow> (map f xs = map f ys) = (xs = ys)"
nipkow@14339
   561
by(blast dest:map_injective)
nipkow@14339
   562
wenzelm@13114
   563
lemma inj_mapI: "inj f ==> inj (map f)"
nipkow@17589
   564
by (iprover dest: map_injective injD intro: inj_onI)
wenzelm@13114
   565
wenzelm@13114
   566
lemma inj_mapD: "inj (map f) ==> inj f"
paulson@14208
   567
apply (unfold inj_on_def, clarify)
nipkow@13145
   568
apply (erule_tac x = "[x]" in ballE)
paulson@14208
   569
 apply (erule_tac x = "[y]" in ballE, simp, blast)
nipkow@13145
   570
apply blast
nipkow@13145
   571
done
wenzelm@13114
   572
nipkow@14339
   573
lemma inj_map[iff]: "inj (map f) = inj f"
nipkow@13145
   574
by (blast dest: inj_mapD intro: inj_mapI)
wenzelm@13114
   575
nipkow@15303
   576
lemma inj_on_mapI: "inj_on f (\<Union>(set ` A)) \<Longrightarrow> inj_on (map f) A"
nipkow@15303
   577
apply(rule inj_onI)
nipkow@15303
   578
apply(erule map_inj_on)
nipkow@15303
   579
apply(blast intro:inj_onI dest:inj_onD)
nipkow@15303
   580
done
nipkow@15303
   581
kleing@14343
   582
lemma map_idI: "(\<And>x. x \<in> set xs \<Longrightarrow> f x = x) \<Longrightarrow> map f xs = xs"
kleing@14343
   583
by (induct xs, auto)
wenzelm@13114
   584
nipkow@14402
   585
lemma map_fun_upd [simp]: "y \<notin> set xs \<Longrightarrow> map (f(y:=v)) xs = map f xs"
nipkow@14402
   586
by (induct xs) auto
nipkow@14402
   587
nipkow@15110
   588
lemma map_fst_zip[simp]:
nipkow@15110
   589
  "length xs = length ys \<Longrightarrow> map fst (zip xs ys) = xs"
nipkow@15110
   590
by (induct rule:list_induct2, simp_all)
nipkow@15110
   591
nipkow@15110
   592
lemma map_snd_zip[simp]:
nipkow@15110
   593
  "length xs = length ys \<Longrightarrow> map snd (zip xs ys) = ys"
nipkow@15110
   594
by (induct rule:list_induct2, simp_all)
nipkow@15110
   595
nipkow@15110
   596
nipkow@15392
   597
subsubsection {* @{text rev} *}
wenzelm@13114
   598
wenzelm@13142
   599
lemma rev_append [simp]: "rev (xs @ ys) = rev ys @ rev xs"
nipkow@13145
   600
by (induct xs) auto
wenzelm@13114
   601
wenzelm@13142
   602
lemma rev_rev_ident [simp]: "rev (rev xs) = xs"
nipkow@13145
   603
by (induct xs) auto
wenzelm@13114
   604
kleing@15870
   605
lemma rev_swap: "(rev xs = ys) = (xs = rev ys)"
kleing@15870
   606
by auto
kleing@15870
   607
wenzelm@13142
   608
lemma rev_is_Nil_conv [iff]: "(rev xs = []) = (xs = [])"
nipkow@13145
   609
by (induct xs) auto
wenzelm@13114
   610
wenzelm@13142
   611
lemma Nil_is_rev_conv [iff]: "([] = rev xs) = (xs = [])"
nipkow@13145
   612
by (induct xs) auto
wenzelm@13114
   613
kleing@15870
   614
lemma rev_singleton_conv [simp]: "(rev xs = [x]) = (xs = [x])"
kleing@15870
   615
by (cases xs) auto
kleing@15870
   616
kleing@15870
   617
lemma singleton_rev_conv [simp]: "([x] = rev xs) = (xs = [x])"
kleing@15870
   618
by (cases xs) auto
kleing@15870
   619
wenzelm@13142
   620
lemma rev_is_rev_conv [iff]: "!!ys. (rev xs = rev ys) = (xs = ys)"
paulson@14208
   621
apply (induct xs, force)
paulson@14208
   622
apply (case_tac ys, simp, force)
nipkow@13145
   623
done
wenzelm@13114
   624
nipkow@15439
   625
lemma inj_on_rev[iff]: "inj_on rev A"
nipkow@15439
   626
by(simp add:inj_on_def)
nipkow@15439
   627
wenzelm@13366
   628
lemma rev_induct [case_names Nil snoc]:
wenzelm@13366
   629
  "[| P []; !!x xs. P xs ==> P (xs @ [x]) |] ==> P xs"
berghofe@15489
   630
apply(simplesubst rev_rev_ident[symmetric])
nipkow@13145
   631
apply(rule_tac list = "rev xs" in list.induct, simp_all)
nipkow@13145
   632
done
wenzelm@13114
   633
nipkow@13145
   634
ML {* val rev_induct_tac = induct_thm_tac (thm "rev_induct") *}-- "compatibility"
wenzelm@13114
   635
wenzelm@13366
   636
lemma rev_exhaust [case_names Nil snoc]:
wenzelm@13366
   637
  "(xs = [] ==> P) ==>(!!ys y. xs = ys @ [y] ==> P) ==> P"
nipkow@13145
   638
by (induct xs rule: rev_induct) auto
wenzelm@13114
   639
wenzelm@13366
   640
lemmas rev_cases = rev_exhaust
wenzelm@13366
   641
nipkow@18423
   642
lemma rev_eq_Cons_iff[iff]: "(rev xs = y#ys) = (xs = rev ys @ [y])"
nipkow@18423
   643
by(rule rev_cases[of xs]) auto
nipkow@18423
   644
wenzelm@13114
   645
nipkow@15392
   646
subsubsection {* @{text set} *}
wenzelm@13114
   647
wenzelm@13142
   648
lemma finite_set [iff]: "finite (set xs)"
nipkow@13145
   649
by (induct xs) auto
wenzelm@13114
   650
wenzelm@13142
   651
lemma set_append [simp]: "set (xs @ ys) = (set xs \<union> set ys)"
nipkow@13145
   652
by (induct xs) auto
wenzelm@13114
   653
nipkow@17830
   654
lemma hd_in_set[simp]: "xs \<noteq> [] \<Longrightarrow> hd xs : set xs"
nipkow@17830
   655
by(cases xs) auto
oheimb@14099
   656
wenzelm@13142
   657
lemma set_subset_Cons: "set xs \<subseteq> set (x # xs)"
nipkow@13145
   658
by auto
wenzelm@13114
   659
oheimb@14099
   660
lemma set_ConsD: "y \<in> set (x # xs) \<Longrightarrow> y=x \<or> y \<in> set xs" 
oheimb@14099
   661
by auto
oheimb@14099
   662
wenzelm@13142
   663
lemma set_empty [iff]: "(set xs = {}) = (xs = [])"
nipkow@13145
   664
by (induct xs) auto
wenzelm@13114
   665
nipkow@15245
   666
lemma set_empty2[iff]: "({} = set xs) = (xs = [])"
nipkow@15245
   667
by(induct xs) auto
nipkow@15245
   668
wenzelm@13142
   669
lemma set_rev [simp]: "set (rev xs) = set xs"
nipkow@13145
   670
by (induct xs) auto
wenzelm@13114
   671
wenzelm@13142
   672
lemma set_map [simp]: "set (map f xs) = f`(set xs)"
nipkow@13145
   673
by (induct xs) auto
wenzelm@13114
   674
wenzelm@13142
   675
lemma set_filter [simp]: "set (filter P xs) = {x. x : set xs \<and> P x}"
nipkow@13145
   676
by (induct xs) auto
wenzelm@13114
   677
nipkow@15425
   678
lemma set_upt [simp]: "set[i..<j] = {k. i \<le> k \<and> k < j}"
paulson@14208
   679
apply (induct j, simp_all)
paulson@14208
   680
apply (erule ssubst, auto)
nipkow@13145
   681
done
wenzelm@13114
   682
wenzelm@13142
   683
lemma in_set_conv_decomp: "(x : set xs) = (\<exists>ys zs. xs = ys @ x # zs)"
paulson@15113
   684
proof (induct xs)
paulson@15113
   685
  case Nil show ?case by simp
paulson@15113
   686
  case (Cons a xs)
paulson@15113
   687
  show ?case
paulson@15113
   688
  proof 
paulson@15113
   689
    assume "x \<in> set (a # xs)"
paulson@15113
   690
    with prems show "\<exists>ys zs. a # xs = ys @ x # zs"
paulson@15113
   691
      by (simp, blast intro: Cons_eq_appendI)
paulson@15113
   692
  next
paulson@15113
   693
    assume "\<exists>ys zs. a # xs = ys @ x # zs"
paulson@15113
   694
    then obtain ys zs where eq: "a # xs = ys @ x # zs" by blast
paulson@15113
   695
    show "x \<in> set (a # xs)" 
paulson@15113
   696
      by (cases ys, auto simp add: eq)
paulson@15113
   697
  qed
paulson@15113
   698
qed
wenzelm@13142
   699
nipkow@18049
   700
lemma in_set_conv_decomp_first:
nipkow@18049
   701
 "(x : set xs) = (\<exists>ys zs. xs = ys @ x # zs \<and> x \<notin> set ys)"
nipkow@18049
   702
proof (induct xs)
nipkow@18049
   703
  case Nil show ?case by simp
nipkow@18049
   704
next
nipkow@18049
   705
  case (Cons a xs)
nipkow@18049
   706
  show ?case
nipkow@18049
   707
  proof cases
nipkow@18049
   708
    assume "x = a" thus ?case using Cons by force
nipkow@18049
   709
  next
nipkow@18049
   710
    assume "x \<noteq> a"
nipkow@18049
   711
    show ?case
nipkow@18049
   712
    proof
nipkow@18049
   713
      assume "x \<in> set (a # xs)"
nipkow@18049
   714
      from prems show "\<exists>ys zs. a # xs = ys @ x # zs \<and> x \<notin> set ys"
nipkow@18049
   715
	by(fastsimp intro!: Cons_eq_appendI)
nipkow@18049
   716
    next
nipkow@18049
   717
      assume "\<exists>ys zs. a # xs = ys @ x # zs \<and> x \<notin> set ys"
nipkow@18049
   718
      then obtain ys zs where eq: "a # xs = ys @ x # zs" by blast
nipkow@18049
   719
      show "x \<in> set (a # xs)" by (cases ys, auto simp add: eq)
nipkow@18049
   720
    qed
nipkow@18049
   721
  qed
nipkow@18049
   722
qed
nipkow@18049
   723
nipkow@18049
   724
lemmas split_list       = in_set_conv_decomp[THEN iffD1, standard]
nipkow@18049
   725
lemmas split_list_first = in_set_conv_decomp_first[THEN iffD1, standard]
nipkow@18049
   726
nipkow@18049
   727
paulson@13508
   728
lemma finite_list: "finite A ==> EX l. set l = A"
paulson@13508
   729
apply (erule finite_induct, auto)
paulson@13508
   730
apply (rule_tac x="x#l" in exI, auto)
paulson@13508
   731
done
paulson@13508
   732
kleing@14388
   733
lemma card_length: "card (set xs) \<le> length xs"
kleing@14388
   734
by (induct xs) (auto simp add: card_insert_if)
wenzelm@13114
   735
paulson@15168
   736
nipkow@15392
   737
subsubsection {* @{text filter} *}
wenzelm@13114
   738
wenzelm@13142
   739
lemma filter_append [simp]: "filter P (xs @ ys) = filter P xs @ filter P ys"
nipkow@13145
   740
by (induct xs) auto
wenzelm@13114
   741
nipkow@15305
   742
lemma rev_filter: "rev (filter P xs) = filter P (rev xs)"
nipkow@15305
   743
by (induct xs) simp_all
nipkow@15305
   744
wenzelm@13142
   745
lemma filter_filter [simp]: "filter P (filter Q xs) = filter (\<lambda>x. Q x \<and> P x) xs"
nipkow@13145
   746
by (induct xs) auto
wenzelm@13114
   747
nipkow@16998
   748
lemma length_filter_le [simp]: "length (filter P xs) \<le> length xs"
nipkow@16998
   749
by (induct xs) (auto simp add: le_SucI)
nipkow@16998
   750
nipkow@18423
   751
lemma sum_length_filter_compl:
nipkow@18423
   752
  "length(filter P xs) + length(filter (%x. ~P x) xs) = length xs"
nipkow@18423
   753
by(induct xs) simp_all
nipkow@18423
   754
wenzelm@13142
   755
lemma filter_True [simp]: "\<forall>x \<in> set xs. P x ==> filter P xs = xs"
nipkow@13145
   756
by (induct xs) auto
wenzelm@13114
   757
wenzelm@13142
   758
lemma filter_False [simp]: "\<forall>x \<in> set xs. \<not> P x ==> filter P xs = []"
nipkow@13145
   759
by (induct xs) auto
wenzelm@13114
   760
nipkow@16998
   761
lemma filter_empty_conv: "(filter P xs = []) = (\<forall>x\<in>set xs. \<not> P x)" 
nipkow@16998
   762
  by (induct xs) simp_all
nipkow@16998
   763
nipkow@16998
   764
lemma filter_id_conv: "(filter P xs = xs) = (\<forall>x\<in>set xs. P x)"
nipkow@16998
   765
apply (induct xs)
nipkow@16998
   766
 apply auto
nipkow@16998
   767
apply(cut_tac P=P and xs=xs in length_filter_le)
nipkow@16998
   768
apply simp
nipkow@16998
   769
done
wenzelm@13114
   770
nipkow@16965
   771
lemma filter_map:
nipkow@16965
   772
  "filter P (map f xs) = map f (filter (P o f) xs)"
nipkow@16965
   773
by (induct xs) simp_all
nipkow@16965
   774
nipkow@16965
   775
lemma length_filter_map[simp]:
nipkow@16965
   776
  "length (filter P (map f xs)) = length(filter (P o f) xs)"
nipkow@16965
   777
by (simp add:filter_map)
nipkow@16965
   778
wenzelm@13142
   779
lemma filter_is_subset [simp]: "set (filter P xs) \<le> set xs"
nipkow@13145
   780
by auto
wenzelm@13114
   781
nipkow@15246
   782
lemma length_filter_less:
nipkow@15246
   783
  "\<lbrakk> x : set xs; ~ P x \<rbrakk> \<Longrightarrow> length(filter P xs) < length xs"
nipkow@15246
   784
proof (induct xs)
nipkow@15246
   785
  case Nil thus ?case by simp
nipkow@15246
   786
next
nipkow@15246
   787
  case (Cons x xs) thus ?case
nipkow@15246
   788
    apply (auto split:split_if_asm)
nipkow@15246
   789
    using length_filter_le[of P xs] apply arith
nipkow@15246
   790
  done
nipkow@15246
   791
qed
wenzelm@13114
   792
nipkow@15281
   793
lemma length_filter_conv_card:
nipkow@15281
   794
 "length(filter p xs) = card{i. i < length xs & p(xs!i)}"
nipkow@15281
   795
proof (induct xs)
nipkow@15281
   796
  case Nil thus ?case by simp
nipkow@15281
   797
next
nipkow@15281
   798
  case (Cons x xs)
nipkow@15281
   799
  let ?S = "{i. i < length xs & p(xs!i)}"
nipkow@15281
   800
  have fin: "finite ?S" by(fast intro: bounded_nat_set_is_finite)
nipkow@15281
   801
  show ?case (is "?l = card ?S'")
nipkow@15281
   802
  proof (cases)
nipkow@15281
   803
    assume "p x"
nipkow@15281
   804
    hence eq: "?S' = insert 0 (Suc ` ?S)"
nipkow@15281
   805
      by(auto simp add: nth_Cons image_def split:nat.split elim:lessE)
nipkow@15281
   806
    have "length (filter p (x # xs)) = Suc(card ?S)"
nipkow@15281
   807
      using Cons by simp
nipkow@15281
   808
    also have "\<dots> = Suc(card(Suc ` ?S))" using fin
nipkow@15281
   809
      by (simp add: card_image inj_Suc)
nipkow@15281
   810
    also have "\<dots> = card ?S'" using eq fin
nipkow@15281
   811
      by (simp add:card_insert_if) (simp add:image_def)
nipkow@15281
   812
    finally show ?thesis .
nipkow@15281
   813
  next
nipkow@15281
   814
    assume "\<not> p x"
nipkow@15281
   815
    hence eq: "?S' = Suc ` ?S"
nipkow@15281
   816
      by(auto simp add: nth_Cons image_def split:nat.split elim:lessE)
nipkow@15281
   817
    have "length (filter p (x # xs)) = card ?S"
nipkow@15281
   818
      using Cons by simp
nipkow@15281
   819
    also have "\<dots> = card(Suc ` ?S)" using fin
nipkow@15281
   820
      by (simp add: card_image inj_Suc)
nipkow@15281
   821
    also have "\<dots> = card ?S'" using eq fin
nipkow@15281
   822
      by (simp add:card_insert_if)
nipkow@15281
   823
    finally show ?thesis .
