lh-l4v/lib/DataMap.thy

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(*
* Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
*
* SPDX-License-Identifier: BSD-2-Clause
*)
theory DataMap
imports Main
begin
type_synonym ('k, 'a) map = "'k \<rightharpoonup> 'a"
definition
data_map_empty :: "('k, 'a) map"
where
data_map_empty_def[simp]: "data_map_empty \<equiv> Map.empty"
definition
data_map_insert :: "'k \<Rightarrow> 'a \<Rightarrow> ('k, 'a) map \<Rightarrow> ('k, 'a) map"
where
data_map_insert_def[simp]: "data_map_insert x y m \<equiv> (m (x \<mapsto> y))"
definition
lookupBefore :: "('k :: {linorder, finite}) \<Rightarrow> ('k, 'a) map \<Rightarrow> ('k \<times> 'a) option"
where
"lookupBefore x m \<equiv>
let Ks = {k \<in> dom m. k \<le> x}
in if Ks = {} then None
else Some (Max Ks, the (m (Max Ks)))"
definition
lookupAround :: "('k :: {linorder, finite}) \<Rightarrow> ('k, 'a) map
\<Rightarrow> (('k \<times> 'a) option \<times> 'a option \<times> ('k \<times> 'a) option)"
where
"lookupAround x m \<equiv>
let Bs = {k \<in> dom m. k < x};
As = {k \<in> dom m. k > x}
in (if Bs = {} then None else Some (Max Bs, the (m (Max Bs))),
m x,
if As = {} then None else Some (Min As, the (m (Min Bs))))"
definition
data_map_filterWithKey :: "('k \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> ('k, 'a) map \<Rightarrow> ('k, 'a) map"
where
"data_map_filterWithKey f m \<equiv> \<lambda>x. case m x of
None \<Rightarrow> None
| Some y \<Rightarrow> if f x y then Some y else None"
abbreviation(input)
"data_set_empty \<equiv> {}"
abbreviation(input)
"data_set_insert \<equiv> insert"
abbreviation(input)
"data_set_delete x S \<equiv> S - {x}"
end