src/HOL/Library/AList.thy
changeset 46237 99c80c2f841a
parent 46236 ae79f2978a67
child 46238 9ace9e5b79be
equal deleted inserted replaced
46236:ae79f2978a67 46237:99c80c2f841a
     1 (*  Title:      HOL/Library/AList.thy
       
     2     Author:     Lukas Bulwahn, TU Muenchen *)
       
     3 
       
     4 header {* Abstract type of association lists with unique keys *}
       
     5 
       
     6 theory AList
       
     7 imports AList_Impl
       
     8 begin
       
     9 
       
    10 text {* This was based on some existing fragments in the AFP-Collection framework. *}
       
    11 
       
    12 subsection {* Type @{text "('key, 'value) alist" } *}
       
    13 
       
    14 typedef (open) ('key, 'value) alist = "{xs :: ('key \<times> 'value) list. distinct (map fst xs)}"
       
    15 morphisms impl_of Alist
       
    16 by(rule exI[where x="[]"]) simp
       
    17 
       
    18 lemma alist_ext: "impl_of xs = impl_of ys \<Longrightarrow> xs = ys"
       
    19 by(simp add: impl_of_inject)
       
    20 
       
    21 lemma alist_eq_iff: "xs = ys \<longleftrightarrow> impl_of xs = impl_of ys"
       
    22 by(simp add: impl_of_inject)
       
    23 
       
    24 lemma impl_of_distinct [simp, intro]: "distinct (map fst (impl_of xs))"
       
    25 using impl_of[of xs] by simp
       
    26 
       
    27 lemma Alist_impl_of [code abstype]: "Alist (impl_of xs) = xs"
       
    28 by(rule impl_of_inverse)
       
    29 
       
    30 subsection {* Primitive operations *}
       
    31 
       
    32 definition lookup :: "('key, 'value) alist \<Rightarrow> 'key \<Rightarrow> 'value option"
       
    33 where [code]: "lookup xs = map_of (impl_of xs)" 
       
    34 
       
    35 definition empty :: "('key, 'value) alist"
       
    36 where [code del]: "empty = Alist []"
       
    37 
       
    38 definition update :: "'key \<Rightarrow> 'value \<Rightarrow> ('key, 'value) alist \<Rightarrow> ('key, 'value) alist"
       
    39 where [code del]: "update k v xs = Alist (AList_Impl.update k v (impl_of xs))"
       
    40 
       
    41 (* FIXME: we use an unoptimised delete operation. *)
       
    42 definition delete :: "'key \<Rightarrow> ('key, 'value) alist \<Rightarrow> ('key, 'value) alist"
       
    43 where [code del]: "delete k xs = Alist (AList_Impl.delete k (impl_of xs))"
       
    44 
       
    45 definition map_entry :: "'key \<Rightarrow> ('value \<Rightarrow> 'value) \<Rightarrow> ('key, 'value) alist \<Rightarrow> ('key, 'value) alist"
       
    46 where [code del]: "map_entry k f xs = Alist (AList_Impl.map_entry k f (impl_of xs))" 
       
    47 
       
    48 definition filter :: "('key \<times> 'value \<Rightarrow> bool) \<Rightarrow> ('key, 'value) alist \<Rightarrow> ('key, 'value) alist"
       
    49 where [code del]: "filter P xs = Alist (List.filter P (impl_of xs))"
       
    50 
       
    51 definition map_default :: "'key => 'value => ('value => 'value) => ('key, 'value) alist => ('key, 'value) alist"
       
    52 where
       
    53   "map_default k v f xs = Alist (AList_Impl.map_default k v f (impl_of xs))"
       
    54 
       
    55 lemma impl_of_empty [code abstract]: "impl_of empty = []"
       
    56 by (simp add: empty_def Alist_inverse)
       
    57 
       
    58 lemma impl_of_update [code abstract]: "impl_of (update k v xs) = AList_Impl.update k v (impl_of xs)"
       
    59 by (simp add: update_def Alist_inverse distinct_update)
       
    60 
       
    61 lemma impl_of_delete [code abstract]:
       
    62   "impl_of (delete k al) = AList_Impl.delete k (impl_of al)"
       
    63 unfolding delete_def by (simp add: Alist_inverse distinct_delete)
       
    64 
       
    65 lemma impl_of_map_entry [code abstract]:
       
    66   "impl_of (map_entry k f xs) = AList_Impl.map_entry k f (impl_of xs)"
       
    67 unfolding map_entry_def by (simp add: Alist_inverse distinct_map_entry)
       
    68 
       
    69 lemma distinct_map_fst_filter:
       
    70    "distinct (map fst xs) ==> distinct (map fst (List.filter P xs))"
       
    71 by (induct xs) auto
       
    72 
       
    73 lemma impl_of_filter [code abstract]:
       
    74   "impl_of (filter P xs) = List.filter P (impl_of xs)"
       
    75 unfolding filter_def by (simp add: Alist_inverse distinct_map_fst_filter)
       
    76 
       
    77 lemma impl_of_map_default [code abstract]:
       
    78   "impl_of (map_default k v f xs) = AList_Impl.map_default k v f (impl_of xs)"
       
    79 by (auto simp add: map_default_def Alist_inverse distinct_map_default)
       
    80 
       
    81 subsection {* Abstract operation properties *}
       
    82 
       
    83 (* FIXME: to be completed *)
       