nipkow@15281
   824
  qed
nipkow@15281
   825
qed
nipkow@15281
   826
nipkow@17629
   827
lemma Cons_eq_filterD:
nipkow@17629
   828
 "x#xs = filter P ys \<Longrightarrow>
nipkow@17629
   829
  \<exists>us vs. ys = us @ x # vs \<and> (\<forall>u\<in>set us. \<not> P u) \<and> P x \<and> xs = filter P vs"
wenzelm@19585
   830
  (is "_ \<Longrightarrow> \<exists>us vs. ?P ys us vs")
nipkow@17629
   831
proof(induct ys)
nipkow@17629
   832
  case Nil thus ?case by simp
nipkow@17629
   833
next
nipkow@17629
   834
  case (Cons y ys)
nipkow@17629
   835
  show ?case (is "\<exists>x. ?Q x")
nipkow@17629
   836
  proof cases
nipkow@17629
   837
    assume Py: "P y"
nipkow@17629
   838
    show ?thesis
nipkow@17629
   839
    proof cases
nipkow@17629
   840
      assume xy: "x = y"
nipkow@17629
   841
      show ?thesis
nipkow@17629
   842
      proof from Py xy Cons(2) show "?Q []" by simp qed
nipkow@17629
   843
    next
nipkow@17629
   844
      assume "x \<noteq> y" with Py Cons(2) show ?thesis by simp
nipkow@17629
   845
    qed
nipkow@17629
   846
  next
nipkow@17629
   847
    assume Py: "\<not> P y"
nipkow@17629
   848
    with Cons obtain us vs where 1 : "?P (y#ys) (y#us) vs" by fastsimp
nipkow@17629
   849
    show ?thesis (is "? us. ?Q us")
nipkow@17629
   850
    proof show "?Q (y#us)" using 1 by simp qed
nipkow@17629
   851
  qed
nipkow@17629
   852
qed
nipkow@17629
   853
nipkow@17629
   854
lemma filter_eq_ConsD:
nipkow@17629
   855
 "filter P ys = x#xs \<Longrightarrow>
nipkow@17629
   856
  \<exists>us vs. ys = us @ x # vs \<and> (\<forall>u\<in>set us. \<not> P u) \<and> P x \<and> xs = filter P vs"
nipkow@17629
   857
by(rule Cons_eq_filterD) simp
nipkow@17629
   858
nipkow@17629
   859
lemma filter_eq_Cons_iff:
nipkow@17629
   860
 "(filter P ys = x#xs) =
nipkow@17629
   861
  (\<exists>us vs. ys = us @ x # vs \<and> (\<forall>u\<in>set us. \<not> P u) \<and> P x \<and> xs = filter P vs)"
nipkow@17629
   862
by(auto dest:filter_eq_ConsD)
nipkow@17629
   863
nipkow@17629
   864
lemma Cons_eq_filter_iff:
nipkow@17629
   865
 "(x#xs = filter P ys) =
nipkow@17629
   866
  (\<exists>us vs. ys = us @ x # vs \<and> (\<forall>u\<in>set us. \<not> P u) \<and> P x \<and> xs = filter P vs)"
nipkow@17629
   867
by(auto dest:Cons_eq_filterD)
nipkow@17629
   868
krauss@19770
   869
lemma filter_cong[fundef_cong, recdef_cong]:
nipkow@17501
   870
 "xs = ys \<Longrightarrow> (\<And>x. x \<in> set ys \<Longrightarrow> P x = Q x) \<Longrightarrow> filter P xs = filter Q ys"
nipkow@17501
   871
apply simp
nipkow@17501
   872
apply(erule thin_rl)
nipkow@17501
   873
by (induct ys) simp_all
nipkow@17501
   874
nipkow@15281
   875
nipkow@15392
   876
subsubsection {* @{text concat} *}
wenzelm@13114
   877
wenzelm@13142
   878
lemma concat_append [simp]: "concat (xs @ ys) = concat xs @ concat ys"
nipkow@13145
   879
by (induct xs) auto
wenzelm@13114
   880
paulson@18447
   881
lemma concat_eq_Nil_conv [simp]: "(concat xss = []) = (\<forall>xs \<in> set xss. xs = [])"
nipkow@13145
   882
by (induct xss) auto
wenzelm@13114
   883
paulson@18447
   884
lemma Nil_eq_concat_conv [simp]: "([] = concat xss) = (\<forall>xs \<in> set xss. xs = [])"
nipkow@13145
   885
by (induct xss) auto
wenzelm@13114
   886
wenzelm@13142
   887
lemma set_concat [simp]: "set (concat xs) = \<Union>(set ` set xs)"
nipkow@13145
   888
by (induct xs) auto
wenzelm@13114
   889
wenzelm@13142
   890
lemma map_concat: "map f (concat xs) = concat (map (map f) xs)"
nipkow@13145
   891
by (induct xs) auto
wenzelm@13114
   892
wenzelm@13142
   893
lemma filter_concat: "filter p (concat xs) = concat (map (filter p) xs)"
nipkow@13145
   894
by (induct xs) auto
wenzelm@13114
   895
wenzelm@13142
   896
lemma rev_concat: "rev (concat xs) = concat (map rev (rev xs))"
nipkow@13145
   897
by (induct xs) auto
wenzelm@13114
   898
wenzelm@13114
   899
nipkow@15392
   900
subsubsection {* @{text nth} *}
wenzelm@13114
   901
wenzelm@13142
   902
lemma nth_Cons_0 [simp]: "(x # xs)!0 = x"
nipkow@13145
   903
by auto
wenzelm@13114
   904
wenzelm@13142
   905
lemma nth_Cons_Suc [simp]: "(x # xs)!(Suc n) = xs!n"
nipkow@13145
   906
by auto
wenzelm@13114
   907
wenzelm@13142
   908
declare nth.simps [simp del]
wenzelm@13114
   909
wenzelm@13114
   910
lemma nth_append:
nipkow@13145
   911
"!!n. (xs @ ys)!n = (if n < length xs then xs!n else ys!(n - length xs))"
paulson@14208
   912
apply (induct "xs", simp)
paulson@14208
   913
apply (case_tac n, auto)
nipkow@13145
   914
done
wenzelm@13114
   915
nipkow@14402
   916
lemma nth_append_length [simp]: "(xs @ x # ys) ! length xs = x"
nipkow@14402
   917
by (induct "xs") auto
nipkow@14402
   918
nipkow@14402
   919
lemma nth_append_length_plus[simp]: "(xs @ ys) ! (length xs + n) = ys ! n"
nipkow@14402
   920
by (induct "xs") auto
nipkow@14402
   921
wenzelm@13142
   922
lemma nth_map [simp]: "!!n. n < length xs ==> (map f xs)!n = f(xs!n)"
paulson@14208
   923
apply (induct xs, simp)
paulson@14208
   924
apply (case_tac n, auto)
nipkow@13145
   925
done
wenzelm@13114
   926
nipkow@18423
   927
lemma hd_conv_nth: "xs \<noteq> [] \<Longrightarrow> hd xs = xs!0"
nipkow@18423
   928
by(cases xs) simp_all
nipkow@18423
   929
nipkow@18049
   930
nipkow@18049
   931
lemma list_eq_iff_nth_eq:
nipkow@18049
   932
 "!!ys. (xs = ys) = (length xs = length ys \<and> (ALL i<length xs. xs!i = ys!i))"
nipkow@18049
   933
apply(induct xs)
nipkow@18049
   934
 apply simp apply blast
nipkow@18049
   935
apply(case_tac ys)
nipkow@18049
   936
 apply simp
nipkow@18049
   937
apply(simp add:nth_Cons split:nat.split)apply blast
nipkow@18049
   938
done
nipkow@18049
   939
wenzelm@13142
   940
lemma set_conv_nth: "set xs = {xs!i | i. i < length xs}"
paulson@15251
   941
apply (induct xs, simp, simp)
nipkow@13145
   942
apply safe
paulson@14208
   943
apply (rule_tac x = 0 in exI, simp)
paulson@14208
   944
 apply (rule_tac x = "Suc i" in exI, simp)
paulson@14208
   945
apply (case_tac i, simp)
nipkow@13145
   946
apply (rename_tac j)
paulson@14208
   947
apply (rule_tac x = j in exI, simp)
nipkow@13145
   948
done
wenzelm@13114
   949
nipkow@17501
   950
lemma in_set_conv_nth: "(x \<in> set xs) = (\<exists>i < length xs. xs!i = x)"
nipkow@17501
   951
by(auto simp:set_conv_nth)
nipkow@17501
   952
nipkow@13145
   953
lemma list_ball_nth: "[| n < length xs; !x : set xs. P x|] ==> P(xs!n)"
nipkow@13145
   954
by (auto simp add: set_conv_nth)
wenzelm@13114
   955
wenzelm@13142
   956
lemma nth_mem [simp]: "n < length xs ==> xs!n : set xs"
nipkow@13145
   957
by (auto simp add: set_conv_nth)
wenzelm@13114
   958
wenzelm@13114
   959
lemma all_nth_imp_all_set:
nipkow@13145
   960
"[| !i < length xs. P(xs!i); x : set xs|] ==> P x"
nipkow@13145
   961
by (auto simp add: set_conv_nth)
wenzelm@13114
   962
wenzelm@13114
   963
lemma all_set_conv_all_nth:
nipkow@13145
   964
"(\<forall>x \<in> set xs. P x) = (\<forall>i. i < length xs --> P (xs ! i))"
nipkow@13145
   965
by (auto simp add: set_conv_nth)
wenzelm@13114
   966
wenzelm@13114
   967
nipkow@15392
   968
subsubsection {* @{text list_update} *}
wenzelm@13114
   969
wenzelm@13142
   970
lemma length_list_update [simp]: "!!i. length(xs[i:=x]) = length xs"
nipkow@13145
   971
by (induct xs) (auto split: nat.split)
wenzelm@13114
   972
wenzelm@13114
   973
lemma nth_list_update:
nipkow@13145
   974
"!!i j. i < length xs==> (xs[i:=x])!j = (if i = j then x else xs!j)"
nipkow@13145
   975
by (induct xs) (auto simp add: nth_Cons split: nat.split)
wenzelm@13114
   976
wenzelm@13142
   977
lemma nth_list_update_eq [simp]: "i < length xs ==> (xs[i:=x])!i = x"
nipkow@13145
   978
by (simp add: nth_list_update)
wenzelm@13114
   979
wenzelm@13142
   980
lemma nth_list_update_neq [simp]: "!!i j. i \<noteq> j ==> xs[i:=x]!j = xs!j"
nipkow@13145
   981
by (induct xs) (auto simp add: nth_Cons split: nat.split)
wenzelm@13114
   982
wenzelm@13142
   983
lemma list_update_overwrite [simp]:
nipkow@13145
   984
"!!i. i < size xs ==> xs[i:=x, i:=y] = xs[i:=y]"
nipkow@13145
   985
by (induct xs) (auto split: nat.split)
wenzelm@13114
   986
nipkow@14402
   987
lemma list_update_id[simp]: "!!i. i < length xs ==> xs[i := xs!i] = xs"
paulson@14208
   988
apply (induct xs, simp)
nipkow@14187
   989
apply(simp split:nat.splits)
nipkow@14187
   990
done
nipkow@14187
   991
nipkow@17501
   992
lemma list_update_beyond[simp]: "\<And>i. length xs \<le> i \<Longrightarrow> xs[i:=x] = xs"
nipkow@17501
   993
apply (induct xs)
nipkow@17501
   994
 apply simp
nipkow@17501
   995
apply (case_tac i)
nipkow@17501
   996
apply simp_all
nipkow@17501
   997
done
nipkow@17501
   998
wenzelm@13114
   999
lemma list_update_same_conv:
nipkow@13145
  1000
"!!i. i < length xs ==> (xs[i := x] = xs) = (xs!i = x)"
nipkow@13145
  1001
by (induct xs) (auto split: nat.split)
wenzelm@13114
  1002
nipkow@14187
  1003
lemma list_update_append1:
nipkow@14187
  1004
 "!!i. i < size xs \<Longrightarrow> (xs @ ys)[i:=x] = xs[i:=x] @ ys"
paulson@14208
  1005
apply (induct xs, simp)
nipkow@14187
  1006
apply(simp split:nat.split)
nipkow@14187
  1007
done
nipkow@14187
  1008
kleing@15868
  1009
lemma list_update_append:
kleing@15868
  1010
  "!!n. (xs @ ys) [n:= x] = 
kleing@15868
  1011
  (if n < length xs then xs[n:= x] @ ys else xs @ (ys [n-length xs:= x]))"
kleing@15868
  1012
by (induct xs) (auto split:nat.splits)
kleing@15868
  1013
nipkow@14402
  1014
lemma list_update_length [simp]:
nipkow@14402
  1015
 "(xs @ x # ys)[length xs := y] = (xs @ y # ys)"
nipkow@14402
  1016
by (induct xs, auto)
nipkow@14402
  1017
wenzelm@13114
  1018
lemma update_zip:
nipkow@13145
  1019
"!!i xy xs. length xs = length ys ==>
nipkow@13145
  1020
(zip xs ys)[i:=xy] = zip (xs[i:=fst xy]) (ys[i:=snd xy])"
nipkow@13145
  1021
by (induct ys) (auto, case_tac xs, auto split: nat.split)
wenzelm@13114
  1022
wenzelm@13114
  1023
lemma set_update_subset_insert: "!!i. set(xs[i:=x]) <= insert x (set xs)"
nipkow@13145
  1024
by (induct xs) (auto split: nat.split)
wenzelm@13114
  1025
wenzelm@13114
  1026
lemma set_update_subsetI: "[| set xs <= A; x:A |] ==> set(xs[i := x]) <= A"
nipkow@13145
  1027
by (blast dest!: set_update_subset_insert [THEN subsetD])
wenzelm@13114
  1028
kleing@15868
  1029
lemma set_update_memI: "!!n. n < length xs \<Longrightarrow> x \<in> set (xs[n := x])"
kleing@15868
  1030
by (induct xs) (auto split:nat.splits)
kleing@15868
  1031
wenzelm@13114
  1032
nipkow@15392
  1033
subsubsection {* @{text last} and @{text butlast} *}
wenzelm@13114
  1034
wenzelm@13142
  1035
lemma last_snoc [simp]: "last (xs @ [x]) = x"
nipkow@13145
  1036
by (induct xs) auto
wenzelm@13114
  1037
wenzelm@13142
  1038
lemma butlast_snoc [simp]: "butlast (xs @ [x]) = xs"
nipkow@13145
  1039
by (induct xs) auto
wenzelm@13114
  1040
nipkow@14302
  1041
lemma last_ConsL: "xs = [] \<Longrightarrow> last(x#xs) = x"
nipkow@14302
  1042
by(simp add:last.simps)
nipkow@14302
  1043
nipkow@14302
  1044
lemma last_ConsR: "xs \<noteq> [] \<Longrightarrow> last(x#xs) = last xs"
nipkow@14302
  1045
by(simp add:last.simps)
nipkow@14302
  1046
nipkow@14302
  1047
lemma last_append: "last(xs @ ys) = (if ys = [] then last xs else last ys)"
nipkow@14302
  1048
by (induct xs) (auto)
nipkow@14302
  1049
nipkow@14302
  1050
lemma last_appendL[simp]: "ys = [] \<Longrightarrow> last(xs @ ys) = last xs"
nipkow@14302
  1051
by(simp add:last_append)
nipkow@14302
  1052
nipkow@14302
  1053
lemma last_appendR[simp]: "ys \<noteq> [] \<Longrightarrow> last(xs @ ys) = last ys"
nipkow@14302
  1054
by(simp add:last_append)
nipkow@14302
  1055
nipkow@17762
  1056
lemma hd_rev: "xs \<noteq> [] \<Longrightarrow> hd(rev xs) = last xs"
nipkow@17762
  1057
by(rule rev_exhaust[of xs]) simp_all
nipkow@17762
  1058
nipkow@17762
  1059
lemma last_rev: "xs \<noteq> [] \<Longrightarrow> last(rev xs) = hd xs"
nipkow@17762
  1060
by(cases xs) simp_all
nipkow@17762
  1061
nipkow@17765
  1062
lemma last_in_set[simp]: "as \<noteq> [] \<Longrightarrow> last as \<in> set as"
nipkow@17765
  1063
by (induct as) auto
nipkow@17762
  1064
wenzelm@13142
  1065
lemma length_butlast [simp]: "length (butlast xs) = length xs - 1"
nipkow@13145
  1066
by (induct xs rule: rev_induct) auto
wenzelm@13114
  1067
wenzelm@13114
  1068
lemma butlast_append:
nipkow@13145
  1069
"!!ys. butlast (xs @ ys) = (if ys = [] then butlast xs else xs @ butlast ys)"
nipkow@13145
  1070
by (induct xs) auto
wenzelm@13114
  1071
wenzelm@13142
  1072
lemma append_butlast_last_id [simp]:
nipkow@13145
  1073
"xs \<noteq> [] ==> butlast xs @ [last xs] = xs"
nipkow@13145
  1074
by (induct xs) auto
wenzelm@13114
  1075
wenzelm@13142
  1076
lemma in_set_butlastD: "x : set (butlast xs) ==> x : set xs"
nipkow@13145
  1077
by (induct xs) (auto split: split_if_asm)
wenzelm@13114
  1078
wenzelm@13114
  1079
lemma in_set_butlast_appendI:
nipkow@13145
  1080
"x : set (butlast xs) | x : set (butlast ys) ==> x : set (butlast (xs @ ys))"
nipkow@13145
  1081
by (auto dest: in_set_butlastD simp add: butlast_append)
wenzelm@13114
  1082
nipkow@17501
  1083
lemma last_drop[simp]: "!!n. n < length xs \<Longrightarrow> last (drop n xs) = last xs"
nipkow@17501
  1084
apply (induct xs)
nipkow@17501
  1085
 apply simp
nipkow@17501
  1086
apply (auto split:nat.split)
nipkow@17501
  1087
done
nipkow@17501
  1088
nipkow@17589
  1089
lemma last_conv_nth: "xs\<noteq>[] \<Longrightarrow> last xs = xs!(length xs - 1)"
nipkow@17589
  1090
by(induct xs)(auto simp:neq_Nil_conv)
nipkow@17589
  1091
nipkow@15392
  1092
subsubsection {* @{text take} and @{text drop} *}
wenzelm@13114
  1093
