44 lines
1.7 KiB
Plaintext
44 lines
1.7 KiB
Plaintext
(*
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* Copyright 2014, NICTA
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*
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* This software may be distributed and modified according to the terms of
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* the BSD 2-Clause license. Note that NO WARRANTY is provided.
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* See "LICENSE_BSD2.txt" for details.
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*
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* @TAG(NICTA_BSD)
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*)
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chapter "List Manipulation Functions"
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theory List_Lib
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imports "~~/src/HOL/Main"
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begin
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definition list_replace :: "'a list \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'a list" where
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"list_replace list a b \<equiv> map (\<lambda>x. if x = a then b else x) list"
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primrec list_replace_list :: "'a list \<Rightarrow> 'a \<Rightarrow> 'a list \<Rightarrow> 'a list" where
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"list_replace_list [] a list' = []" |
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"list_replace_list (x # xs) a list' = (if x = a then list' @ xs
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else x # list_replace_list xs a list')"
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definition list_swap :: "'a list \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'a list" where
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"list_swap list a b \<equiv> map (\<lambda>x. if x = a then b else if x = b then a else x) list"
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primrec list_insert_after :: "'a list \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'a list" where
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"list_insert_after [] a b = []" |
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"list_insert_after (x # xs) a b = (if x = a then x # b # xs
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else x # list_insert_after xs a b)"
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primrec list_remove :: "'a list \<Rightarrow> 'a \<Rightarrow> 'a list" where
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"list_remove [] a = []" |
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"list_remove (x # xs) a = (if x = a then (list_remove xs a)
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else x # (list_remove xs a))"
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fun after_in_list :: "'a list \<Rightarrow> 'a \<Rightarrow> 'a option" where
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"after_in_list [] a = None" |
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"after_in_list [x] a = None" |
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"after_in_list (x # y # xs) a = (if a = x then Some y else after_in_list (y # xs) a)"
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end
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