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% vim: ft=mercury ts=4 sw=4 et wm=0 tw=0
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% Copyright (C) 1995-1997, 1999-2001, 2004-2006, 2010-2011 The University of Melbourne.
% This file may only be copied under the terms of the GNU Library General
% Public License - see the file COPYING.LIB in the Mercury distribution.
%--------------------------------------------------%
%
% File: assoc_list.m.
% Main authors: fjh, zs.
% Stability: medium to high.
%
% This file contains the definition of the type assoc_list(K, V)
% and some predicates which operate on those types.
%
%--------------------------------------------------%
%--------------------------------------------------%
:- module assoc_list.
:- interface.
:- import_module list.
:- import_module pair.
%--------------------------------------------------%
:- type assoc_list(K, V) == list(pair(K, V)).
:- type assoc_list(T) == list(pair(T, T)).
% Swap the two sides of the pairs in each member of the list.
%
:- func reverse_members(assoc_list(K, V)) = assoc_list(V, K).
:- pred reverse_members(assoc_list(K, V)::in, assoc_list(V, K)::out) is det.
% Zip together two lists.
% Throw an exception if they are of different lengths.
%
:- func from_corresponding_lists(list(K), list(V)) = assoc_list(K, V).
:- pred from_corresponding_lists(list(K)::in, list(V)::in,
assoc_list(K, V)::out) is det.
% Return the first member of each pair.
%
:- func keys(assoc_list(K, V)) = list(K).
:- pred keys(assoc_list(K, V)::in, list(K)::out) is det.
% Return the second member of each pair.
%
:- func values(assoc_list(K, V)) = list(V).
:- pred values(assoc_list(K, V)::in, list(V)::out) is det.
% Return two lists containing respectively the first and the second member
% of each pair in the assoc_list.
%
:- pred keys_and_values(assoc_list(K, V)::in,
list(K)::out, list(V)::out) is det.
% Find the first element of the association list that matches
% the given key, and return the associated value.
%
:- pred search(assoc_list(K, V)::in, K::in, V::out) is semidet.
% An alternative version of search.
%
:- func assoc_list(K, V) ^ elem(K) = V is semidet.
% An alternative version of search that throws an exception if the key in
% question does not appear in the assoc_list.
%
:- func assoc_list(K, V) ^ det_elem(K) = V is det.
% Find the first element of the association list that matches the given
% key. Return the associated value, and the original list with the selected
% element removed.
%
:- pred remove(assoc_list(K, V)::in, K::in, V::out, assoc_list(K, V)::out)
is semidet.
% As above, but with an argument ordering that is more conducive to
% the use of state variable notation.
%
:- pred svremove(K::in, V::out, assoc_list(K, V)::in, assoc_list(K, V)::out)
is semidet.
:- func map_keys_only(func(K) = L, assoc_list(K, V)) = assoc_list(L, V).
:- pred map_keys_only(pred(K, L), assoc_list(K, V), assoc_list(L, V)).
:- mode map_keys_only(pred(in, out) is det, in, out) is det.
:- func map_values_only(func(V) = W, assoc_list(K, V)) = assoc_list(K, W).
:- pred map_values_only(pred(V, W), assoc_list(K, V), assoc_list(K, W)).
:- mode map_values_only(pred(in, out) is det, in, out) is det.
:- func map_values(func(K, V) = W, assoc_list(K, V)) = assoc_list(K, W).
:- pred map_values(pred(K, V, W), assoc_list(K, V), assoc_list(K, W)).
:- mode map_values(pred(in, in, out) is det, in, out) is det.
% filter(Pred, List, TrueList) takes a closure with one
% input argument and for each member K - V of List X, calls the closure
% on the key. K - V is included in TrueList iff Pred(K) is true.
%
:- pred filter(pred(K)::in(pred(in) is semidet),
assoc_list(K, V)::in, assoc_list(K, V)::out) is det.
:- func filter(pred(K)::in(pred(in) is semidet),
assoc_list(K, V)::in) = (assoc_list(K, V)::out) is det.
% negated_filter(Pred, List, FalseList) takes a closure with one
% input argument and for each member K - V of List X, calls the closure
% on the key. K - V is included in FalseList iff Pred(K) is false.
%
:- pred negated_filter(pred(K)::in(pred(in) is semidet),
assoc_list(K, V)::in, assoc_list(K, V)::out) is det.
:- func negated_filter(pred(K)::in(pred(in) is semidet),
assoc_list(K, V)::in) = (assoc_list(K, V)::out) is det.
% filter(Pred, List, TrueList, FalseList) takes a closure with
% one input argument and for each member K - V of List X, calls the closure
% on the key. K - V is included in TrueList iff Pred(K) is true.
% K - V is included in FalseList iff Pred(K) is false.