wenzelm@13142
  1094
lemma take_0 [simp]: "take 0 xs = []"
nipkow@13145
  1095
by (induct xs) auto
wenzelm@13114
  1096
wenzelm@13142
  1097
lemma drop_0 [simp]: "drop 0 xs = xs"
nipkow@13145
  1098
by (induct xs) auto
wenzelm@13114
  1099
wenzelm@13142
  1100
lemma take_Suc_Cons [simp]: "take (Suc n) (x # xs) = x # take n xs"
nipkow@13145
  1101
by simp
wenzelm@13114
  1102
wenzelm@13142
  1103
lemma drop_Suc_Cons [simp]: "drop (Suc n) (x # xs) = drop n xs"
nipkow@13145
  1104
by simp
wenzelm@13114
  1105
wenzelm@13142
  1106
declare take_Cons [simp del] and drop_Cons [simp del]
wenzelm@13114
  1107
nipkow@15110
  1108
lemma take_Suc: "xs ~= [] ==> take (Suc n) xs = hd xs # take n (tl xs)"
nipkow@15110
  1109
by(clarsimp simp add:neq_Nil_conv)
nipkow@15110
  1110
nipkow@14187
  1111
lemma drop_Suc: "drop (Suc n) xs = drop n (tl xs)"
nipkow@14187
  1112
by(cases xs, simp_all)
nipkow@14187
  1113
nipkow@14187
  1114
lemma drop_tl: "!!n. drop n (tl xs) = tl(drop n xs)"
nipkow@14187
  1115
by(induct xs, simp_all add:drop_Cons drop_Suc split:nat.split)
nipkow@14187
  1116
nipkow@14187
  1117
lemma nth_via_drop: "!!n. drop n xs = y#ys \<Longrightarrow> xs!n = y"
paulson@14208
  1118
apply (induct xs, simp)
nipkow@14187
  1119
apply(simp add:drop_Cons nth_Cons split:nat.splits)
nipkow@14187
  1120
done
nipkow@14187
  1121
nipkow@13913
  1122
lemma take_Suc_conv_app_nth:
nipkow@13913
  1123
 "!!i. i < length xs \<Longrightarrow> take (Suc i) xs = take i xs @ [xs!i]"
paulson@14208
  1124
apply (induct xs, simp)
paulson@14208
  1125
apply (case_tac i, auto)
nipkow@13913
  1126
done
nipkow@13913
  1127
mehta@14591
  1128
lemma drop_Suc_conv_tl:
mehta@14591
  1129
  "!!i. i < length xs \<Longrightarrow> (xs!i) # (drop (Suc i) xs) = drop i xs"
mehta@14591
  1130
apply (induct xs, simp)
mehta@14591
  1131
apply (case_tac i, auto)
mehta@14591
  1132
done
mehta@14591
  1133
wenzelm@13142
  1134
lemma length_take [simp]: "!!xs. length (take n xs) = min (length xs) n"
nipkow@13145
  1135
by (induct n) (auto, case_tac xs, auto)
wenzelm@13114
  1136
wenzelm@13142
  1137
lemma length_drop [simp]: "!!xs. length (drop n xs) = (length xs - n)"
nipkow@13145
  1138
by (induct n) (auto, case_tac xs, auto)
wenzelm@13114
  1139
wenzelm@13142
  1140
lemma take_all [simp]: "!!xs. length xs <= n ==> take n xs = xs"
nipkow@13145
  1141
by (induct n) (auto, case_tac xs, auto)
wenzelm@13114
  1142
wenzelm@13142
  1143
lemma drop_all [simp]: "!!xs. length xs <= n ==> drop n xs = []"
nipkow@13145
  1144
by (induct n) (auto, case_tac xs, auto)
wenzelm@13114
  1145
wenzelm@13142
  1146
lemma take_append [simp]:
nipkow@13145
  1147
"!!xs. take n (xs @ ys) = (take n xs @ take (n - length xs) ys)"
nipkow@13145
  1148
by (induct n) (auto, case_tac xs, auto)
wenzelm@13114
  1149
wenzelm@13142
  1150
lemma drop_append [simp]:
nipkow@13145
  1151
"!!xs. drop n (xs @ ys) = drop n xs @ drop (n - length xs) ys"
nipkow@13145
  1152
by (induct n) (auto, case_tac xs, auto)
wenzelm@13114
  1153
wenzelm@13142
  1154
lemma take_take [simp]: "!!xs n. take n (take m xs) = take (min n m) xs"
paulson@14208
  1155
apply (induct m, auto)
paulson@14208
  1156
apply (case_tac xs, auto)
nipkow@15236
  1157
apply (case_tac n, auto)
nipkow@13145
  1158
done
wenzelm@13114
  1159
wenzelm@13142
  1160
lemma drop_drop [simp]: "!!xs. drop n (drop m xs) = drop (n + m) xs"
paulson@14208
  1161
apply (induct m, auto)
paulson@14208
  1162
apply (case_tac xs, auto)
nipkow@13145
  1163
done
wenzelm@13114
  1164
wenzelm@13114
  1165
lemma take_drop: "!!xs n. take n (drop m xs) = drop m (take (n + m) xs)"
paulson@14208
  1166
apply (induct m, auto)
paulson@14208
  1167
apply (case_tac xs, auto)
nipkow@13145
  1168
done
wenzelm@13114
  1169
nipkow@14802
  1170
lemma drop_take: "!!m n. drop n (take m xs) = take (m-n) (drop n xs)"
nipkow@14802
  1171
apply(induct xs)
nipkow@14802
  1172
 apply simp
nipkow@14802
  1173
apply(simp add: take_Cons drop_Cons split:nat.split)
nipkow@14802
  1174
done
nipkow@14802
  1175
wenzelm@13142
  1176
lemma append_take_drop_id [simp]: "!!xs. take n xs @ drop n xs = xs"
paulson@14208
  1177
apply (induct n, auto)
paulson@14208
  1178
apply (case_tac xs, auto)
nipkow@13145
  1179
done
wenzelm@13114
  1180
nipkow@15110
  1181
lemma take_eq_Nil[simp]: "!!n. (take n xs = []) = (n = 0 \<or> xs = [])"
nipkow@15110
  1182
apply(induct xs)
nipkow@15110
  1183
 apply simp
nipkow@15110
  1184
apply(simp add:take_Cons split:nat.split)
nipkow@15110
  1185
done
nipkow@15110
  1186
nipkow@15110
  1187
lemma drop_eq_Nil[simp]: "!!n. (drop n xs = []) = (length xs <= n)"
nipkow@15110
  1188
apply(induct xs)
nipkow@15110
  1189
apply simp
nipkow@15110
  1190
apply(simp add:drop_Cons split:nat.split)
nipkow@15110
  1191
done
nipkow@15110
  1192
wenzelm@13114
  1193
lemma take_map: "!!xs. take n (map f xs) = map f (take n xs)"
paulson@14208
  1194
apply (induct n, auto)
paulson@14208
  1195
apply (case_tac xs, auto)
nipkow@13145
  1196
done
wenzelm@13114
  1197
wenzelm@13142
  1198
lemma drop_map: "!!xs. drop n (map f xs) = map f (drop n xs)"
paulson@14208
  1199
apply (induct n, auto)
paulson@14208
  1200
apply (case_tac xs, auto)
nipkow@13145
  1201
done
wenzelm@13114
  1202
wenzelm@13114
  1203
lemma rev_take: "!!i. rev (take i xs) = drop (length xs - i) (rev xs)"
paulson@14208
  1204
apply (induct xs, auto)
paulson@14208
  1205
apply (case_tac i, auto)
nipkow@13145
  1206
done
wenzelm@13114
  1207
wenzelm@13114
  1208
lemma rev_drop: "!!i. rev (drop i xs) = take (length xs - i) (rev xs)"
paulson@14208
  1209
apply (induct xs, auto)
paulson@14208
  1210
apply (case_tac i, auto)
nipkow@13145
  1211
done
wenzelm@13114
  1212
wenzelm@13142
  1213
lemma nth_take [simp]: "!!n i. i < n ==> (take n xs)!i = xs!i"
paulson@14208
  1214
apply (induct xs, auto)
paulson@14208
  1215
apply (case_tac n, blast)
paulson@14208
  1216
apply (case_tac i, auto)
nipkow@13145
  1217
done
wenzelm@13114
  1218
wenzelm@13142
  1219
lemma nth_drop [simp]:
nipkow@13145
  1220
"!!xs i. n + i <= length xs ==> (drop n xs)!i = xs!(n + i)"
paulson@14208
  1221
apply (induct n, auto)
paulson@14208
  1222
apply (case_tac xs, auto)
nipkow@13145
  1223
done
nipkow@3507
  1224
nipkow@18423
  1225
lemma hd_drop_conv_nth: "\<lbrakk> xs \<noteq> []; n < length xs \<rbrakk> \<Longrightarrow> hd(drop n xs) = xs!n"
nipkow@18423
  1226
by(simp add: hd_conv_nth)
nipkow@18423
  1227
nipkow@14025
  1228
lemma set_take_subset: "\<And>n. set(take n xs) \<subseteq> set xs"
nipkow@14025
  1229
by(induct xs)(auto simp:take_Cons split:nat.split)
nipkow@14025
  1230
nipkow@14025
  1231
lemma set_drop_subset: "\<And>n. set(drop n xs) \<subseteq> set xs"
nipkow@14025
  1232
by(induct xs)(auto simp:drop_Cons split:nat.split)
nipkow@14025
  1233
nipkow@14187
  1234
lemma in_set_takeD: "x : set(take n xs) \<Longrightarrow> x : set xs"
nipkow@14187
  1235
using set_take_subset by fast
nipkow@14187
  1236
nipkow@14187
  1237
lemma in_set_dropD: "x : set(drop n xs) \<Longrightarrow> x : set xs"
nipkow@14187
  1238
using set_drop_subset by fast
nipkow@14187
  1239
wenzelm@13114
  1240
lemma append_eq_conv_conj:
nipkow@13145
  1241
"!!zs. (xs @ ys = zs) = (xs = take (length xs) zs \<and> ys = drop (length xs) zs)"
paulson@14208
  1242
apply (induct xs, simp, clarsimp)
paulson@14208
  1243
apply (case_tac zs, auto)
nipkow@13145
  1244
done
wenzelm@13142
  1245
paulson@14050
  1246
lemma take_add [rule_format]: 
paulson@14050
  1247
    "\<forall>i. i+j \<le> length(xs) --> take (i+j) xs = take i xs @ take j (drop i xs)"
paulson@14050
  1248
apply (induct xs, auto) 
paulson@14050
  1249
apply (case_tac i, simp_all) 
paulson@14050
  1250
done
paulson@14050
  1251
nipkow@14300
  1252
lemma append_eq_append_conv_if:
nipkow@14300
  1253
 "!! ys\<^isub>1. (xs\<^isub>1 @ xs\<^isub>2 = ys\<^isub>1 @ ys\<^isub>2) =
nipkow@14300
  1254
  (if size xs\<^isub>1 \<le> size ys\<^isub>1
nipkow@14300
  1255
   then xs\<^isub>1 = take (size xs\<^isub>1) ys\<^isub>1 \<and> xs\<^isub>2 = drop (size xs\<^isub>1) ys\<^isub>1 @ ys\<^isub>2
nipkow@14300
  1256
   else take (size ys\<^isub>1) xs\<^isub>1 = ys\<^isub>1 \<and> drop (size ys\<^isub>1) xs\<^isub>1 @ xs\<^isub>2 = ys\<^isub>2)"
nipkow@14300
  1257
apply(induct xs\<^isub>1)
nipkow@14300
  1258
 apply simp
nipkow@14300
  1259
apply(case_tac ys\<^isub>1)
nipkow@14300
  1260
apply simp_all
nipkow@14300
  1261
done
nipkow@14300
  1262
nipkow@15110
  1263
lemma take_hd_drop:
nipkow@15110
  1264
  "!!n. n < length xs \<Longrightarrow> take n xs @ [hd (drop n xs)] = take (n+1) xs"
nipkow@15110
  1265
apply(induct xs)
nipkow@15110
  1266
apply simp
nipkow@15110
  1267
apply(simp add:drop_Cons split:nat.split)
nipkow@15110
  1268
done
nipkow@15110
  1269
nipkow@17501
  1270
lemma id_take_nth_drop:
nipkow@17501
  1271
 "i < length xs \<Longrightarrow> xs = take i xs @ xs!i # drop (Suc i) xs" 
nipkow@17501
  1272
proof -
nipkow@17501
  1273
  assume si: "i < length xs"
nipkow@17501
  1274
  hence "xs = take (Suc i) xs @ drop (Suc i) xs" by auto
nipkow@17501
  1275
  moreover
nipkow@17501
  1276
  from si have "take (Suc i) xs = take i xs @ [xs!i]"
nipkow@17501
  1277
    apply (rule_tac take_Suc_conv_app_nth) by arith
nipkow@17501
  1278
  ultimately show ?thesis by auto
nipkow@17501
  1279
qed
nipkow@17501
  1280
  
nipkow@17501
  1281
lemma upd_conv_take_nth_drop:
nipkow@17501
  1282
 "i < length xs \<Longrightarrow> xs[i:=a] = take i xs @ a # drop (Suc i) xs"
nipkow@17501
  1283
proof -
nipkow@17501
  1284
  assume i: "i < length xs"
nipkow@17501
  1285
  have "xs[i:=a] = (take i xs @ xs!i # drop (Suc i) xs)[i:=a]"
nipkow@17501
  1286
    by(rule arg_cong[OF id_take_nth_drop[OF i]])
nipkow@17501
  1287
  also have "\<dots> = take i xs @ a # drop (Suc i) xs"
nipkow@17501
  1288
    using i by (simp add: list_update_append)
nipkow@17501
  1289
  finally show ?thesis .
nipkow@17501
  1290
qed
nipkow@17501
  1291
wenzelm@13114
  1292
nipkow@15392
  1293
subsubsection {* @{text takeWhile} and @{text dropWhile} *}
wenzelm@13114
  1294
wenzelm@13142
  1295
lemma takeWhile_dropWhile_id [simp]: "takeWhile P xs @ dropWhile P xs = xs"
nipkow@13145
  1296
by (induct xs) auto
wenzelm@13114
  1297
wenzelm@13142
  1298
lemma takeWhile_append1 [simp]:
nipkow@13145
  1299
"[| x:set xs; ~P(x)|] ==> takeWhile P (xs @ ys) = takeWhile P xs"
nipkow@13145
  1300
by (induct xs) auto
wenzelm@13114
  1301
wenzelm@13142
  1302
lemma takeWhile_append2 [simp]:
nipkow@13145
  1303
"(!!x. x : set xs ==> P x) ==> takeWhile P (xs @ ys) = xs @ takeWhile P ys"
nipkow@13145
  1304
by (induct xs) auto
wenzelm@13114
  1305
wenzelm@13142
  1306
lemma takeWhile_tail: "\<not> P x ==> takeWhile P (xs @ (x#l)) = takeWhile P xs"
nipkow@13145
  1307
by (induct xs) auto
wenzelm@13114
  1308
wenzelm@13142
  1309
lemma dropWhile_append1 [simp]:
nipkow@13145
  1310
"[| x : set xs; ~P(x)|] ==> dropWhile P (xs @ ys) = (dropWhile P xs)@ys"
nipkow@13145
  1311
by (induct xs) auto
wenzelm@13114
  1312
wenzelm@13142
  1313
lemma dropWhile_append2 [simp]:
nipkow@13145
  1314
"(!!x. x:set xs ==> P(x)) ==> dropWhile P (xs @ ys) = dropWhile P ys"
nipkow@13145
  1315
by (induct xs) auto
wenzelm@13114
  1316
wenzelm@13142
  1317
lemma set_take_whileD: "x : set (takeWhile P xs) ==> x : set xs \<and> P x"
nipkow@13145
  1318
by (induct xs) (auto split: split_if_asm)
wenzelm@13114
  1319
nipkow@13913
  1320
lemma takeWhile_eq_all_conv[simp]:
nipkow@13913
  1321
 "(takeWhile P xs = xs) = (\<forall>x \<in> set xs. P x)"
nipkow@13913
  1322
by(induct xs, auto)
nipkow@13913
  1323
nipkow@13913
  1324
lemma dropWhile_eq_Nil_conv[simp]:
nipkow@13913
  1325
 "(dropWhile P xs = []) = (\<forall>x \<in> set xs. P x)"
nipkow@13913
  1326
by(induct xs, auto)
nipkow@13913
  1327
nipkow@13913
  1328
lemma dropWhile_eq_Cons_conv:
nipkow@13913
  1329
 "(dropWhile P xs = y#ys) = (xs = takeWhile P xs @ y # ys & \<not> P y)"
nipkow@13913
  1330
by(induct xs, auto)
nipkow@13913
  1331
nipkow@17501
  1332
text{* The following two lemmmas could be generalized to an arbitrary
nipkow@17501
  1333
property. *}
nipkow@17501
  1334
nipkow@17501
  1335
lemma takeWhile_neq_rev: "\<lbrakk>distinct xs; x \<in> set xs\<rbrakk> \<Longrightarrow>
nipkow@17501
  1336
 takeWhile (\<lambda>y. y \<noteq> x) (rev xs) = rev (tl (dropWhile (\<lambda>y. y \<noteq> x) xs))"
nipkow@17501
  1337
by(induct xs) (auto simp: takeWhile_tail[where l="[]"])
nipkow@17501
  1338
nipkow@17501
  1339
lemma dropWhile_neq_rev: "\<lbrakk>distinct xs; x \<in> set xs\<rbrakk> \<Longrightarrow>
nipkow@17501
  1340
  dropWhile (\<lambda>y. y \<noteq> x) (rev xs) = x # rev (takeWhile (\<lambda>y. y \<noteq> x) xs)"
nipkow@17501
  1341
apply(induct xs)
nipkow@17501
  1342
 apply simp
nipkow@17501
  1343
apply auto
nipkow@17501
  1344
apply(subst dropWhile_append2)
nipkow@17501
  1345
apply auto
nipkow@17501
  1346
done
nipkow@17501
  1347
nipkow@18423
  1348
lemma takeWhile_not_last:
nipkow@18423
  1349
 "\<lbrakk> xs \<noteq> []; distinct xs\<rbrakk> \<Longrightarrow> takeWhile (\<lambda>y. y \<noteq> last xs) xs = butlast xs"
nipkow@18423
  1350
apply(induct xs)
nipkow@18423
  1351
 apply simp
nipkow@18423
  1352
apply(case_tac xs)
nipkow@18423
  1353
apply(auto)
nipkow@18423
  1354
done
nipkow@18423
  1355
krauss@19770
  1356
lemma takeWhile_cong [fundef_cong, recdef_cong]:
krauss@18336
  1357
  "[| l = k; !!x. x : set l ==> P x = Q x |] 
krauss@18336
  1358
  ==> takeWhile P l = takeWhile Q k"
krauss@18336
  1359
  by (induct k fixing: l, simp_all)
krauss@18336
  1360
krauss@19770
  1361
