mercurylang/mercury
1
0
Fork 0
mirror of https://github.com/Mercury-Language/mercury.git synced 2025-12-18 15:26:31 +00:00
Code Issues Projects Releases Wiki Activity

Added to_list, put_on_front, put_list_on_front, and get_from_back.

Browse Source 
Estimated hours taken: 0.75
Branches: main

library/queue.m:
library/svqueue.m:
	Added to_list, put_on_front, put_list_on_front, and get_from_back.
	Added svqueue.put_on_front, svqueue.put_list_on_front, and
	svqueue.get_from_back.
	Cosmetic changes to comments in svqueue.m.

NEWS:
	Mention the new additions.
This commit is contained in:
Ralph Becket
2005-01-27 03:17:49 +00:00
parent 4f2a8bf27d
commit 30817e5b98
3 changed files with 97 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
NEWS
View File

@@ -130,7 +130,12 @@ Changes to the Mercury language:
Changes to the Mercury standard library:
* We've add the function queue.from_list/1 as a synonym for
queue.list_to_queue/1.
queue.list_to_queue/1, function queue.to_list/1 (and predicate
queue.to_list/2) as the converse of queue.from_list/1, queue.put_on_front/2
(and predicate queue.put_on_front/3) to put items on to the front of a
queue, queue.put_list_on_front/2 (and predicate queue.put_list_on_front/3)
to put a list of items on to the front of a queue, and predicate
queue.get_from_back/3 which removes the last element from a queue.
* We've added the function pqueue.from_assoc_list/1 as a synonym
for pqueue.assoc_list_to_pqueue/1.

64
library/queue.m
View File

@@ -88,6 +88,10 @@
%
:- func queue__from_list(list(T)) = queue(T).
% `queue__to_list(Queue) = List' is the inverse of queue__from_list/1.
%
:- func queue__to_list(queue(T)) = list(T).
% `queue__delete_all(Queue0, Elem, Queue)' is true iff `Queue' is
% the same queue as `Queue0' with all occurrences of `Elem' removed
% from it.
@@ -95,6 +99,25 @@
:- pred queue__delete_all(queue(T)::in, T::in, queue(T)::out) is det.
:- func queue__delete_all(queue(T), T) = queue(T).
% `queue__put_on_front(Queue0, Elem) = Queue' pushes `Elem' on to
% the front of `Queue0', giving `Queue'.
%
:- func queue__put_on_front(queue(T), T) = queue(T).
:- pred queue__put_on_front(queue(T)::in, T::in, queue(T)::out) is det.
% `queue__put_list_on_front(Queue0, Elems) = Queue' pushes `Elems'
% on to the front of `Queue0', giving `Queue' (the Nth member
% of `Elems' becomes the Nth member from the front of `Queue').
%
:- func queue__put_list_on_front(queue(T), list(T)) = queue(T).
:- pred queue__put_list_on_front(queue(T)::in, list(T)::in, queue(T)::out)
is det.
% `queue__get_from_back(Queue0, Elem, Queue)' removes `Elem' from
% the back of `Queue0', giving `Queue'.
%
:- pred queue__get_from_back(queue(T)::in, T::out, queue(T)::out) is semidet.
%--------------------------------------------------------------------------%
%--------------------------------------------------------------------------%
@@ -166,6 +189,8 @@ queue__list_to_queue(List, [] - List).
queue__from_list(List) = [] - List.
queue__to_list(On - Off) = Off ++ list__reverse(On).
queue__delete_all(On0 - Off0, Elem, On - Off) :-
list__delete_all(On0, Elem, On1),
list__delete_all(Off0, Elem, Off1),
@@ -177,6 +202,45 @@ queue__delete_all(On0 - Off0, Elem, On - Off) :-
Off = Off1
).
queue__put_on_front(On - Off, Elem, On - [Elem | Off]).
queue__put_on_front(Queue0, Elem) = Queue :-
queue__put_on_front(Queue0, Elem, Queue).
queue__put_list_on_front(On - Off, Elems, On - (Elems ++ Off)).
queue__put_list_on_front(Queue0, Elems) = Queue :-
queue__put_list_on_front(Queue0, Elems, Queue).
queue__get_from_back(On0 - Off0, Elem, On - Off) :-
(
% The On list is non-empty and the last element
% in the queue is the head of the On list.
%
On0 = [Elem | On],
Off = Off0
;
% The On list is empty.
%
On0 = [],
(
% The Off list contains a single element.
%
Off0 = [Elem],
On = [],
Off = []
;
% The Off list contains two or more elements.
% We split it in two and take the head of the
% new On list as Elem.
%
Off0 = [_, _ | _],
N = list__length(Off0),
list__split_list(N / 2, Off0, Off, RevOn),
[Elem | On] = list__reverse(RevOn)
)
).
%--------------------------------------------------------------------------%
%--------------------------------------------------------------------------%
% Ralph Becket <rwab1@cl.cam.ac.uk> 29/04/99

27
library/svqueue.m
View File

@@ -46,6 +46,23 @@
%
:- pred svqueue__delete_all(T::in, queue(T)::in, queue(T)::out) is det.
% `svqueue__put_on_front(Elem, Queue0, Queue)' pushes `Elem' on to
% the front of `Queue0', giving `Queue'.
%
:- pred svqueue__put_on_front(T::in, queue(T)::in, queue(T)::out) is det.
% `svqueue__put_list_on_front(Queue0, Elems, Queue)' pushes `Elems'
% on to the front of `Queue0', giving `Queue' (the Nth member
% of `Elems' becomes the Nth member from the front of `Queue').
%
:- pred svqueue__put_list_on_front(list(T)::in, queue(T)::in, queue(T)::out)
is det.
% `queue__get_from_back(Elem, Queue0, Queue)' removes `Elem' from
% the back of `Queue0', giving `Queue'.
%
:- pred svqueue__get_from_back(T::out, queue(T)::in, queue(T)::out) is semidet.
%--------------------------------------------------------------------------%
%--------------------------------------------------------------------------%
@@ -62,3 +79,13 @@ svqueue__get(Elem, Queue0, Queue) :-
svqueue__delete_all(Elem, Queue0, Queue) :-
queue__delete_all(Queue0, Elem, Queue).
svqueue__put_on_front(Elem, Queue0, Queue) :-
queue__put_on_front(Queue0, Elem, Queue).
svqueue__put_list_on_front(Elems, Queue0, Queue) :-
queue__put_list_on_front(Queue0, Elems, Queue).
svqueue__get_from_back(Elem, Queue0, Queue) :-
queue__get_from_back(Queue0, Elem, Queue).