package travesty
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dune-project
Dependency
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sha256=216c920c872cef2d52fa58e3c49826766a2cf6f2233e64937f18c46c0c5c5388
sha512=3b4f76794666aa3fb16c3639479790df3478a79e6f582b3e66b144e57df26a76580499961dd374f4fb6f3bd2dd7506e2725ed1242bada9deb14eb1916cacd18f
doc/travesty.containers/Travesty_containers/Zipper/Int_mark_zipper/index.html
Module Zipper.Int_mark_zipperSource
Int_mark_zipper is a marked zipper whose marks are integers.
include Zipper_types.S_marked_non_monadic with type mark := Base.int
include Zipper_types.S_non_monadic
The opaque type of zippers.
Construction and destruction
make ~left ~right constructs a zipper with left list left and right list right.
These lists go directly into the zipper itself, so left, if non-empty, should be in the reverse order to how it should appear when fully rewound.
of_list xs converts a list xs to a fully-rewound zipper.
It is equivalent to make with an empty left.
to_list zipper returns the list of _all_ items in the zipper, including those in the left list.
All items appear in the same order that they would take in the right list if the zipper was fully rewound. In other words, the left list appears first (in reverse order), followed by the right list (in forwards order).
To get only the items in the right list, use right_list; to get only the items in the left list (reversed), use left_list.
Querying the left and right lists
left_list zipper gets the raw left list of the zipper: all of the already-processed items in reverse order.
right_list zipper gets the right list of the zipper: all of the not-yet-processed items in forwards order.
to_two_lists zipper is (left_list zipper, right_list zipper).
right_length zipper gets the length of zipper's right list.
Predicates
is_at_start zipper tests whether zipper's left list is empty.
Pushing
push zipper ~value pushes value into zipper at the cursor. The current cursor becomes the second item in the right list, and so on.
push_left zipper ~value pushes value into zipper just to the left of the cursor.
Peeking and popping
peek_opt ?steps zipper retrieves the cursor value without popping it from the zipper. If the cursor is empty, None is returned.
If steps is given, it shifts the effective cursor steps places forwards.
pop zipper returns an error if zipper has no cursor, or Ok (a, zipper') where a is zipper's cursor and zipper' is the new zipper formed by removing a.
pop_opt zipper behaves as pop, but returns None if zipper has no cursor and Some (a, zipper') otherwise.
map_head zipper ~f maps f across the cursor of zipper, if it exists, and replaces the cursor with the result (or drops it if f returns None).
Movement
step ?steps zipper ~on_empty takes one or more steps across zipper. The number of steps defaults to 1 (forwards), but can be given by steps; negative numbers step backwards through the zipper. If the number of steps exceeds the bounds of the zipper, an error is returned.
mark zipper ~mark marks the cursor with mark, and returns the marked-up zipper.
If the cursor is empty, an error is returned.
recall zipper ~mark rewinds zipper until the cursor is on an element previously marked with mark.
If recall runs out of left-list to rewind before finding mark, an error is returned.
val fold_until :
'a t ->
f:
('acc ->
'a ->
'a t ->
(Base.int, 'a, 'acc, 'final) Zipper_types.fold_outcome) ->
init:'acc ->
finish:('acc -> 'a t -> 'final) ->
'finalfold_until zipper ~f ~init ~finish behaves conceptually like List.fold_until, but folds f through the remaining elements of a zipper.
f receives the current accumulator, current cursor, and zipper with cursor popped at each stage. It can't directly modify the zipper mid-fold, but can influence the value of the final zipper provided to the finish continuation by using the various legs of fold_outcome.
delete_to_mark zipper ~mark deletes every item in the left-list up to, and including, the element previously marked with mark.
If delete_to_mark runs out of left-list to rewind before finding mark, an error is returned.