lemma dropWhile_cong [fundef_cong, recdef_cong]:
krauss@18336
  1362
  "[| l = k; !!x. x : set l ==> P x = Q x |] 
krauss@18336
  1363
  ==> dropWhile P l = dropWhile Q k"
krauss@18336
  1364
  by (induct k fixing: l, simp_all)
krauss@18336
  1365
wenzelm@13114
  1366
nipkow@15392
  1367
subsubsection {* @{text zip} *}
wenzelm@13114
  1368
wenzelm@13142
  1369
lemma zip_Nil [simp]: "zip [] ys = []"
nipkow@13145
  1370
by (induct ys) auto
wenzelm@13114
  1371
wenzelm@13142
  1372
lemma zip_Cons_Cons [simp]: "zip (x # xs) (y # ys) = (x, y) # zip xs ys"
nipkow@13145
  1373
by simp
wenzelm@13114
  1374
wenzelm@13142
  1375
declare zip_Cons [simp del]
wenzelm@13114
  1376
nipkow@15281
  1377
lemma zip_Cons1:
nipkow@15281
  1378
 "zip (x#xs) ys = (case ys of [] \<Rightarrow> [] | y#ys \<Rightarrow> (x,y)#zip xs ys)"
nipkow@15281
  1379
by(auto split:list.split)
nipkow@15281
  1380
wenzelm@13142
  1381
lemma length_zip [simp]:
nipkow@13145
  1382
"!!xs. length (zip xs ys) = min (length xs) (length ys)"
paulson@14208
  1383
apply (induct ys, simp)
paulson@14208
  1384
apply (case_tac xs, auto)
nipkow@13145
  1385
done
wenzelm@13114
  1386
wenzelm@13114
  1387
lemma zip_append1:
nipkow@13145
  1388
"!!xs. zip (xs @ ys) zs =
nipkow@13145
  1389
zip xs (take (length xs) zs) @ zip ys (drop (length xs) zs)"
paulson@14208
  1390
apply (induct zs, simp)
paulson@14208
  1391
apply (case_tac xs, simp_all)
nipkow@13145
  1392
done
wenzelm@13114
  1393
wenzelm@13114
  1394
lemma zip_append2:
nipkow@13145
  1395
"!!ys. zip xs (ys @ zs) =
nipkow@13145
  1396
zip (take (length ys) xs) ys @ zip (drop (length ys) xs) zs"
paulson@14208
  1397
apply (induct xs, simp)
paulson@14208
  1398
apply (case_tac ys, simp_all)
nipkow@13145
  1399
done
wenzelm@13114
  1400
wenzelm@13142
  1401
lemma zip_append [simp]:
wenzelm@13142
  1402
 "[| length xs = length us; length ys = length vs |] ==>
nipkow@13145
  1403
zip (xs@ys) (us@vs) = zip xs us @ zip ys vs"
nipkow@13145
  1404
by (simp add: zip_append1)
wenzelm@13114
  1405
wenzelm@13114
  1406
lemma zip_rev:
nipkow@14247
  1407
"length xs = length ys ==> zip (rev xs) (rev ys) = rev (zip xs ys)"
nipkow@14247
  1408
by (induct rule:list_induct2, simp_all)
wenzelm@13114
  1409
wenzelm@13142
  1410
lemma nth_zip [simp]:
nipkow@13145
  1411
"!!i xs. [| i < length xs; i < length ys|] ==> (zip xs ys)!i = (xs!i, ys!i)"
paulson@14208
  1412
apply (induct ys, simp)
nipkow@13145
  1413
apply (case_tac xs)
nipkow@13145
  1414
 apply (simp_all add: nth.simps split: nat.split)
nipkow@13145
  1415
done
wenzelm@13114
  1416
wenzelm@13114
  1417
lemma set_zip:
nipkow@13145
  1418
"set (zip xs ys) = {(xs!i, ys!i) | i. i < min (length xs) (length ys)}"
nipkow@13145
  1419
by (simp add: set_conv_nth cong: rev_conj_cong)
wenzelm@13114
  1420
wenzelm@13114
  1421
lemma zip_update:
nipkow@13145
  1422
"length xs = length ys ==> zip (xs[i:=x]) (ys[i:=y]) = (zip xs ys)[i:=(x,y)]"
nipkow@13145
  1423
by (rule sym, simp add: update_zip)
wenzelm@13114
  1424
wenzelm@13142
  1425
lemma zip_replicate [simp]:
nipkow@13145
  1426
"!!j. zip (replicate i x) (replicate j y) = replicate (min i j) (x,y)"
paulson@14208
  1427
apply (induct i, auto)
paulson@14208
  1428
apply (case_tac j, auto)
nipkow@13145
  1429
done
wenzelm@13114
  1430
nipkow@19487
  1431
lemma take_zip:
nipkow@19487
  1432
 "!!xs ys. take n (zip xs ys) = zip (take n xs) (take n ys)"
nipkow@19487
  1433
apply (induct n)
nipkow@19487
  1434
 apply simp
nipkow@19487
  1435
apply (case_tac xs, simp)
nipkow@19487
  1436
apply (case_tac ys, simp_all)
nipkow@19487
  1437
done
nipkow@19487
  1438
nipkow@19487
  1439
lemma drop_zip:
nipkow@19487
  1440
 "!!xs ys. drop n (zip xs ys) = zip (drop n xs) (drop n ys)"
nipkow@19487
  1441
apply (induct n)
nipkow@19487
  1442
 apply simp
nipkow@19487
  1443
apply (case_tac xs, simp)
nipkow@19487
  1444
apply (case_tac ys, simp_all)
nipkow@19487
  1445
done
nipkow@19487
  1446
wenzelm@13142
  1447
nipkow@15392
  1448
subsubsection {* @{text list_all2} *}
wenzelm@13114
  1449
kleing@14316
  1450
lemma list_all2_lengthD [intro?]: 
kleing@14316
  1451
  "list_all2 P xs ys ==> length xs = length ys"
haftmann@19607
  1452
  by (simp add: list_all2_def)
haftmann@19607
  1453
haftmann@19787
  1454
lemma list_all2_Nil [iff, code]: "list_all2 P [] ys = (ys = [])"
haftmann@19607
  1455
  by (simp add: list_all2_def)
haftmann@19607
  1456
haftmann@19787
  1457
lemma list_all2_Nil2 [iff, code]: "list_all2 P xs [] = (xs = [])"
haftmann@19787
  1458
  by (simp add: list_all2_def)
haftmann@19607
  1459
haftmann@19607
  1460
lemma list_all2_Cons [iff, code]:
haftmann@19607
  1461
  "list_all2 P (x # xs) (y # ys) = (P x y \<and> list_all2 P xs ys)"
haftmann@19607
  1462
  by (auto simp add: list_all2_def)
wenzelm@13114
  1463
wenzelm@13114
  1464
lemma list_all2_Cons1:
nipkow@13145
  1465
"list_all2 P (x # xs) ys = (\<exists>z zs. ys = z # zs \<and> P x z \<and> list_all2 P xs zs)"
nipkow@13145
  1466
by (cases ys) auto
wenzelm@13114
  1467
wenzelm@13114
  1468
lemma list_all2_Cons2:
nipkow@13145
  1469
"list_all2 P xs (y # ys) = (\<exists>z zs. xs = z # zs \<and> P z y \<and> list_all2 P zs ys)"
nipkow@13145
  1470
by (cases xs) auto
wenzelm@13114
  1471
wenzelm@13142
  1472
lemma list_all2_rev [iff]:
nipkow@13145
  1473
"list_all2 P (rev xs) (rev ys) = list_all2 P xs ys"
nipkow@13145
  1474
by (simp add: list_all2_def zip_rev cong: conj_cong)
wenzelm@13114
  1475
kleing@13863
  1476
lemma list_all2_rev1:
kleing@13863
  1477
"list_all2 P (rev xs) ys = list_all2 P xs (rev ys)"
kleing@13863
  1478
by (subst list_all2_rev [symmetric]) simp
kleing@13863
  1479
wenzelm@13114
  1480
lemma list_all2_append1:
nipkow@13145
  1481
"list_all2 P (xs @ ys) zs =
nipkow@13145
  1482
(EX us vs. zs = us @ vs \<and> length us = length xs \<and> length vs = length ys \<and>
nipkow@13145
  1483
list_all2 P xs us \<and> list_all2 P ys vs)"
nipkow@13145
  1484
apply (simp add: list_all2_def zip_append1)
nipkow@13145
  1485
apply (rule iffI)
nipkow@13145
  1486
 apply (rule_tac x = "take (length xs) zs" in exI)
nipkow@13145
  1487
 apply (rule_tac x = "drop (length xs) zs" in exI)
paulson@14208
  1488
 apply (force split: nat_diff_split simp add: min_def, clarify)
nipkow@13145
  1489
apply (simp add: ball_Un)
nipkow@13145
  1490
done
wenzelm@13114
  1491
wenzelm@13114
  1492
lemma list_all2_append2:
nipkow@13145
  1493
"list_all2 P xs (ys @ zs) =
nipkow@13145
  1494
(EX us vs. xs = us @ vs \<and> length us = length ys \<and> length vs = length zs \<and>
nipkow@13145
  1495
list_all2 P us ys \<and> list_all2 P vs zs)"
nipkow@13145
  1496
apply (simp add: list_all2_def zip_append2)
nipkow@13145
  1497
apply (rule iffI)
nipkow@13145
  1498
 apply (rule_tac x = "take (length ys) xs" in exI)
nipkow@13145
  1499
 apply (rule_tac x = "drop (length ys) xs" in exI)
paulson@14208
  1500
 apply (force split: nat_diff_split simp add: min_def, clarify)
nipkow@13145
  1501
apply (simp add: ball_Un)
nipkow@13145
  1502
done
wenzelm@13114
  1503
kleing@13863
  1504
lemma list_all2_append:
nipkow@14247
  1505
  "length xs = length ys \<Longrightarrow>
nipkow@14247
  1506
  list_all2 P (xs@us) (ys@vs) = (list_all2 P xs ys \<and> list_all2 P us vs)"
nipkow@14247
  1507
by (induct rule:list_induct2, simp_all)
kleing@13863
  1508
kleing@13863
  1509
lemma list_all2_appendI [intro?, trans]:
kleing@13863
  1510
  "\<lbrakk> list_all2 P a b; list_all2 P c d \<rbrakk> \<Longrightarrow> list_all2 P (a@c) (b@d)"
kleing@13863
  1511
  by (simp add: list_all2_append list_all2_lengthD)
kleing@13863
  1512
wenzelm@13114
  1513
lemma list_all2_conv_all_nth:
nipkow@13145
  1514
"list_all2 P xs ys =
nipkow@13145
  1515
(length xs = length ys \<and> (\<forall>i < length xs. P (xs!i) (ys!i)))"
nipkow@13145
  1516
by (force simp add: list_all2_def set_zip)
wenzelm@13114
  1517
berghofe@13883
  1518
lemma list_all2_trans:
berghofe@13883
  1519
  assumes tr: "!!a b c. P1 a b ==> P2 b c ==> P3 a c"
berghofe@13883
  1520
  shows "!!bs cs. list_all2 P1 as bs ==> list_all2 P2 bs cs ==> list_all2 P3 as cs"
berghofe@13883
  1521
        (is "!!bs cs. PROP ?Q as bs cs")
berghofe@13883
  1522
proof (induct as)
berghofe@13883
  1523
  fix x xs bs assume I1: "!!bs cs. PROP ?Q xs bs cs"
berghofe@13883
  1524
  show "!!cs. PROP ?Q (x # xs) bs cs"
berghofe@13883
  1525
  proof (induct bs)
berghofe@13883
  1526
    fix y ys cs assume I2: "!!cs. PROP ?Q (x # xs) ys cs"
berghofe@13883
  1527
    show "PROP ?Q (x # xs) (y # ys) cs"
berghofe@13883
  1528
      by (induct cs) (auto intro: tr I1 I2)
berghofe@13883
  1529
  qed simp
berghofe@13883
  1530
qed simp
berghofe@13883
  1531
kleing@13863
  1532
lemma list_all2_all_nthI [intro?]:
kleing@13863
  1533
  "length a = length b \<Longrightarrow> (\<And>n. n < length a \<Longrightarrow> P (a!n) (b!n)) \<Longrightarrow> list_all2 P a b"
kleing@13863
  1534
  by (simp add: list_all2_conv_all_nth)
kleing@13863
  1535
paulson@14395
  1536
lemma list_all2I:
paulson@14395
  1537
  "\<forall>x \<in> set (zip a b). split P x \<Longrightarrow> length a = length b \<Longrightarrow> list_all2 P a b"
paulson@14395
  1538
  by (simp add: list_all2_def)
paulson@14395
  1539
kleing@14328
  1540
lemma list_all2_nthD:
kleing@13863
  1541
  "\<lbrakk> list_all2 P xs ys; p < size xs \<rbrakk> \<Longrightarrow> P (xs!p) (ys!p)"
kleing@13863
  1542
  by (simp add: list_all2_conv_all_nth)
kleing@13863
  1543
nipkow@14302
  1544
lemma list_all2_nthD2:
nipkow@14302
  1545
  "\<lbrakk>list_all2 P xs ys; p < size ys\<rbrakk> \<Longrightarrow> P (xs!p) (ys!p)"
nipkow@14302
  1546
  by (frule list_all2_lengthD) (auto intro: list_all2_nthD)
nipkow@14302
  1547
kleing@13863
  1548
lemma list_all2_map1: 
kleing@13863
  1549
  "list_all2 P (map f as) bs = list_all2 (\<lambda>x y. P (f x) y) as bs"
kleing@13863
  1550
  by (simp add: list_all2_conv_all_nth)
kleing@13863
  1551
kleing@13863
  1552
lemma list_all2_map2: 
kleing@13863
  1553
  "list_all2 P as (map f bs) = list_all2 (\<lambda>x y. P x (f y)) as bs"
kleing@13863
  1554
  by (auto simp add: list_all2_conv_all_nth)
kleing@13863
  1555
kleing@14316
  1556
lemma list_all2_refl [intro?]:
kleing@13863
  1557
  "(\<And>x. P x x) \<Longrightarrow> list_all2 P xs xs"
kleing@13863
  1558
  by (simp add: list_all2_conv_all_nth)
kleing@13863
  1559
kleing@13863
  1560
lemma list_all2_update_cong:
kleing@13863
  1561
  "\<lbrakk> i<size xs; list_all2 P xs ys; P x y \<rbrakk> \<Longrightarrow> list_all2 P (xs[i:=x]) (ys[i:=y])"
kleing@13863
  1562
  by (simp add: list_all2_conv_all_nth nth_list_update)
kleing@13863
  1563
kleing@13863
  1564
lemma list_all2_update_cong2:
kleing@13863
  1565
  "\<lbrakk>list_all2 P xs ys; P x y; i < length ys\<rbrakk> \<Longrightarrow> list_all2 P (xs[i:=x]) (ys[i:=y])"
kleing@13863
  1566
  by (simp add: list_all2_lengthD list_all2_update_cong)
kleing@13863
  1567
nipkow@14302
  1568
lemma list_all2_takeI [simp,intro?]:
nipkow@14302
  1569
  "\<And>n ys. list_all2 P xs ys \<Longrightarrow> list_all2 P (take n xs) (take n ys)"
nipkow@14302
  1570
  apply (induct xs)
nipkow@14302
  1571
   apply simp
nipkow@14302
  1572
  apply (clarsimp simp add: list_all2_Cons1)
nipkow@14302
  1573
  apply (case_tac n)
nipkow@14302
  1574
  apply auto
nipkow@14302
  1575
  done
nipkow@14302
  1576
nipkow@14302
  1577
lemma list_all2_dropI [simp,intro?]:
kleing@13863
  1578
  "\<And>n bs. list_all2 P as bs \<Longrightarrow> list_all2 P (drop n as) (drop n bs)"
paulson@14208
  1579
  apply (induct as, simp)
kleing@13863
  1580
  apply (clarsimp simp add: list_all2_Cons1)
paulson@14208
  1581
  apply (case_tac n, simp, simp)
kleing@13863
  1582
  done
kleing@13863
  1583
kleing@14327
  1584
lemma list_all2_mono [intro?]:
kleing@13863
  1585
  "\<And>y. list_all2 P x y \<Longrightarrow> (\<And>x y. P x y \<Longrightarrow> Q x y) \<Longrightarrow> list_all2 Q x y"
paulson@14208
  1586
  apply (induct x, simp)
paulson@14208
  1587
  apply (case_tac y, auto)
kleing@13863
  1588
  done
kleing@13863
  1589
wenzelm@13142
  1590
nipkow@15392
  1591
subsubsection {* @{text foldl} and @{text foldr} *}
wenzelm@13142
  1592
wenzelm@13142
  1593
lemma foldl_append [simp]:
nipkow@13145
  1594
"!!a. foldl f a (xs @ ys) = foldl f (foldl f a xs) ys"
nipkow@13145
  1595
by (induct xs) auto
wenzelm@13142
  1596
nipkow@14402
  1597
lemma foldr_append[simp]: "foldr f (xs @ ys) a = foldr f xs (foldr f ys a)"
nipkow@14402
  1598
by (induct xs) auto
nipkow@14402
  1599
krauss@19770
  1600
lemma foldl_cong [fundef_cong, recdef_cong]:
krauss@18336
  1601
  "[| a = b; l = k; !!a x. x : set l ==> f a x = g a x |] 
krauss@18336
  1602
  ==> foldl f a l = foldl g b k"
krauss@18336
  1603
  by (induct k fixing: a b l, simp_all)
krauss@18336
  1604
krauss@19770
  1605
lemma foldr_cong [fundef_cong, recdef_cong]:
krauss@18336
  1606
  "[| a = b; l = k; !!a x. x : set l ==> f x a = g x a |] 
krauss@18336
  1607
  ==> foldr f l a = foldr g k b"
krauss@18336
  1608
  by (induct k fixing: a b l, simp_all)
krauss@18336
  1609
nipkow@14402
  1610
lemma foldr_foldl: "foldr f xs a = foldl (%x y. f y x) a (rev xs)"
nipkow@14402
  1611
by (induct xs) auto
nipkow@14402
  1612
nipkow@14402
  1613
lemma foldl_foldr: "foldl f a xs = foldr (%x y. f y x) (rev xs) a"
nipkow@14402
  1614
by (simp add: foldr_foldl [of "%x y. f y x" "rev xs"])
nipkow@14402
  1615
wenzelm@13142
  1616
text {*
nipkow@13145
  1617
Note: @{text "n \<le> foldl (op +) n ns"} looks simpler, but is more
nipkow@13145
  1618
difficult to use because it requires an additional transitivity step.