%
:- pred filter(pred(K)::in(pred(in) is semidet),
assoc_list(K, V)::in, assoc_list(K, V)::out, assoc_list(K, V)::out) is det.
% merge(L1, L2, L):
%
% L is the result of merging the elements of L1 and L2, in ascending order.
% L1 and L2 must be sorted on the keys.
%
:- func merge(assoc_list(K, V), assoc_list(K, V)) = assoc_list(K, V).
:- pred merge(assoc_list(K, V)::in, assoc_list(K, V)::in,
assoc_list(K, V)::out) is det.
% foldl_keys(Pred, List, Start End) calls Pred
% with each key in List (working left-to-right) and an accumulator
% (with initial value of Start), and returns the final value in End.
%
:- pred foldl_keys(pred(K, A, A), assoc_list(K, V), A, A).
:- mode foldl_keys(pred(in, in, out) is det, in, in, out) is det.
:- mode foldl_keys(pred(in, mdi, muo) is det, in, mdi, muo) is det.
:- mode foldl_keys(pred(in, di, uo) is det, in, di, uo) is det.
:- mode foldl_keys(pred(in, in, out) is semidet, in, in, out) is semidet.
:- mode foldl_keys(pred(in, mdi, muo) is semidet, in, mdi, muo) is semidet.
:- mode foldl_keys(pred(in, di, uo) is semidet, in, di, uo) is semidet.
:- mode foldl_keys(pred(in, in, out) is multi, in, in, out) is multi.
:- mode foldl_keys(pred(in, in, out) is nondet, in, in, out) is nondet.
% foldl_values(Pred, List, Start End) calls Pred
% with each value in List (working left-to-right) and an accumulator
% (with initial value of Start), and returns the final value in End.
%
:- pred foldl_values(pred(V, A, A), assoc_list(K, V), A, A).
:- mode foldl_values(pred(in, in, out) is det, in,
in, out) is det.
:- mode foldl_values(pred(in, mdi, muo) is det, in,
mdi, muo) is det.
:- mode foldl_values(pred(in, di, uo) is det, in,
di, uo) is det.
:- mode foldl_values(pred(in, in, out) is semidet, in,
in, out) is semidet.
:- mode foldl_values(pred(in, mdi, muo) is semidet, in,
mdi, muo) is semidet.
:- mode foldl_values(pred(in, di, uo) is semidet, in,
di, uo) is semidet.
:- mode foldl_values(pred(in, in, out) is multi, in,
in, out) is multi.
:- mode foldl_values(pred(in, in, out) is nondet, in,
in, out) is nondet.
% As above, but with two accumulators.
%
:- pred foldl2_values(pred(V, A, A, B, B), assoc_list(K, V),
A, A, B, B).
:- mode foldl2_values(pred(in, in, out, in, out) is det, in,
in, out, in, out) is det.
:- mode foldl2_values(pred(in, in, out, mdi, muo) is det, in,
in, out, mdi, muo) is det.
:- mode foldl2_values(pred(in, in, out, di, uo) is det, in,
in, out, di, uo) is det.
:- mode foldl2_values(pred(in, in, out, in, out) is semidet, in,
in, out, in, out) is semidet.
:- mode foldl2_values(pred(in, in, out, mdi, muo) is semidet, in,
in, out, mdi, muo) is semidet.
:- mode foldl2_values(pred(in, in, out, di, uo) is semidet, in,
in, out, di, uo) is semidet.
:- mode foldl2_values(pred(in, in, out, in, out) is multi, in,
in, out, in, out) is multi.
:- mode foldl2_values(pred(in, in, out, in, out) is nondet, in,
in, out, in, out) is nondet.
% As above, but with three accumulators.
%
:- pred foldl3_values(pred(V, A, A, B, B, C, C), assoc_list(K, V),
A, A, B, B, C, C).
:- mode foldl3_values(pred(in, in, out, in, out, in, out) is det,
in, in, out, in, out, in, out) is det.
:- mode foldl3_values(pred(in, in, out, in, out, mdi, muo) is det,
in, in, out, in, out, mdi, muo) is det.
:- mode foldl3_values(pred(in, in, out, in, out, di, uo) is det,
in, in, out, in, out, di, uo) is det.
:- mode foldl3_values(pred(in, in, out, in, out, in, out) is semidet,
in, in, out, in, out, in, out) is semidet.
:- mode foldl3_values(pred(in, in, out, in, out, mdi, muo) is semidet,
in, in, out, in, out, mdi, muo) is semidet.
:- mode foldl3_values(pred(in, in, out, in, out, di, uo) is semidet,
in, in, out, in, out, di, uo) is semidet.
:- mode foldl3_values(pred(in, in, out, in, out, in, out) is multi,
in, in, out, in, out, in, out) is multi.
:- mode foldl3_values(pred(in, in, out, in, out, in, out) is nondet,
in, in, out, in, out, in, out) is nondet.
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