    84 
       
    85 lemma lookup_empty [simp]: "lookup empty k = None"
       
    86 by(simp add: empty_def lookup_def Alist_inverse)
       
    87 
       
    88 lemma lookup_delete [simp]: "lookup (delete k al) = (lookup al)(k := None)"
       
    89 by (simp add: lookup_def delete_def Alist_inverse distinct_delete delete_conv')
       
    90 
       
    91 subsection {* Further operations *}
       
    92 
       
    93 subsubsection {* Equality *}
       
    94 
       
    95 instantiation alist :: (equal, equal) equal begin
       
    96 
       
    97 definition "HOL.equal (xs :: ('a, 'b) alist) ys == impl_of xs = impl_of ys"
       
    98 
       
    99 instance
       
   100 proof
       
   101 qed (simp add: equal_alist_def impl_of_inject)
       
   102 
       
   103 end
       
   104 
       
   105 subsubsection {* Size *}
       
   106 
       
   107 instantiation alist :: (type, type) size begin
       
   108 
       
   109 definition "size (al :: ('a, 'b) alist) = length (impl_of al)"
       
   110 
       
   111 instance ..
       
   112 
       
   113 end
       
   114 
       
   115 subsection {* Quickcheck generators *}
       
   116 
       
   117 notation fcomp (infixl "\<circ>>" 60)
       
   118 notation scomp (infixl "\<circ>\<rightarrow>" 60)
       
   119 
       
   120 definition (in term_syntax)
       
   121   valterm_empty :: "('key :: typerep, 'value :: typerep) alist \<times> (unit \<Rightarrow> Code_Evaluation.term)"
       
   122 where
       
   123   "valterm_empty = Code_Evaluation.valtermify empty"
       
   124 
       
   125 definition (in term_syntax)
       
   126   valterm_update :: "'key :: typerep \<times> (unit \<Rightarrow> Code_Evaluation.term) \<Rightarrow>
       
   127   'value :: typerep \<times> (unit \<Rightarrow> Code_Evaluation.term) \<Rightarrow>
       
   128   ('key, 'value) alist \<times> (unit \<Rightarrow> Code_Evaluation.term) \<Rightarrow>
       
   129   ('key, 'value) alist \<times> (unit \<Rightarrow> Code_Evaluation.term)" where
       
   130   [code_unfold]: "valterm_update k v a = Code_Evaluation.valtermify update {\<cdot>} k {\<cdot>} v {\<cdot>}a"
       
   131 
       
   132 fun (in term_syntax) random_aux_alist 
       
   133 where
       
   134   "random_aux_alist i j = (if i = 0 then Pair valterm_empty else Quickcheck.collapse (Random.select_weight [(i, Quickcheck.random j \<circ>\<rightarrow> (%k. Quickcheck.random j \<circ>\<rightarrow> (%v. random_aux_alist (i - 1) j \<circ>\<rightarrow> (%a. Pair (valterm_update k v a))))), (1, Pair valterm_empty)]))"
       
   135 
       
   136 instantiation alist :: (random, random) random
       
   137 begin
       
   138 
       
   139 definition random_alist
       
   140 where
       
   141   "random_alist i = random_aux_alist i i"
       
   142  
       
   143 instance ..
       
   144 
       
   145 end
       
   146 
       
   147 no_notation fcomp (infixl "\<circ>>" 60)
       
   148 no_notation scomp (infixl "\<circ>\<rightarrow>" 60)
       
   149 
       
   150 instantiation alist :: (exhaustive, exhaustive) exhaustive
       
   151 begin
       
   152 
       
   153 fun exhaustive_alist :: "(('a, 'b) alist => (bool * term list) option) => code_numeral => (bool * term list) option"
       
   154 where
       
   155   "exhaustive_alist f i = (if i = 0 then None else case f empty of Some ts => Some ts | None =>
       
   156      exhaustive_alist (%a. Quickcheck_Exhaustive.exhaustive (%k. Quickcheck_Exhaustive.exhaustive (%v. f (update k v a)) (i - 1)) (i - 1)) (i - 1))"
       
   157 
       
   158 instance ..
       
   159 
       
   160 end
       
   161 
       
   162 instantiation alist :: (full_exhaustive, full_exhaustive) full_exhaustive
       
   163 begin
       
   164 
       
   165 fun full_exhaustive_alist :: "(('a, 'b) alist * (unit => term) => (bool * term list) option) => code_numeral => (bool * term list) option"
       
   166 where
       
   167   "full_exhaustive_alist f i = (if i = 0 then None else case f valterm_empty of Some ts => Some ts | None =>
       
   168      full_exhaustive_alist (%a. Quickcheck_Exhaustive.full_exhaustive (%k. Quickcheck_Exhaustive.full_exhaustive (%v. f (valterm_update k v a)) (i - 1)) (i - 1)) (i - 1))"
       
   169 
       
   170 instance ..
       
   171 
       
   172 end
       
   173 
       
   174 hide_const valterm_empty valterm_update random_aux_alist
       
   175 
       
   176 hide_fact (open) lookup_def empty_def update_def delete_def map_entry_def filter_def map_default_def
       
   177 hide_const (open) impl_of lookup empty update delete map_entry filter map_default 
       
   178 
       
   179 end