wenzelm@13142
  1619
*}
wenzelm@13142
  1620
wenzelm@13142
  1621
lemma start_le_sum: "!!n::nat. m <= n ==> m <= foldl (op +) n ns"
nipkow@13145
  1622
by (induct ns) auto
wenzelm@13142
  1623
wenzelm@13142
  1624
lemma elem_le_sum: "!!n::nat. n : set ns ==> n <= foldl (op +) 0 ns"
nipkow@13145
  1625
by (force intro: start_le_sum simp add: in_set_conv_decomp)
wenzelm@13142
  1626
wenzelm@13142
  1627
lemma sum_eq_0_conv [iff]:
nipkow@13145
  1628
"!!m::nat. (foldl (op +) m ns = 0) = (m = 0 \<and> (\<forall>n \<in> set ns. n = 0))"
nipkow@13145
  1629
by (induct ns) auto
wenzelm@13114
  1630
wenzelm@13114
  1631
nipkow@15392
  1632
subsubsection {* @{text upto} *}
wenzelm@13114
  1633
nipkow@17090
  1634
lemma upt_rec[code]: "[i..<j] = (if i<j then i#[Suc i..<j] else [])"
nipkow@17090
  1635
-- {* simp does not terminate! *}
nipkow@13145
  1636
by (induct j) auto
wenzelm@13142
  1637
nipkow@15425
  1638
lemma upt_conv_Nil [simp]: "j <= i ==> [i..<j] = []"
nipkow@13145
  1639
by (subst upt_rec) simp
wenzelm@13114
  1640
nipkow@15425
  1641
lemma upt_eq_Nil_conv[simp]: "([i..<j] = []) = (j = 0 \<or> j <= i)"
nipkow@15281
  1642
by(induct j)simp_all
nipkow@15281
  1643
nipkow@15281
  1644
lemma upt_eq_Cons_conv:
nipkow@15425
  1645
 "!!x xs. ([i..<j] = x#xs) = (i < j & i = x & [i+1..<j] = xs)"
nipkow@15281
  1646
apply(induct j)
nipkow@15281
  1647
 apply simp
nipkow@15281
  1648
apply(clarsimp simp add: append_eq_Cons_conv)
nipkow@15281
  1649
apply arith
nipkow@15281
  1650
done
nipkow@15281
  1651
nipkow@15425
  1652
lemma upt_Suc_append: "i <= j ==> [i..<(Suc j)] = [i..<j]@[j]"
nipkow@13145
  1653
-- {* Only needed if @{text upt_Suc} is deleted from the simpset. *}
nipkow@13145
  1654
by simp
wenzelm@13114
  1655
nipkow@15425
  1656
lemma upt_conv_Cons: "i < j ==> [i..<j] = i # [Suc i..<j]"
nipkow@13145
  1657
apply(rule trans)
nipkow@13145
  1658
apply(subst upt_rec)
paulson@14208
  1659
 prefer 2 apply (rule refl, simp)
nipkow@13145
  1660
done
wenzelm@13114
  1661
nipkow@15425
  1662
lemma upt_add_eq_append: "i<=j ==> [i..<j+k] = [i..<j]@[j..<j+k]"
nipkow@13145
  1663
-- {* LOOPS as a simprule, since @{text "j <= j"}. *}
nipkow@13145
  1664
by (induct k) auto
wenzelm@13114
  1665
nipkow@15425
  1666
lemma length_upt [simp]: "length [i..<j] = j - i"
nipkow@13145
  1667
by (induct j) (auto simp add: Suc_diff_le)
wenzelm@13114
  1668
nipkow@15425
  1669
lemma nth_upt [simp]: "i + k < j ==> [i..<j] ! k = i + k"
nipkow@13145
  1670
apply (induct j)
nipkow@13145
  1671
apply (auto simp add: less_Suc_eq nth_append split: nat_diff_split)
nipkow@13145
  1672
done
wenzelm@13114
  1673
nipkow@17906
  1674
nipkow@17906
  1675
lemma hd_upt[simp]: "i < j \<Longrightarrow> hd[i..<j] = i"
nipkow@17906
  1676
by(simp add:upt_conv_Cons)
nipkow@17906
  1677
nipkow@17906
  1678
lemma last_upt[simp]: "i < j \<Longrightarrow> last[i..<j] = j - 1"
nipkow@17906
  1679
apply(cases j)
nipkow@17906
  1680
 apply simp
nipkow@17906
  1681
by(simp add:upt_Suc_append)
nipkow@17906
  1682
nipkow@15425
  1683
lemma take_upt [simp]: "!!i. i+m <= n ==> take m [i..<n] = [i..<i+m]"
paulson@14208
  1684
apply (induct m, simp)
nipkow@13145
  1685
apply (subst upt_rec)
nipkow@13145
  1686
apply (rule sym)
nipkow@13145
  1687
apply (subst upt_rec)
nipkow@13145
  1688
apply (simp del: upt.simps)
nipkow@13145
  1689
done
nipkow@3507
  1690
nipkow@17501
  1691
lemma drop_upt[simp]: "drop m [i..<j] = [i+m..<j]"
nipkow@17501
  1692
apply(induct j)
nipkow@17501
  1693
apply auto
nipkow@17501
  1694
done
nipkow@17501
  1695
nipkow@15425
  1696
lemma map_Suc_upt: "map Suc [m..<n] = [Suc m..n]"
nipkow@13145
  1697
by (induct n) auto
wenzelm@13114
  1698
nipkow@15425
  1699
lemma nth_map_upt: "!!i. i < n-m ==> (map f [m..<n]) ! i = f(m+i)"
nipkow@13145
  1700
apply (induct n m rule: diff_induct)
nipkow@13145
  1701
prefer 3 apply (subst map_Suc_upt[symmetric])
nipkow@13145
  1702
apply (auto simp add: less_diff_conv nth_upt)
nipkow@13145
  1703
done
wenzelm@13114
  1704
berghofe@13883
  1705
lemma nth_take_lemma:
berghofe@13883
  1706
  "!!xs ys. k <= length xs ==> k <= length ys ==>
berghofe@13883
  1707
     (!!i. i < k --> xs!i = ys!i) ==> take k xs = take k ys"
berghofe@13883
  1708
apply (atomize, induct k)
paulson@14208
  1709
apply (simp_all add: less_Suc_eq_0_disj all_conj_distrib, clarify)
nipkow@13145
  1710
txt {* Both lists must be non-empty *}
paulson@14208
  1711
apply (case_tac xs, simp)
paulson@14208
  1712
apply (case_tac ys, clarify)
nipkow@13145
  1713
 apply (simp (no_asm_use))
nipkow@13145
  1714
apply clarify
nipkow@13145
  1715
txt {* prenexing's needed, not miniscoping *}
nipkow@13145
  1716
apply (simp (no_asm_use) add: all_simps [symmetric] del: all_simps)
nipkow@13145
  1717
apply blast
nipkow@13145
  1718
done
wenzelm@13114
  1719
wenzelm@13114
  1720
lemma nth_equalityI:
wenzelm@13114
  1721
 "[| length xs = length ys; ALL i < length xs. xs!i = ys!i |] ==> xs = ys"
nipkow@13145
  1722
apply (frule nth_take_lemma [OF le_refl eq_imp_le])
nipkow@13145
  1723
apply (simp_all add: take_all)
nipkow@13145
  1724
done
wenzelm@13142
  1725
kleing@13863
  1726
(* needs nth_equalityI *)
kleing@13863
  1727
lemma list_all2_antisym:
kleing@13863
  1728
  "\<lbrakk> (\<And>x y. \<lbrakk>P x y; Q y x\<rbrakk> \<Longrightarrow> x = y); list_all2 P xs ys; list_all2 Q ys xs \<rbrakk> 
kleing@13863
  1729
  \<Longrightarrow> xs = ys"
kleing@13863
  1730
  apply (simp add: list_all2_conv_all_nth) 
paulson@14208
  1731
  apply (rule nth_equalityI, blast, simp)
kleing@13863
  1732
  done
kleing@13863
  1733
wenzelm@13142
  1734
lemma take_equalityI: "(\<forall>i. take i xs = take i ys) ==> xs = ys"
nipkow@13145
  1735
-- {* The famous take-lemma. *}
nipkow@13145
  1736
apply (drule_tac x = "max (length xs) (length ys)" in spec)
nipkow@13145
  1737
apply (simp add: le_max_iff_disj take_all)
nipkow@13145
  1738
done
wenzelm@13142
  1739
wenzelm@13142
  1740
nipkow@15302
  1741
lemma take_Cons':
nipkow@15302
  1742
     "take n (x # xs) = (if n = 0 then [] else x # take (n - 1) xs)"
nipkow@15302
  1743
by (cases n) simp_all
nipkow@15302
  1744
nipkow@15302
  1745
lemma drop_Cons':
nipkow@15302
  1746
     "drop n (x # xs) = (if n = 0 then x # xs else drop (n - 1) xs)"
nipkow@15302
  1747
by (cases n) simp_all
nipkow@15302
  1748
nipkow@15302
  1749
lemma nth_Cons': "(x # xs)!n = (if n = 0 then x else xs!(n - 1))"
nipkow@15302
  1750
by (cases n) simp_all
nipkow@15302
  1751
paulson@18622
  1752
lemmas take_Cons_number_of = take_Cons'[of "number_of v",standard]
paulson@18622
  1753
lemmas drop_Cons_number_of = drop_Cons'[of "number_of v",standard]
paulson@18622
  1754
lemmas nth_Cons_number_of = nth_Cons'[of _ _ "number_of v",standard]
paulson@18622
  1755
paulson@18622
  1756
declare take_Cons_number_of [simp] 
paulson@18622
  1757
        drop_Cons_number_of [simp] 
paulson@18622
  1758
        nth_Cons_number_of [simp] 
nipkow@15302
  1759
nipkow@15302
  1760
nipkow@15392
  1761
subsubsection {* @{text "distinct"} and @{text remdups} *}
wenzelm@13142
  1762
wenzelm@13142
  1763
lemma distinct_append [simp]:
nipkow@13145
  1764
"distinct (xs @ ys) = (distinct xs \<and> distinct ys \<and> set xs \<inter> set ys = {})"
nipkow@13145
  1765
by (induct xs) auto
wenzelm@13142
  1766
nipkow@15305
  1767
lemma distinct_rev[simp]: "distinct(rev xs) = distinct xs"
nipkow@15305
  1768
by(induct xs) auto
nipkow@15305
  1769
wenzelm@13142
  1770
lemma set_remdups [simp]: "set (remdups xs) = set xs"
nipkow@13145
  1771
by (induct xs) (auto simp add: insert_absorb)
wenzelm@13142
  1772
wenzelm@13142
  1773
lemma distinct_remdups [iff]: "distinct (remdups xs)"
nipkow@13145
  1774
by (induct xs) auto
wenzelm@13142
  1775
paulson@15072
  1776
lemma remdups_eq_nil_iff [simp]: "(remdups x = []) = (x = [])"
paulson@15251
  1777
  by (induct x, auto) 
paulson@15072
  1778
paulson@15072
  1779
lemma remdups_eq_nil_right_iff [simp]: "([] = remdups x) = (x = [])"
paulson@15251
  1780
  by (induct x, auto)
paulson@15072
  1781
nipkow@15245
  1782
lemma length_remdups_leq[iff]: "length(remdups xs) <= length xs"
nipkow@15245
  1783
by (induct xs) auto
nipkow@15245
  1784
nipkow@15245
  1785
lemma length_remdups_eq[iff]:
nipkow@15245
  1786
  "(length (remdups xs) = length xs) = (remdups xs = xs)"
nipkow@15245
  1787
apply(induct xs)
nipkow@15245
  1788
 apply auto
nipkow@15245
  1789
apply(subgoal_tac "length (remdups xs) <= length xs")
nipkow@15245
  1790
 apply arith
nipkow@15245
  1791
apply(rule length_remdups_leq)
nipkow@15245
  1792
done
nipkow@15245
  1793
nipkow@18490
  1794
nipkow@18490
  1795
lemma distinct_map:
nipkow@18490
  1796
  "distinct(map f xs) = (distinct xs & inj_on f (set xs))"
nipkow@18490
  1797
by (induct xs) auto
nipkow@18490
  1798
nipkow@18490
  1799
wenzelm@13142
  1800
lemma distinct_filter [simp]: "distinct xs ==> distinct (filter P xs)"
nipkow@13145
  1801
by (induct xs) auto
wenzelm@13114
  1802
nipkow@17501
  1803
lemma distinct_upt[simp]: "distinct[i..<j]"
nipkow@17501
  1804
by (induct j) auto
nipkow@17501
  1805
nipkow@17501
  1806
lemma distinct_take[simp]: "\<And>i. distinct xs \<Longrightarrow> distinct (take i xs)"
nipkow@17501
  1807
apply(induct xs)
nipkow@17501
  1808
 apply simp
nipkow@17501
  1809
apply (case_tac i)
nipkow@17501
  1810
 apply simp_all
nipkow@17501
  1811
apply(blast dest:in_set_takeD)
nipkow@17501
  1812
done
nipkow@17501
  1813
nipkow@17501
  1814
lemma distinct_drop[simp]: "\<And>i. distinct xs \<Longrightarrow> distinct (drop i xs)"
nipkow@17501
  1815
apply(induct xs)
nipkow@17501
  1816
 apply simp
nipkow@17501
  1817
apply (case_tac i)
nipkow@17501
  1818
 apply simp_all
nipkow@17501
  1819
done
nipkow@17501
  1820
nipkow@17501
  1821
lemma distinct_list_update:
nipkow@17501
  1822
assumes d: "distinct xs" and a: "a \<notin> set xs - {xs!i}"
nipkow@17501
  1823
shows "distinct (xs[i:=a])"
nipkow@17501
  1824
proof (cases "i < length xs")
nipkow@17501
  1825
  case True
nipkow@17501
  1826
  with a have "a \<notin> set (take i xs @ xs ! i # drop (Suc i) xs) - {xs!i}"
nipkow@17501
  1827
    apply (drule_tac id_take_nth_drop) by simp
nipkow@17501
  1828
  with d True show ?thesis
nipkow@17501
  1829
    apply (simp add: upd_conv_take_nth_drop)
nipkow@17501
  1830
    apply (drule subst [OF id_take_nth_drop]) apply assumption
nipkow@17501
  1831
    apply simp apply (cases "a = xs!i") apply simp by blast
nipkow@17501
  1832
next
nipkow@17501
  1833
  case False with d show ?thesis by auto
nipkow@17501
  1834
qed
nipkow@17501
  1835
nipkow@17501
  1836
nipkow@17501
  1837
text {* It is best to avoid this indexed version of distinct, but
nipkow@17501
  1838
sometimes it is useful. *}
nipkow@17501
  1839
wenzelm@13142
  1840
lemma distinct_conv_nth:
nipkow@17501
  1841
"distinct xs = (\<forall>i < size xs. \<forall>j < size xs. i \<noteq> j --> xs!i \<noteq> xs!j)"
paulson@15251
  1842
apply (induct xs, simp, simp)
paulson@14208
  1843
apply (rule iffI, clarsimp)
nipkow@13145
  1844
 apply (case_tac i)
paulson@14208
  1845
apply (case_tac j, simp)
nipkow@13145
  1846
apply (simp add: set_conv_nth)
nipkow@13145
  1847
 apply (case_tac j)
paulson@14208
  1848
apply (clarsimp simp add: set_conv_nth, simp)
nipkow@13145
  1849
apply (rule conjI)
nipkow@13145
  1850
 apply (clarsimp simp add: set_conv_nth)
nipkow@17501
  1851
 apply (erule_tac x = 0 in allE, simp)
paulson@14208
  1852
 apply (erule_tac x = "Suc i" in allE, simp, clarsimp)
nipkow@17501
  1853
apply (erule_tac x = "Suc i" in allE, simp)
paulson@14208
  1854
apply (erule_tac x = "Suc j" in allE, simp)
nipkow@13145
  1855
done
wenzelm@13114
  1856
nipkow@18490
  1857
lemma nth_eq_iff_index_eq:
nipkow@18490
  1858
 "\<lbrakk> distinct xs; i < length xs; j < length xs \<rbrakk> \<Longrightarrow> (xs!i = xs!j) = (i = j)"
nipkow@18490
  1859
by(auto simp: distinct_conv_nth)
nipkow@18490
  1860
nipkow@15110
  1861
lemma distinct_card: "distinct xs ==> card (set xs) = size xs"
kleing@14388
  1862
  by (induct xs) auto
kleing@14388
  1863
nipkow@15110
  1864
lemma card_distinct: "card (set xs) = size xs ==> distinct xs"
kleing@14388
  1865
proof (induct xs)
kleing@14388
  1866
  case Nil thus ?case by simp
kleing@14388
  1867
next
kleing@14388
  1868
  case (Cons x xs)
kleing@14388
  1869
  show ?case
kleing@14388
  1870
  proof (cases "x \<in> set xs")
kleing@14388
  1871
    case False with Cons show ?thesis by simp
kleing@14388
  1872
  next
kleing@14388
  1873
    case True with Cons.prems
kleing@14388
  1874
    have "card (set xs) = Suc (length xs)" 
kleing@14388
  1875
      by (simp add: card_insert_if split: split_if_asm)
kleing@14388
  1876
    moreover have "card (set xs) \<le> length xs" by (rule card_length)
kleing@14388
  1877
    ultimately have False by simp
kleing@14388
  1878
    thus ?thesis ..
kleing@14388
  1879
  qed
kleing@14388
  1880
qed
kleing@14388
  1881
nipkow@18490
  1882
nipkow@18490
  1883
lemma length_remdups_concat:
nipkow@18490
  1884
 "length(remdups(concat xss)) = card(\<Union>xs \<in> set xss. set xs)"
nipkow@18490
  1885
by(simp add: distinct_card[symmetric])
nipkow@17906
  1886
nipkow@17906
  1887
nipkow@15392
  1888
subsubsection {* @{text remove1} *}
nipkow@15110
  1889
nipkow@18049
  1890
lemma remove1_append:
nipkow@18049
  1891
  "remove1 x (xs @ ys) =
nipkow@18049
  1892
  (if x \<in> set xs then remove1 x xs @ ys else xs @ remove1 x ys)"
nipkow@18049
  1893
by (induct xs) auto
nipkow@18049
  1894
nipkow@15110
  1895
lemma set_remove1_subset: "set(remove1 x xs) <= set xs"
nipkow@15110
  1896
apply(induct xs)
nipkow@15110
  1897
 apply simp
nipkow@15110
  1898
apply simp
nipkow@15110
  1899
apply blast
nipkow@15110
  1900
done
nipkow@15110
  1901
paulson@17724
  1902
lemma set_remove1_eq [simp]: "distinct xs ==> set(remove1 x xs) = set xs - {x}"
nipkow@15110
  1903
apply(induct xs)
nipkow@15110
  1904
 apply simp
nipkow@15110
  1905
apply simp
nipkow@15110
  1906
apply blast
nipkow@15110
  1907
done
nipkow@15110
  1908
nipkow@18049
  1909
lemma remove1_filter_not[simp]:
nipkow@18049
  1910
  "\<not> P x \<Longrightarrow> remove1 x (filter P xs) = filter P xs"
nipkow@18049
  1911
by(induct xs) auto
nipkow@18049
  1912
nipkow@15110
  1913
lemma notin_set_remove1[simp]: "x ~: set xs ==> x ~: set(remove1 y xs)"
nipkow@15110
  1914
apply(insert set_remove1_subset)
nipkow@15110
  1915
apply fast
nipkow@15110
  1916
done
nipkow@15110
  1917
nipkow@15110
  1918
lemma distinct_remove1[simp]: "distinct xs ==> distinct(remove1 x xs)"
nipkow@15110
  1919
by (induct xs) simp_all
nipkow@15110
  1920
wenzelm@13114
  1921
nipkow@15392
  1922
subsubsection {* @{text replicate} *}
wenzelm@13114
  1923
wenzelm@13142
  1924
lemma length_replicate [simp]: "length (replicate n x) = n"
nipkow@13145
  1925
by (induct n) auto
nipkow@13124
  1926
wenzelm@13142
  1927
lemma map_replicate [simp]: "map f (replicate n x) = replicate n (f x)"
nipkow@13145
  1928
by (induct n) auto
wenzelm@13114
  1929
wenzelm@13114
  1930
lemma replicate_app_Cons_same:
nipkow@13145
  1931
"(replicate n x) @ (x # xs) = x # replicate n x @ xs"
nipkow@13145
  1932
by (induct n) auto
wenzelm@13114
  1933
wenzelm@13142
  1934
lemma rev_replicate [simp]: "rev (replicate n x) = replicate n x"
paulson@14208
  1935
apply (induct n, simp)
nipkow@13145
  1936
apply (simp add: replicate_app_Cons_same)
nipkow@13145
  1937
done
wenzelm@13114
  1938
wenzelm@13142
  1939
lemma replicate_add: "replicate (n + m) x = replicate n x @ replicate m x"
nipkow@13145
  1940
by (induct n) auto
wenzelm@13114
  1941
nipkow@16397
  1942
text{* Courtesy of Matthias Daum: *}
nipkow@16397
  1943
lemma append_replicate_commute:
nipkow@16397
  1944
  "replicate n x @ replicate k x = replicate k x @ replicate n x"
nipkow@16397
  1945
apply (simp add: replicate_add [THEN sym])
nipkow@16397
  1946
apply (simp add: add_commute)
nipkow@16397
  1947
done
nipkow@16397
  1948
wenzelm@13142
  1949
lemma hd_replicate [simp]: "n \<noteq> 0 ==> hd (replicate n x) = x"
nipkow@13145
  1950
by (induct n) auto
wenzelm@13114
  1951
wenzelm@13142
  1952
lemma tl_replicate [simp]: "n \<noteq> 0 ==> tl (replicate n x) = replicate (n - 1) x"
nipkow@13145
  1953
by (induct n) auto
wenzelm@13114
  1954
wenzelm@13142
  1955
lemma last_replicate [simp]: "n \<noteq> 0 ==> last (replicate n x) = x"
nipkow@13145
  1956
by (atomize (full), induct n) auto
wenzelm@13114
  1957
wenzelm@13142
  1958
lemma nth_replicate[simp]: "!!i. i < n ==> (replicate n x)!i = x"
paulson@14208
  1959
apply (induct n, simp)
nipkow@13145
  1960
apply (simp add: nth_Cons split: nat.split)
nipkow@13145
  1961
done
wenzelm@13114
  1962
nipkow@16397
  1963
text{* Courtesy of Matthias Daum (2 lemmas): *}
nipkow@16397
  1964
lemma take_replicate[simp]: "take i (replicate k x) = replicate (min i k) x"
nipkow@16397
  1965
apply (case_tac "k \<le> i")
nipkow@16397
  1966
 apply  (simp add: min_def)
nipkow@16397
  1967
apply (drule not_leE)
nipkow@16397
  1968
apply (simp add: min_def)
nipkow@16397
  1969
apply (subgoal_tac "replicate k x = replicate i x @ replicate (k - i) x")
nipkow@16397
  1970
 apply  simp
nipkow@16397
  1971
apply (simp add: replicate_add [symmetric])
nipkow@16397
  1972
done
nipkow@16397
  1973
nipkow@16397
  1974
lemma drop_replicate[simp]: "!!i. drop i (replicate k x) = replicate (k-i) x"
nipkow@16397
  1975
apply (induct k)
nipkow@16397
  1976
 apply simp
nipkow@16397
  1977
apply clarsimp
nipkow@16397
  1978
apply (case_tac i)
nipkow@16397
  1979
 apply simp
nipkow@16397
  1980
apply clarsimp
nipkow@16397
  1981
done
nipkow@16397
  1982
nipkow@16397
  1983
wenzelm@13142
  1984
lemma set_replicate_Suc: "set (replicate (Suc n) x) = {x}"
nipkow@13145
  1985
by (induct n) auto
wenzelm@13114
  1986
wenzelm@13142
  1987
lemma set_replicate [simp]: "n \<noteq> 0 ==> set (replicate n x) = {x}"
nipkow@13145
  1988
by (fast dest!: not0_implies_Suc intro!: set_replicate_Suc)
wenzelm@13114
  1989
wenzelm@13142
  1990
lemma set_replicate_conv_if: "set (replicate n x) = (if n = 0 then {} else {x})"
nipkow@13145
  1991
by auto
wenzelm@13114
  1992
wenzelm@13142
  1993
lemma in_set_replicateD: "x : set (replicate n y) ==> x = y"
nipkow@13145
  1994
by (simp add: set_replicate_conv_if split: split_if_asm)
wenzelm@13114
  1995
wenzelm@13114
  1996
nipkow@15392
  1997
subsubsection{*@{text rotate1} and @{text rotate}*}
nipkow@15302
  1998
nipkow@15302
  1999
lemma rotate_simps[simp]: "rotate1 [] = [] \<and> rotate1 (x#xs) = xs @ [x]"
nipkow@15302
  2000
by(simp add:rotate1_def)
nipkow@15302
  2001
nipkow@15302
  2002
lemma rotate0[simp]: "rotate 0 = id"
nipkow@15302
  2003
by(simp add:rotate_def)
nipkow@15302
  2004
nipkow@15302
  2005
lemma rotate_Suc[simp]: "rotate (Suc n) xs = rotate1(rotate n xs)"
nipkow@15302
  2006
by(simp add:rotate_def)
nipkow@15302
  2007
nipkow@15302
  2008
lemma rotate_add:
nipkow@15302
  2009
  "rotate (m+n) = rotate m o rotate n"
nipkow@15302
  2010
by(simp add:rotate_def funpow_add)
nipkow@15302
  2011
nipkow@15302
  2012
lemma rotate_rotate: "rotate m (rotate n xs) = rotate (m+n) xs"
nipkow@15302
  2013
by(simp add:rotate_add)
nipkow@15302
  2014
nipkow@18049
  2015
lemma rotate1_rotate_swap: "rotate1 (rotate n xs) = rotate n (rotate1 xs)"
nipkow@18049
  2016
by(simp add:rotate_def funpow_swap1)
nipkow@18049
  2017
nipkow@15302
  2018
lemma rotate1_length01[simp]: "length xs <= 1 \<Longrightarrow> rotate1 xs = xs"
nipkow@15302
  2019
by(cases xs) simp_all
nipkow@15302
  2020
nipkow@15302
  2021
lemma rotate_length01[simp]: "length xs <= 1 \<Longrightarrow> rotate n xs = xs"
nipkow@15302
  2022
apply(induct n)
nipkow@15302
  2023
 apply simp
nipkow@15302
  2024
apply (simp add:rotate_def)
nipkow@13145
  2025
done
wenzelm@13114
  2026
nipkow@15302
  2027
lemma rotate1_hd_tl: "xs \<noteq> [] \<Longrightarrow> rotate1 xs = tl xs @ [hd xs]"
nipkow@15302
  2028
by(simp add:rotate1_def split:list.split)
nipkow@15302
  2029
nipkow@15302
  2030
lemma rotate_drop_take:
nipkow@15302
  2031
  "rotate n xs = drop (n mod length xs) xs @ take (n mod length xs) xs"
nipkow@15302
  2032
apply(induct n)
nipkow@15302
  2033
 apply simp
nipkow@15302
  2034
apply(simp add:rotate_def)
nipkow@15302
  2035
apply(cases "xs = []")
nipkow@15302
  2036
 apply (simp)
nipkow@15302
  2037
apply(case_tac "n mod length xs = 0")
nipkow@15302
  2038
 apply(simp add:mod_Suc)
nipkow@15302
  2039
 apply(simp add: rotate1_hd_tl drop_Suc take_Suc)
nipkow@15302
  2040
apply(simp add:mod_Suc rotate1_hd_tl drop_Suc[symmetric] drop_tl[symmetric]
nipkow@15302
  2041
                take_hd_drop linorder_not_le)
nipkow@13145
  2042
done
wenzelm@13114
  2043
nipkow@15302
  2044
lemma rotate_conv_mod: "rotate n xs = rotate (n mod length xs) xs"
nipkow@15302
  2045
by(simp add:rotate_drop_take)
nipkow@15302
  2046
nipkow@15302
  2047
lemma rotate_id[simp]: "n mod length xs = 0 \<Longrightarrow> rotate n xs = xs"
nipkow@15302
  2048
by(simp add:rotate_drop_take)
nipkow@15302
  2049
nipkow@15302
  2050
lemma length_rotate1[simp]: "length(rotate1 xs) = length xs"
nipkow@15302
  2051
by(simp add:rotate1_def split:list.split)
nipkow@15302
  2052
nipkow@15302
  2053
lemma length_rotate[simp]: "!!xs. length(rotate n xs) = length xs"
nipkow@15302
  2054
by (induct n) (simp_all add:rotate_def)
nipkow@15302
  2055
nipkow@15302
  2056
lemma distinct1_rotate[simp]: "distinct(rotate1 xs) = distinct xs"
nipkow@15302
  2057
by(simp add:rotate1_def split:list.split) blast
nipkow@15302
  2058
nipkow@15302
  2059
lemma distinct_rotate[simp]: "distinct(rotate n xs) = distinct xs"
nipkow@15302
  2060
by (induct n) (simp_all add:rotate_def)
nipkow@15302
  2061
nipkow@15302
  2062
lemma rotate_map: "rotate n (map f xs) = map f (rotate n xs)"
nipkow@15302
  2063
by(simp add:rotate_drop_take take_map drop_map)
nipkow@15302
  2064
nipkow@15302
  2065
lemma set_rotate1[simp]: "set(rotate1 xs) = set xs"
nipkow@15302
  2066
by(simp add:rotate1_def split:list.split)
nipkow@15302
  2067
nipkow@15302
  2068
lemma set_rotate[simp]: "set(rotate n xs) = set xs"
nipkow@15302
  2069
by (induct n) (simp_all add:rotate_def)
nipkow@15302
  2070
nipkow@15302
  2071
lemma rotate1_is_Nil_conv[simp]: "(rotate1 xs = []) = (xs = [])"
nipkow@15302
  2072
by(simp add:rotate1_def split:list.split)
nipkow@15302
  2073
nipkow@15302
  2074
lemma rotate_is_Nil_conv[simp]: "(rotate n xs = []) = (xs = [])"
nipkow@15302
  2075
by (induct n) (simp_all add:rotate_def)
wenzelm@13114
  2076
nipkow@15439
  2077
lemma rotate_rev:
nipkow@15439
  2078
  "rotate n (rev xs) = rev(rotate (length xs - (n mod length xs)) xs)"
nipkow@15439
  2079
apply(simp add:rotate_drop_take rev_drop rev_take)
nipkow@15439
  2080
apply(cases "length xs = 0")
nipkow@15439
  2081
 apply simp
nipkow@15439
  2082
apply(cases "n mod length xs = 0")
nipkow@15439
  2083
 apply simp
nipkow@15439
  2084
apply(simp add:rotate_drop_take rev_drop rev_take)
nipkow@15439
  2085
done
nipkow@15439
  2086
nipkow@18423
  2087
lemma hd_rotate_conv_nth: "xs \<noteq> [] \<Longrightarrow> hd(rotate n xs) = xs!(n mod length xs)"
nipkow@18423
  2088
apply(simp add:rotate_drop_take hd_append hd_drop_conv_nth hd_conv_nth)
nipkow@18423
  2089
apply(subgoal_tac "length xs \<noteq> 0")
nipkow@18423
  2090
 prefer 2 apply simp
nipkow@18423
  2091
using mod_less_divisor[of "length xs" n] by arith
nipkow@18423
  2092
wenzelm@13114
  2093
nipkow@15392
  2094
subsubsection {* @{text sublist} --- a generalization of @{text nth} to sets *}
wenzelm@13114
  2095
wenzelm@13142
  2096
lemma sublist_empty [simp]: "sublist xs {} = []"
nipkow@13145
  2097
by (auto simp add: sublist_def)
wenzelm@13114
  2098
wenzelm@13142
  2099
lemma sublist_nil [simp]: "sublist [] A = []"
nipkow@13145
  2100
by (auto simp add: sublist_def)
wenzelm@13114
  2101
nipkow@15281
  2102
lemma length_sublist:
nipkow@15281
  2103
  "length(sublist xs I) = card{i. i < length xs \<and> i : I}"
nipkow@15281
  2104
by(simp add: sublist_def length_filter_conv_card cong:conj_cong)
nipkow@15281
  2105
nipkow@15281
  2106
lemma sublist_shift_lemma_Suc:
nipkow@15281
  2107
  "!!is. map fst (filter (%p. P(Suc(snd p))) (zip xs is)) =
nipkow@15281
  2108
         map fst (filter (%p. P(snd p)) (zip xs (map Suc is)))"
nipkow@15281
  2109
apply(induct xs)
nipkow@15281
  2110
 apply simp
nipkow@15281
  2111
apply (case_tac "is")
nipkow@15281
  2112
 apply simp
nipkow@15281
  2113
apply simp
nipkow@15281
  2114
done
nipkow@15281
  2115
wenzelm@13114
  2116
lemma sublist_shift_lemma:
nipkow@15425
  2117
     "map fst [p:zip xs [i..<i + length xs] . snd p : A] =
nipkow@15425
  2118
      map fst [p:zip xs [0..<length xs] . snd p + i : A]"
nipkow@13145
  2119
by (induct xs rule: rev_induct) (simp_all add: add_commute)
wenzelm@13114
  2120
wenzelm@13114
  2121
lemma sublist_append:
paulson@15168
  2122
     "sublist (l @ l') A = sublist l A @ sublist l' {j. j + length l : A}"
nipkow@13145
  2123
apply (unfold sublist_def)
paulson@14208
  2124
apply (induct l' rule: rev_induct, simp)
nipkow@13145
  2125
apply (simp add: upt_add_eq_append[of 0] zip_append sublist_shift_lemma)
nipkow@13145
  2126
apply (simp add: add_commute)
nipkow@13145
  2127
done
wenzelm@13114
  2128
wenzelm@13114
  2129
lemma sublist_Cons:
nipkow@13145
  2130
"sublist (x # l) A = (if 0:A then [x] else []) @ sublist l {j. Suc j : A}"
nipkow@13145
  2131
apply (induct l rule: rev_induct)
nipkow@13145
  2132
 apply (simp add: sublist_def)
nipkow@13145
  2133
apply (simp del: append_Cons add: append_Cons[symmetric] sublist_append)
nipkow@13145
  2134
done
wenzelm@13114
  2135
nipkow@15281
  2136
lemma set_sublist: "!!I. set(sublist xs I) = {xs!i|i. i<size xs \<and> i \<in> I}"
nipkow@15281
  2137
apply(induct xs)
nipkow@15281
  2138
 apply simp
nipkow@15281
  2139
apply(auto simp add:sublist_Cons nth_Cons split:nat.split elim: lessE)
nipkow@15281
  2140
 apply(erule lessE)
nipkow@15281
  2141
  apply auto
nipkow@15281
  2142
apply(erule lessE)
nipkow@15281
  2143
apply auto
nipkow@15281
  2144
done
nipkow@15281
  2145
nipkow@15281
  2146
lemma set_sublist_subset: "set(sublist xs I) \<subseteq> set xs"
nipkow@15281
  2147
by(auto simp add:set_sublist)
nipkow@15281
  2148
nipkow@15281
  2149
lemma notin_set_sublistI[simp]: "x \<notin> set xs \<Longrightarrow> x \<notin> set(sublist xs I)"
nipkow@15281
  2150
by(auto simp add:set_sublist)
nipkow@15281
  2151
nipkow@15281
  2152
lemma in_set_sublistD: "x \<in> set(sublist xs I) \<Longrightarrow> x \<in> set xs"
nipkow@15281
  2153
by(auto simp add:set_sublist)
nipkow@15281
  2154
wenzelm@13142
  2155
lemma sublist_singleton [simp]: "sublist [x] A = (if 0 : A then [x] else [])"
nipkow@13145
  2156
by (simp add: sublist_Cons)
wenzelm@13114
  2157
nipkow@15281
  2158
nipkow@15281
  2159
lemma distinct_sublistI[simp]: "!!I. distinct xs \<Longrightarrow> distinct(sublist xs I)"
nipkow@15281
  2160
apply(induct xs)
nipkow@15281
  2161
 apply simp
nipkow@15281
  2162
apply(auto simp add:sublist_Cons)
nipkow@15281
  2163
done
nipkow@15281
  2164
nipkow@15281
  2165
nipkow@15045
  2166
lemma sublist_upt_eq_take [simp]: "sublist l {..<n} = take n l"
paulson@14208
  2167
apply (induct l rule: rev_induct, simp)
nipkow@13145
  2168
apply (simp split: nat_diff_split add: sublist_append)
nipkow@13145
  2169
done
wenzelm@13114
  2170
nipkow@17501
  2171
lemma filter_in_sublist: "\<And>s. distinct xs \<Longrightarrow>
nipkow@17501
  2172
  filter (%x. x \<in> set(sublist xs s)) xs = sublist xs s"
nipkow@17501
  2173
proof (induct xs)
nipkow@17501
  2174
  case Nil thus ?case by simp
nipkow@17501
  2175
next
nipkow@17501
  2176
  case (Cons a xs)
nipkow@17501
  2177
  moreover hence "!x. x: set xs \<longrightarrow> x \<noteq> a" by auto
nipkow@17501
  2178
  ultimately show ?case by(simp add: sublist_Cons cong:filter_cong)
nipkow@17501
  2179
qed
nipkow@17501
  2180
wenzelm@13114
  2181
nipkow@19390
  2182
subsubsection {* @{const splice} *}
nipkow@19390
  2183
haftmann@19607
  2184
lemma splice_Nil2 [simp, code]:
nipkow@19390
  2185
 "splice xs [] = xs"
nipkow@19390
  2186
by (cases xs) simp_all
nipkow@19390
  2187
haftmann@19607
  2188
lemma splice_Cons_Cons [simp, code]:
nipkow@19390
  2189
 "splice (x#xs) (y#ys) = x # y # splice xs ys"
nipkow@19390
  2190
by simp
nipkow@19390
  2191
haftmann@19607
  2192
declare splice.simps(2) [simp del, code del]
nipkow@19390
  2193
nipkow@15392
  2194
subsubsection{*Sets of Lists*}
nipkow@15392
  2195
nipkow@15392
  2196
subsubsection {* @{text lists}: the list-forming operator over sets *}
nipkow@15302
  2197
nipkow@15302
  2198
consts lists :: "'a set => 'a list set"
nipkow@15302
  2199
inductive "lists A"
nipkow@15302
  2200
 intros
nipkow@15302
  2201
  Nil [intro!]: "[]: lists A"
nipkow@15302
  2202
  Cons [intro!]: "[| a: A;l: lists A|] ==> a#l : lists A"
nipkow@15302
  2203
nipkow@15302
  2204
inductive_cases listsE [elim!]: "x#l : lists A"
nipkow@15302
  2205
nipkow@15302
  2206
lemma lists_mono [mono]: "A \<subseteq> B ==> lists A \<subseteq> lists B"
nipkow@15302
  2207
by (unfold lists.defs) (blast intro!: lfp_mono)
nipkow@15302
  2208
nipkow@15302
  2209
lemma lists_IntI:
nipkow@15302
  2210
  assumes l: "l: lists A" shows "l: lists B ==> l: lists (A Int B)" using l
nipkow@15302
  2211
  by induct blast+
nipkow@15302
  2212
nipkow@15302
  2213
lemma lists_Int_eq [simp]: "lists (A \<inter> B) = lists A \<inter> lists B"
nipkow@15302
  2214
proof (rule mono_Int [THEN equalityI])
nipkow@15302
  2215
  show "mono lists" by (simp add: mono_def lists_mono)
nipkow@15302
  2216
  show "lists A \<inter> lists B \<subseteq> lists (A \<inter> B)" by (blast intro: lists_IntI)
kleing@14388
  2217
qed
kleing@14388
  2218
nipkow@15302
  2219
lemma append_in_lists_conv [iff]:
nipkow@15302
  2220
     "(xs @ ys : lists A) = (xs : lists A \<and> ys : lists A)"
nipkow@15302
  2221
by (induct xs) auto
nipkow@15302
  2222
nipkow@15302
  2223
lemma in_lists_conv_set: "(xs : lists A) = (\<forall>x \<in> set xs. x : A)"
nipkow@15302
  2224
-- {* eliminate @{text lists} in favour of @{text set} *}
nipkow@15302
  2225
by (induct xs) auto
nipkow@15302
  2226
nipkow@15302
  2227
lemma in_listsD [dest!]: "xs \<in> lists A ==> \<forall>x\<in>set xs. x \<in> A"
nipkow@15302
  2228
by (rule in_lists_conv_set [THEN iffD1])
nipkow@15302
  2229
nipkow@15302
  2230
lemma in_listsI [intro!]: "\<forall>x\<in>set xs. x \<in> A ==> xs \<in> lists A"
nipkow@15302
  2231
by (rule in_lists_conv_set [THEN iffD2])
nipkow@15302
  2232
nipkow@15302
  2233
lemma lists_UNIV [simp]: "lists UNIV = UNIV"
nipkow@15302
  2234
by auto
nipkow@15302
  2235
nipkow@17086
  2236
subsubsection {* For efficiency *}
nipkow@17086
  2237
nipkow@17086
  2238
text{* Only use @{text mem} for generating executable code.  Otherwise
nipkow@17086
  2239
use @{prop"x : set xs"} instead --- it is much easier to reason about.
nipkow@17086
  2240
The same is true for @{const list_all} and @{const list_ex}: write
nipkow@17086
  2241
@{text"\<forall>x\<in>set xs"} and @{text"\<exists>x\<in>set xs"} instead because the HOL
haftmann@19817
  2242
quantifiers are aleady known to the automatic provers. In fact,
haftmann@19817
  2243
the declarations in the code subsection make sure that @{text"\<in>"}, @{text"\<forall>x\<in>set xs"}
nipkow@17090
  2244
and @{text"\<exists>x\<in>set xs"} are implemented efficiently.
nipkow@17086
  2245
nipkow@17086
  2246
The functions @{const itrev}, @{const filtermap} and @{const
nipkow@17086
  2247
map_filter} are just there to generate efficient code. Do not use them
nipkow@17086
  2248
for modelling and proving. *}
nipkow@17086
  2249
nipkow@17086
  2250
lemma mem_iff: "(x mem xs) = (x : set xs)"
nipkow@17086
  2251
by (induct xs) auto
nipkow@17086
  2252
nipkow@17086
  2253
lemma list_inter_conv: "set(list_inter xs ys) = set xs \<inter> set ys"
nipkow@17086
  2254
by (induct xs) auto
nipkow@17086
  2255
nipkow@17086
  2256
lemma list_all_iff: "list_all P xs = (\<forall>x \<in> set xs. P x)"
nipkow@17086
  2257
by (induct xs) auto
nipkow@17086
  2258
nipkow@17086
  2259
lemma list_all_append [simp]:
nipkow@17086
  2260
"list_all P (xs @ ys) = (list_all P xs \<and> list_all P ys)"
nipkow@17086
  2261
by (induct xs) auto
nipkow@17086
  2262
nipkow@17086
  2263
lemma list_all_rev [simp]: "list_all P (rev xs) = list_all P xs"
nipkow@17086
  2264
by (simp add: list_all_iff)
nipkow@17086
  2265
nipkow@17086
  2266
lemma list_ex_iff: "list_ex P xs = (\<exists>x \<in> set xs. P x)"
nipkow@17086
  2267
by (induct xs) simp_all
nipkow@17086
  2268
nipkow@17086
  2269
lemma itrev[simp]: "ALL ys. itrev xs ys = rev xs @ ys"
nipkow@17086
  2270
by (induct xs) simp_all
nipkow@17086
  2271
nipkow@17086
  2272
lemma filtermap_conv:
paulson@18447
  2273
     "filtermap f xs = map (%x. the(f x)) (filter (%x. f x \<noteq> None) xs)"
paulson@18447
  2274
  by (induct xs) (simp_all split: option.split) 
nipkow@17086
  2275
nipkow@17086
  2276
lemma map_filter_conv[simp]: "map_filter f P xs = map f (filter P xs)"
nipkow@17086
  2277
by (induct xs) auto
nipkow@17086
  2278
nipkow@17086
  2279
nipkow@17086
  2280
subsubsection {* Code generation *}
nipkow@17086
  2281
nipkow@17086
  2282
text{* Defaults for generating efficient code for some standard functions. *}
nipkow@17086
  2283
nipkow@17090
  2284
lemmas in_set_code[code unfold] = mem_iff[symmetric, THEN eq_reflection]
nipkow@17090
  2285
nipkow@17090
  2286
lemma rev_code[code unfold]: "rev xs == itrev xs []"
nipkow@17086
  2287
by simp
nipkow@17086
  2288
nipkow@17090
  2289
lemma distinct_Cons_mem[code]: "distinct (x#xs) = (~(x mem xs) \<and> distinct xs)"
nipkow@17086
  2290
by (simp add:mem_iff)
nipkow@17086
  2291
nipkow@17090
  2292
lemma remdups_Cons_mem[code]:
nipkow@17086
  2293
 "remdups (x#xs) = (if x mem xs then remdups xs else x # remdups xs)"
nipkow@17086
  2294
by (simp add:mem_iff)
nipkow@17086
  2295
nipkow@17090
  2296
lemma list_inter_Cons_mem[code]:  "list_inter (a#as) bs =
nipkow@17086
  2297
  (if a mem bs then a#(list_inter as bs) else list_inter as bs)"
nipkow@17086
  2298
by(simp add:mem_iff)
nipkow@17086
  2299
nipkow@17090
  2300
text{* For implementing bounded quantifiers over lists by
nipkow@17090
  2301
@{const list_ex}/@{const list_all}: *}
nipkow@17090
  2302
nipkow@17090
  2303
lemmas list_bex_code[code unfold] = list_ex_iff[symmetric, THEN eq_reflection]
nipkow@17090
  2304
lemmas list_ball_code[code unfold] = list_all_iff[symmetric, THEN eq_reflection]
nipkow@17086
  2305
nipkow@17086
  2306
nipkow@17086
  2307
subsubsection{* Inductive definition for membership *}
nipkow@17086
  2308
nipkow@17086
  2309
consts ListMem :: "('a \<times> 'a list)set"
nipkow@17086
  2310
inductive ListMem
nipkow@17086
  2311
intros
nipkow@17086
  2312
 elem:  "(x,x#xs) \<in> ListMem"
nipkow@17086
  2313
 insert:  "(x,xs) \<in> ListMem \<Longrightarrow> (x,y#xs) \<in> ListMem"
nipkow@17086
  2314
nipkow@17086
  2315
lemma ListMem_iff: "((x,xs) \<in> ListMem) = (x \<in> set xs)"
nipkow@17086
  2316
apply (rule iffI)
nipkow@17086
  2317
 apply (induct set: ListMem)
nipkow@17086
  2318
  apply auto
nipkow@17086
  2319
apply (induct xs)
nipkow@17086
  2320
 apply (auto intro: ListMem.intros)
nipkow@17086
  2321
done
nipkow@17086
  2322
nipkow@17086
  2323
nipkow@17086
  2324
nipkow@15392
  2325
subsubsection{*Lists as Cartesian products*}
nipkow@15302
  2326
nipkow@15302
  2327
text{*@{text"set_Cons A Xs"}: the set of lists with head drawn from
nipkow@15302
  2328
@{term A} and tail drawn from @{term Xs}.*}
nipkow@15302
  2329
nipkow@15302
  2330
constdefs
nipkow@15302
  2331
  set_Cons :: "'a set \<Rightarrow> 'a list set \<Rightarrow> 'a list set"
nipkow@15302
  2332
  "set_Cons A XS == {z. \<exists>x xs. z = x#xs & x \<in> A & xs \<in> XS}"
nipkow@15302
  2333
paulson@17724
  2334
lemma set_Cons_sing_Nil [simp]: "set_Cons A {[]} = (%x. [x])`A"
nipkow@15302
  2335
by (auto simp add: set_Cons_def)
nipkow@15302
  2336
nipkow@15302
  2337
text{*Yields the set of lists, all of the same length as the argument and
nipkow@15302
  2338
with elements drawn from the corresponding element of the argument.*}
nipkow@15302
  2339
nipkow@15302
  2340
consts  listset :: "'a set list \<Rightarrow> 'a list set"
nipkow@15302
  2341
primrec
nipkow@15302
  2342
   "listset []    = {[]}"
nipkow@15302
  2343
   "listset(A#As) = set_Cons A (listset As)"
nipkow@15302
  2344
nipkow@15302
  2345
paulson@15656
  2346
subsection{*Relations on Lists*}
paulson@15656
  2347
paulson@15656
  2348
subsubsection {* Length Lexicographic Ordering *}
paulson@15656
  2349
paulson@15656
  2350
text{*These orderings preserve well-foundedness: shorter lists 
paulson@15656
  2351
  precede longer lists. These ordering are not used in dictionaries.*}
paulson@15656
  2352
paulson@15656
  2353
consts lexn :: "('a * 'a)set => nat => ('a list * 'a list)set"
paulson@15656
  2354
        --{*The lexicographic ordering for lists of the specified length*}
nipkow@15302
  2355
primrec
paulson@15656
  2356
  "lexn r 0 = {}"
paulson@15656
  2357
  "lexn r (Suc n) =
paulson@15656
  2358
    (prod_fun (%(x,xs). x#xs) (%(x,xs). x#xs) ` (r <*lex*> lexn r n)) Int
paulson@15656
  2359
    {(xs,ys). length xs = Suc n \<and> length ys = Suc n}"
nipkow@15302
  2360
nipkow@15302
  2361
constdefs
paulson@15656
  2362
  lex :: "('a \<times> 'a) set => ('a list \<times> 'a list) set"
paulson@15656
  2363
    "lex r == \<Union>n. lexn r n"
paulson@15656
  2364
        --{*Holds only between lists of the same length*}
paulson@15656
  2365
nipkow@15693
  2366
  lenlex :: "('a \<times> 'a) set => ('a list \<times> 'a list) set"
nipkow@15693
  2367
    "lenlex r == inv_image (less_than <*lex*> lex r) (%xs. (length xs, xs))"
paulson@15656
  2368
        --{*Compares lists by their length and then lexicographically*}
nipkow@15302
  2369
nipkow@15302
  2370
nipkow@15302
  2371
lemma wf_lexn: "wf r ==> wf (lexn r n)"
nipkow@15302
  2372
apply (induct n, simp, simp)
nipkow@15302
  2373
apply(rule wf_subset)
nipkow@15302
  2374
 prefer 2 apply (rule Int_lower1)
nipkow@15302
  2375
apply(rule wf_prod_fun_image)
nipkow@15302
  2376
 prefer 2 apply (rule inj_onI, auto)
nipkow@15302
  2377
done
nipkow@15302
  2378
nipkow@15302
  2379
lemma lexn_length:
nipkow@15302
  2380
     "!!xs ys. (xs, ys) : lexn r n ==> length xs = n \<and> length ys = n"
nipkow@15302
  2381
by (induct n) auto
nipkow@15302
  2382
nipkow@15302
  2383
lemma wf_lex [intro!]: "wf r ==> wf (lex r)"
nipkow@15302
  2384
apply (unfold lex_def)
nipkow@15302
  2385
apply (rule wf_UN)
nipkow@15302
  2386
apply (blast intro: wf_lexn, clarify)
nipkow@15302
  2387
apply (rename_tac m n)
nipkow@15302
  2388
apply (subgoal_tac "m \<noteq> n")
nipkow@15302
  2389
 prefer 2 apply blast
nipkow@15302
  2390
apply (blast dest: lexn_length not_sym)
nipkow@15302
  2391
done
nipkow@15302
  2392
nipkow@15302
  2393
lemma lexn_conv:
paulson@15656
  2394
  "lexn r n =
paulson@15656
  2395
    {(xs,ys). length xs = n \<and> length ys = n \<and>
paulson@15656
  2396
    (\<exists>xys x y xs' ys'. xs= xys @ x#xs' \<and> ys= xys @ y # ys' \<and> (x, y):r)}"
nipkow@18423
  2397
apply (induct n, simp)
nipkow@15302
  2398
apply (simp add: image_Collect lex_prod_def, safe, blast)
nipkow@15302
  2399
 apply (rule_tac x = "ab # xys" in exI, simp)
nipkow@15302
  2400
apply (case_tac xys, simp_all, blast)
nipkow@15302
  2401
done
nipkow@15302
  2402
nipkow@15302
  2403
lemma lex_conv:
paulson@15656
  2404
  "lex r =
paulson@15656
  2405
    {(xs,ys). length xs = length ys \<and>
paulson@15656
  2406
    (\<exists>xys x y xs' ys'. xs = xys @ x # xs' \<and> ys = xys @ y # ys' \<and> (x, y):r)}"
nipkow@15302
  2407
by (force simp add: lex_def lexn_conv)
nipkow@15302
  2408
nipkow@15693
  2409
lemma wf_lenlex [intro!]: "wf r ==> wf (lenlex r)"
nipkow@15693
  2410
by (unfold lenlex_def) blast
nipkow@15693
  2411
nipkow@15693
  2412
lemma lenlex_conv:
nipkow@15693
  2413
    "lenlex r = {(xs,ys). length xs < length ys |
paulson@15656
  2414
                 length xs = length ys \<and> (xs, ys) : lex r}"
nipkow@19623
  2415
by (simp add: lenlex_def diag_def lex_prod_def inv_image_def)
nipkow@15302
  2416
nipkow@15302
  2417
lemma Nil_notin_lex [iff]: "([], ys) \<notin> lex r"
nipkow@15302
  2418
by (simp add: lex_conv)
nipkow@15302
  2419
nipkow@15302
  2420
lemma Nil2_notin_lex [iff]: "(xs, []) \<notin> lex r"
nipkow@15302
  2421
by (simp add:lex_conv)
nipkow@15302
  2422
paulson@18447
  2423
lemma Cons_in_lex [simp]:
paulson@15656
  2424
    "((x # xs, y # ys) : lex r) =
paulson@15656
  2425
      ((x, y) : r \<and> length xs = length ys | x = y \<and> (xs, ys) : lex r)"
nipkow@15302
  2426
apply (simp add: lex_conv)
nipkow@15302
  2427
apply (rule iffI)
nipkow@15302
  2428
 prefer 2 apply (blast intro: Cons_eq_appendI, clarify)
nipkow@15302
  2429
apply (case_tac xys, simp, simp)
nipkow@15302
  2430
apply blast
nipkow@15302
  2431
done
nipkow@15302
  2432
nipkow@15302
  2433
paulson@15656
  2434
subsubsection {* Lexicographic Ordering *}
paulson@15656
  2435
paulson@15656
  2436
text {* Classical lexicographic ordering on lists, ie. "a" < "ab" < "b".
paulson@15656
  2437
    This ordering does \emph{not} preserve well-foundedness.
nipkow@17090
  2438
     Author: N. Voelker, March 2005. *} 
paulson@15656
  2439
paulson@15656
  2440
constdefs 
paulson@15656
  2441
  lexord :: "('a * 'a)set \<Rightarrow> ('a list * 'a list) set" 
paulson@15656
  2442
  "lexord  r == {(x,y). \<exists> a v. y = x @ a # v \<or> 
paulson@15656
  2443
            (\<exists> u a b v w. (a,b) \<in> r \<and> x = u @ (a # v) \<and> y = u @ (b # w))}"
paulson@15656
  2444
paulson@15656
  2445
lemma lexord_Nil_left[simp]:  "([],y) \<in> lexord r = (\<exists> a x. y = a # x)"
paulson@15656
  2446
  by (unfold lexord_def, induct_tac y, auto) 
paulson@15656
  2447
paulson@15656
  2448
lemma lexord_Nil_right[simp]: "(x,[]) \<notin> lexord r"
paulson@15656
  2449
  by (unfold lexord_def, induct_tac x, auto)
paulson@15656
  2450
paulson@15656
  2451
lemma lexord_cons_cons[simp]:
paulson@15656
  2452
     "((a # x, b # y) \<in> lexord r) = ((a,b)\<in> r | (a = b & (x,y)\<in> lexord r))"
paulson@15656
  2453
  apply (unfold lexord_def, safe, simp_all)
paulson@15656
  2454
  apply (case_tac u, simp, simp)
paulson@15656
  2455
  apply (case_tac u, simp, clarsimp, blast, blast, clarsimp)
paulson@15656
  2456
  apply (erule_tac x="b # u" in allE)
paulson@15656
  2457
  by force
paulson@15656
  2458
paulson@15656
  2459
lemmas lexord_simps = lexord_Nil_left lexord_Nil_right lexord_cons_cons
paulson@15656
  2460
paulson@15656
  2461
lemma lexord_append_rightI: "\<exists> b z. y = b # z \<Longrightarrow> (x, x @ y) \<in> lexord r"
paulson@15656
  2462
  by (induct_tac x, auto)  
paulson@15656
  2463
paulson@15656
  2464
lemma lexord_append_left_rightI:
paulson@15656
  2465
     "(a,b) \<in> r \<Longrightarrow> (u @ a # x, u @ b # y) \<in> lexord r"
paulson@15656
  2466
  by (induct_tac u, auto)
paulson@15656
  2467
paulson@15656
  2468
lemma lexord_append_leftI: " (u,v) \<in> lexord r \<Longrightarrow> (x @ u, x @ v) \<in> lexord r"
paulson@15656
  2469
  by (induct x, auto)
paulson@15656
  2470
paulson@15656
  2471
lemma lexord_append_leftD:
paulson@15656
  2472
     "\<lbrakk> (x @ u, x @ v) \<in> lexord r; (! a. (a,a) \<notin> r) \<rbrakk> \<Longrightarrow> (u,v) \<in> lexord r"
paulson@15656
  2473
  by (erule rev_mp, induct_tac x, auto)
paulson@15656
  2474
paulson@15656
  2475
lemma lexord_take_index_conv: 
paulson@15656
  2476
   "((x,y) : lexord r) = 
paulson@15656
  2477
    ((length x < length y \<and> take (length x) y = x) \<or> 
paulson@15656
  2478
     (\<exists>i. i < min(length x)(length y) & take i x = take i y & (x!i,y!i) \<in> r))"
paulson@15656
  2479
  apply (unfold lexord_def Let_def, clarsimp) 
paulson@15656
  2480
  apply (rule_tac f = "(% a b. a \<or> b)" in arg_cong2)
paulson@15656
  2481
  apply auto 
paulson@15656
  2482
  apply (rule_tac x="hd (drop (length x) y)" in exI)
paulson@15656
  2483
  apply (rule_tac x="tl (drop (length x) y)" in exI)
paulson@15656
  2484
  apply (erule subst, simp add: min_def) 
paulson@15656
  2485
  apply (rule_tac x ="length u" in exI, simp) 
paulson@15656
  2486
  apply (rule_tac x ="take i x" in exI) 
paulson@15656
  2487
  apply (rule_tac x ="x ! i" in exI) 
paulson@15656
  2488
  apply (rule_tac x ="y ! i" in exI, safe) 
paulson@15656
  2489
  apply (rule_tac x="drop (Suc i) x" in exI)
paulson@15656
  2490
  apply (drule sym, simp add: drop_Suc_conv_tl) 
paulson@15656
  2491
  apply (rule_tac x="drop (Suc i) y" in exI)
paulson@15656
  2492
  by (simp add: drop_Suc_conv_tl) 
paulson@15656
  2493
paulson@15656
  2494
-- {* lexord is extension of partial ordering List.lex *} 
paulson@15656
  2495
lemma lexord_lex: " (x,y) \<in> lex r = ((x,y) \<in> lexord r \<and> length x = length y)"
paulson@15656
  2496
  apply (rule_tac x = y in spec) 
paulson@15656
  2497
  apply (induct_tac x, clarsimp) 
paulson@15656
  2498
  by (clarify, case_tac x, simp, force)
paulson@15656
  2499
paulson@15656
  2500
lemma lexord_irreflexive: "(! x. (x,x) \<notin> r) \<Longrightarrow> (y,y) \<notin> lexord r"
paulson@15656
  2501
  by (induct y, auto)
paulson@15656
  2502
paulson@15656
  2503
lemma lexord_trans: 
paulson@15656
  2504
    "\<lbrakk> (x, y) \<in> lexord r; (y, z) \<in> lexord r; trans r \<rbrakk> \<Longrightarrow> (x, z) \<in> lexord r"
paulson@15656
  2505
   apply (erule rev_mp)+
paulson@15656
  2506
   apply (rule_tac x = x in spec) 
paulson@15656
  2507
  apply (rule_tac x = z in spec) 
paulson@15656
  2508
  apply ( induct_tac y, simp, clarify)
paulson@15656
  2509
  apply (case_tac xa, erule ssubst) 
paulson@15656
  2510
  apply (erule allE, erule allE) -- {* avoid simp recursion *} 
paulson@15656
  2511
  apply (case_tac x, simp, simp) 
paulson@15656
  2512
  apply (case_tac x, erule allE, erule allE, simp) 
paulson@15656
  2513
  apply (erule_tac x = listb in allE) 
paulson@15656
  2514
  apply (erule_tac x = lista in allE, simp)
paulson@15656
  2515
  apply (unfold trans_def)
paulson@15656
  2516
  by blast
paulson@15656
  2517
paulson@15656
  2518
lemma lexord_transI:  "trans r \<Longrightarrow> trans (lexord r)"
paulson@15656
  2519
  by (rule transI, drule lexord_trans, blast) 
paulson@15656
  2520
paulson@15656
  2521
lemma lexord_linear: "(! a b. (a,b)\<in> r | a = b | (b,a) \<in> r) \<Longrightarrow> (x,y) : lexord r | x = y | (y,x) : lexord r"
paulson@15656
  2522
  apply (rule_tac x = y in spec) 
paulson@15656
  2523
  apply (induct_tac x, rule allI) 
paulson@15656
  2524
  apply (case_tac x, simp, simp) 
paulson@15656
  2525
  apply (rule allI, case_tac x, simp, simp) 
paulson@15656
  2526
  by blast
paulson@15656
  2527
paulson@15656
  2528
nipkow@15392
  2529
subsubsection{*Lifting a Relation on List Elements to the Lists*}
nipkow@15302
  2530
nipkow@15302
  2531
consts  listrel :: "('a * 'a)set => ('a list * 'a list)set"
nipkow@15302
  2532
nipkow@15302
  2533
inductive "listrel(r)"
nipkow@15302
  2534
 intros
nipkow@15302
  2535
   Nil:  "([],[]) \<in> listrel r"
nipkow@15302
  2536
   Cons: "[| (x,y) \<in> r; (xs,ys) \<in> listrel r |] ==> (x#xs, y#ys) \<in> listrel r"
nipkow@15302
  2537
nipkow@15302
  2538
inductive_cases listrel_Nil1 [elim!]: "([],xs) \<in> listrel r"
nipkow@15302
  2539
inductive_cases listrel_Nil2 [elim!]: "(xs,[]) \<in> listrel r"
nipkow@15302
  2540
inductive_cases listrel_Cons1 [elim!]: "(y#ys,xs) \<in> listrel r"
nipkow@15302
  2541
inductive_cases listrel_Cons2 [elim!]: "(xs,y#ys) \<in> listrel r"
nipkow@15302
  2542
nipkow@15302
  2543
nipkow@15302
  2544
lemma listrel_mono: "r \<subseteq> s \<Longrightarrow> listrel r \<subseteq> listrel s"
nipkow@15302
  2545
apply clarify  
nipkow@15302
  2546
apply (erule listrel.induct)
nipkow@15302
  2547
apply (blast intro: listrel.intros)+
nipkow@15302
  2548
done
nipkow@15302
  2549
nipkow@15302
  2550
lemma listrel_subset: "r \<subseteq> A \<times> A \<Longrightarrow> listrel r \<subseteq> lists A \<times> lists A"
nipkow@15302
  2551
apply clarify 
nipkow@15302
  2552
apply (erule listrel.induct, auto) 
nipkow@15302
  2553
done
nipkow@15302
  2554
nipkow@15302
  2555
lemma listrel_refl: "refl A r \<Longrightarrow> refl (lists A) (listrel r)" 
nipkow@15302
  2556
apply (simp add: refl_def listrel_subset Ball_def)
nipkow@15302
  2557
apply (rule allI) 
nipkow@15302
  2558
apply (induct_tac x) 
nipkow@15302
  2559
apply (auto intro: listrel.intros)
nipkow@15302
  2560
done
nipkow@15302
  2561
nipkow@15302
  2562
lemma listrel_sym: "sym r \<Longrightarrow> sym (listrel r)" 
nipkow@15302
  2563
apply (auto simp add: sym_def)
nipkow@15302
  2564
apply (erule listrel.induct) 
nipkow@15302
  2565
apply (blast intro: listrel.intros)+
nipkow@15302
  2566
done
nipkow@15302
  2567
nipkow@15302
  2568
lemma listrel_trans: "trans r \<Longrightarrow> trans (listrel r)" 
nipkow@15302
  2569
apply (simp add: trans_def)
nipkow@15302
  2570
apply (intro allI) 
nipkow@15302
  2571
apply (rule impI) 
nipkow@15302
  2572
apply (erule listrel.induct) 
nipkow@15302
  2573
apply (blast intro: listrel.intros)+
nipkow@15302
  2574
done
nipkow@15302
  2575
nipkow@15302
  2576
theorem equiv_listrel: "equiv A r \<Longrightarrow> equiv (lists A) (listrel r)"
nipkow@15302
  2577
by (simp add: equiv_def listrel_refl listrel_sym listrel_trans) 
nipkow@15302
  2578
nipkow@15302
  2579
lemma listrel_Nil [simp]: "listrel r `` {[]} = {[]}"
nipkow@15302
  2580
by (blast intro: listrel.intros)
nipkow@15302
  2581
nipkow@15302
  2582
lemma listrel_Cons:
nipkow@15302
  2583
     "listrel r `` {x#xs} = set_Cons (r``{x}) (listrel r `` {xs})";
nipkow@15302
  2584
by (auto simp add: set_Cons_def intro: listrel.intros) 
nipkow@15302
  2585
nipkow@15302
  2586
nipkow@15392
  2587
subsection{*Miscellany*}
nipkow@15392
  2588
nipkow@15392
  2589
subsubsection {* Characters and strings *}
wenzelm@13366
  2590
wenzelm@13366
  2591
datatype nibble =
wenzelm@13366
  2592
    Nibble0 | Nibble1 | Nibble2 | Nibble3 | Nibble4 | Nibble5 | Nibble6 | Nibble7
wenzelm@13366
  2593
  | Nibble8 | Nibble9 | NibbleA | NibbleB | NibbleC | NibbleD | NibbleE | NibbleF
wenzelm@13366
  2594
wenzelm@13366
  2595
datatype char = Char nibble nibble
wenzelm@13366
  2596
  -- "Note: canonical order of character encoding coincides with standard term ordering"
wenzelm@13366
  2597
wenzelm@13366
  2598
types string = "char list"
wenzelm@13366
  2599
wenzelm@13366
  2600
syntax
wenzelm@13366
  2601
  "_Char" :: "xstr => char"    ("CHR _")
wenzelm@13366
  2602
  "_String" :: "xstr => string"    ("_")
wenzelm@13366
  2603
wenzelm@13366
  2604
parse_ast_translation {*
wenzelm@13366
  2605
  let
wenzelm@13366
  2606
    val constants = Syntax.Appl o map Syntax.Constant;
wenzelm@13366
  2607
wenzelm@13366
  2608
    fun mk_nib n = "Nibble" ^ chr (n + (if n <= 9 then ord "0" else ord "A" - 10));
wenzelm@13366
  2609
    fun mk_char c =
wenzelm@13366
  2610
      if Symbol.is_ascii c andalso Symbol.is_printable c then
wenzelm@13366
  2611
        constants ["Char", mk_nib (ord c div 16), mk_nib (ord c mod 16)]
wenzelm@13366
  2612
      else error ("Printable ASCII character expected: " ^ quote c);
wenzelm@13366
  2613
wenzelm@13366
  2614
    fun mk_string [] = Syntax.Constant "Nil"
wenzelm@13366
  2615
      | mk_string (c :: cs) = Syntax.Appl [Syntax.Constant "Cons", mk_char c, mk_string cs];
wenzelm@13366
  2616
wenzelm@13366
  2617
    fun char_ast_tr [Syntax.Variable xstr] =
wenzelm@13366
  2618
        (case Syntax.explode_xstr xstr of
wenzelm@13366
  2619
          [c] => mk_char c
wenzelm@13366
  2620
        | _ => error ("Single character expected: " ^ xstr))
wenzelm@13366
  2621
      | char_ast_tr asts = raise AST ("char_ast_tr", asts);
wenzelm@13366
  2622
wenzelm@13366
  2623
    fun string_ast_tr [Syntax.Variable xstr] =
wenzelm@13366
  2624
        (case Syntax.explode_xstr xstr of
wenzelm@13366
  2625
          [] => constants [Syntax.constrainC, "Nil", "string"]
wenzelm@13366
  2626
        | cs => mk_string cs)
wenzelm@13366
  2627
      | string_ast_tr asts = raise AST ("string_tr", asts);
wenzelm@13366
  2628
  in [("_Char", char_ast_tr), ("_String", string_ast_tr)] end;
wenzelm@13366
  2629
*}
wenzelm@13366
  2630
berghofe@15064
  2631
ML {*
haftmann@20184
  2632
structure HOList =
haftmann@20184
  2633
struct
haftmann@20184
  2634
haftmann@20184
  2635
local
haftmann@20184
  2636
  val thy = the_context ();
haftmann@20184
  2637
in
haftmann@20184
  2638
  val typ_string = Type (Sign.intern_type thy "string", []);
haftmann@20184
  2639
  fun typ_list ty = Type (Sign.intern_type thy "list", [ty]);
haftmann@20184
  2640
  fun term_list ty f [] = Const (Sign.intern_const thy "Nil", typ_list ty)
haftmann@20184
  2641
    | term_list ty f (x::xs) = Const (Sign.intern_const thy "Cons",
haftmann@20184
  2642
        ty --> typ_list ty --> typ_list ty) $ f x $ term_list ty f xs;
haftmann@20184
  2643
end;
haftmann@20184
  2644
berghofe@15064
  2645
fun int_of_nibble h =
berghofe@15064
  2646
  if "0" <= h andalso h <= "9" then ord h - ord "0"
berghofe@15064
  2647
  else if "A" <= h andalso h <= "F" then ord h - ord "A" + 10
berghofe@15064
  2648
  else raise Match;
berghofe@15064
  2649
berghofe@15064
  2650
fun nibble_of_int i =
berghofe@15064
  2651
  if i <= 9 then chr (ord "0" + i) else chr (ord "A" + i - 10);
haftmann@20181
  2652
haftmann@20184
  2653
fun term_string s =
haftmann@20181
  2654
  let
haftmann@20181
  2655
    val ty_n = Type ("List.nibble", []);
haftmann@20181
  2656
    val ty_c = Type ("List.char", []);
haftmann@20181
  2657
    val ty_l = Type ("List.list", [ty_c]);
haftmann@20181
  2658
    fun mk_nib n = Const ("List.nibble.Nibble" ^ chr (n + (if n <= 9 then ord "0" else ord "A" - 10)), ty_n);
haftmann@20181
  2659
    fun mk_char c =
haftmann@20181
  2660
      if Symbol.is_ascii c andalso Symbol.is_printable c then
haftmann@20181
  2661
        Const ("List.char.Char", ty_n --> ty_n --> ty_c) $ mk_nib (ord c div 16) $ mk_nib (ord c mod 16)
haftmann@20181
  2662
      else error ("Printable ASCII character expected: " ^ quote c);
haftmann@20181
  2663
    fun mk_string c t = Const ("List.list.Cons", ty_c --> ty_l --> ty_l)
haftmann@20181
  2664
      $ mk_char c $ t;
haftmann@20181
  2665
  in fold_rev mk_string (explode s) (Const ("List.list.Nil", ty_l)) end;
haftmann@20184
  2666
haftmann@20184
  2667
end;
berghofe@15064
  2668
*}
berghofe@15064
  2669
wenzelm@13366
  2670
print_ast_translation {*
wenzelm@13366
  2671
  let
wenzelm@13366
  2672
    fun dest_nib (Syntax.Constant c) =
wenzelm@13366
  2673
        (case explode c of
haftmann@20184
  2674
          ["N", "i", "b", "b", "l", "e", h] => HOList.int_of_nibble h
wenzelm@13366
  2675
        | _ => raise Match)
wenzelm@13366
  2676
      | dest_nib _ = raise Match;
wenzelm@13366
  2677
wenzelm@13366
  2678
    fun dest_chr c1 c2 =
wenzelm@13366
  2679
      let val c = chr (dest_nib c1 * 16 + dest_nib c2)
wenzelm@13366
  2680
      in if Symbol.is_printable c then c else raise Match end;
wenzelm@13366
  2681
wenzelm@13366
  2682
    fun dest_char (Syntax.Appl [Syntax.Constant "Char", c1, c2]) = dest_chr c1 c2
wenzelm@13366
  2683
      | dest_char _ = raise Match;
wenzelm@13366
  2684
wenzelm@13366
  2685
    fun xstr cs = Syntax.Appl [Syntax.Constant "_xstr", Syntax.Variable (Syntax.implode_xstr cs)];
wenzelm@13366
  2686
wenzelm@13366
  2687
    fun char_ast_tr' [c1, c2] = Syntax.Appl [Syntax.Constant "_Char", xstr [dest_chr c1 c2]]
wenzelm@13366
  2688
      | char_ast_tr' _ = raise Match;
wenzelm@13366
  2689
wenzelm@13366
  2690
    fun list_ast_tr' [args] = Syntax.Appl [Syntax.Constant "_String",
wenzelm@13366
  2691
            xstr (map dest_char (Syntax.unfold_ast "_args" args))]
wenzelm@13366
  2692
      | list_ast_tr' ts = raise Match;
wenzelm@13366
  2693
  in [("Char", char_ast_tr'), ("@list", list_ast_tr')] end;
wenzelm@13366
  2694
*}
wenzelm@13366
  2695
nipkow@15392
  2696
subsubsection {* Code generator setup *}
berghofe@15064
  2697
berghofe@15064
  2698
ML {*
berghofe@15064
  2699
local
berghofe@15064
  2700
berghofe@16634
  2701
fun list_codegen thy defs gr dep thyname b t =
berghofe@16634
  2702
  let val (gr', ps) = foldl_map (Codegen.invoke_codegen thy defs dep thyname false)
berghofe@15064
  2703
    (gr, HOLogic.dest_list t)
skalberg@15531
  2704
  in SOME (gr', Pretty.list "[" "]" ps) end handle TERM _ => NONE;
berghofe@15064
  2705
haftmann@19607
  2706
fun dest_char (Const ("List.char.Char", _) $ c1 $ c2) =
haftmann@19607
  2707
      let
haftmann@20184
  2708
        fun dest_nibble (Const (s, _)) = (HOList.int_of_nibble o unprefix "List.nibble.Nibble") s
haftmann@19607
  2709
          | dest_nibble _ = raise Match;
haftmann@19607
  2710
      in
haftmann@19607
  2711
        (SOME (dest_nibble c1 * 16 + dest_nibble c2)
haftmann@19607
  2712
        handle Fail _ => NONE | Match => NONE)
haftmann@19607
  2713
      end
haftmann@19607
  2714
  | dest_char _ = NONE;
haftmann@19607
  2715
haftmann@19607
  2716
fun char_codegen thy defs gr dep thyname b t =
haftmann@19607
  2717
  case (Option.map chr o dest_char) t 
haftmann@19607
  2718
   of SOME c =>
haftmann@19607
  2719
        if Symbol.is_printable c
haftmann@19607
  2720
        then SOME (gr, (Pretty.quote o Pretty.str) c)
haftmann@19607
  2721
        else NONE
haftmann@19607
  2722
    | NONE => NONE;
berghofe@15064
  2723
berghofe@15064
  2724
in
berghofe@15064
  2725
wenzelm@18708
  2726
val list_codegen_setup =
haftmann@19607
  2727
  Codegen.add_codegen "list_codegen" list_codegen
haftmann@19607
  2728
  #> Codegen.add_codegen "char_codegen" char_codegen
haftmann@19607
  2729
  #> fold (CodegenPackage.add_pretty_list "Nil" "Cons") [
haftmann@19607
  2730
       ("ml", (7, "::")),
haftmann@19607
  2731
       ("haskell", (5, ":"))
haftmann@19607
  2732
     ]
haftmann@19607
  2733
  #> CodegenPackage.add_appconst
haftmann@20105
  2734
       ("List.char.Char", CodegenPackage.appgen_char dest_char);
berghofe@15064
  2735
berghofe@15064
  2736
end;
berghofe@16770
  2737
*}
berghofe@16770
  2738
berghofe@16770
  2739
types_code
berghofe@16770
  2740
  "list" ("_ list")
berghofe@16770
  2741
attach (term_of) {*
berghofe@15064
  2742
val term_of_list = HOLogic.mk_list;
berghofe@16770
  2743
*}
berghofe@16770
  2744
attach (test) {*
berghofe@15064
  2745
fun gen_list' aG i j = frequency
berghofe@15064
  2746
  [(i, fn () => aG j :: gen_list' aG (i-1) j), (1, fn () => [])] ()
berghofe@15064
  2747
and gen_list aG i = gen_list' aG i i;
berghofe@16770
  2748
*}
berghofe@16770
  2749
  "char" ("string")
berghofe@16770
  2750
attach (term_of) {*
berghofe@15064
  2751
val nibbleT = Type (&quo