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-module(edit_text).
-export([new/0, new/1, replace/4, add_mark/4, move_mark/3, mark_pos/2,
undo/2, cord/1, walk_backward/3, walk_forward/3]).
-record(text, {cord, marks=[], undo=[], running_undo=[]}).
-record(mark, {name, pos, direction}).
%% ----------------------------------------------------------------------
%% new
new() ->
new(<<>>).
new(BCS) when is_list(BCS) ->
new(cord:new(BCS));
new(Cord) ->
#text{cord=Cord}.
%% ----------------------------------------------------------------------
%% replace (CBS means Cord, Binary, or String)
replace(Text0 = #text{cord=Cord0,marks=Marks0,undo=Undo0}, CBS, Start, Len) ->
Cord1 = cord:replace(Cord0, CBS, Start, Len),
Marks1 = update_marks(Marks0, Start, Start+Len, cbs_length(CBS)),
Undo1 = [{Cord0, Marks0} | Undo0],
%% FIXME: maybe better to chain undo through states (i.e. just
%% know about previous state, which knows about previous state,
%% ...) - if that plays nicely with "running undo"
Text0#text{cord=Cord1, marks=Marks1, undo=Undo1, running_undo=[]}.
cbs_length(L) when is_list(L) -> length(L);
cbs_length(B) when is_binary(B) -> size(B);
cbs_length(C) -> cord:cord_size(C).
update_marks(Marks, Start, End, Len) ->
[update_mark(Mark,Start,End,Len) || Mark <- Marks].
%% Inside the replaced region (includes being on an inserted character)
update_mark(Mark, Start, End, Len)
when Mark#mark.pos >= Start,
Mark#mark.pos < End;
Mark#mark.pos == Start ->
case Mark#mark.direction of
forward ->
Mark#mark{pos=Start+Len};
backward ->
Mark#mark{pos=Start}
end;
%% After the replaced region
update_mark(Mark, Start, End, Len) when Mark#mark.pos >= End ->
%% We move forward by the length-delta
Mark#mark{pos = Mark#mark.pos - (End - Start) + Len};
%% Before the replaced region
update_mark(Mark, _Start, _End, _Len) ->
Mark.
%% ----------------------------------------------------------------------
%% add_mark
add_mark(Text = #text{marks=Marks0}, Name, Pos, Direction) ->
Mark = #mark{name=Name, pos=Pos, direction=Direction},
Text#text{marks=[Mark|Marks0]}.
%% ----------------------------------------------------------------------
%% move_mark
move_mark(Text0, Name, Pos) ->
{Front, [M | Back]} =
lists:splitwith(fun(X) -> X#mark.name /= Name end,
Text0#text.marks),
NewMarks = Front ++ [M#mark{pos=Pos} | Back],
Text0#text{marks=NewMarks}.
%% ----------------------------------------------------------------------
%% mark_pos
mark_pos(#text{marks=Marks}, Name) ->
{found, Mark} = find(fun(M) -> M#mark.name == Name end, Marks),
Mark#mark.pos.
find(_Pred, []) ->
not_found;
find(Pred, [H|T]) ->
case Pred(H) of
true ->
{found, H};
false ->
find(Pred, T)
end.
%% ----------------------------------------------------------------------
%% walk_backward
walk_backward(Text = #text{cord=Cord}, Fun, Pos) ->
Size = cord:cord_size(Cord),
if Pos == Size + 1 ->
case Fun(not_there) of
{more, FNext} ->
walk_backward(Text, FNext, Pos-1);
{result, R} ->
R
end;
true ->
cord:walk(Cord, Pos, backward, Fun)
end.
%% ----------------------------------------------------------------------
%% walk_forward
walk_forward(#text{cord=Cord}, Fun, Pos) ->
cord:walk(Cord, Pos, forward, Fun).
%% ----------------------------------------------------------------------
%% undo
undo(Text0 = #text{undo=Undo, running_undo=Running}, Continuing) ->
Text1 = case Continuing of
true ->
Text0;
false ->
Text0#text{running_undo=Undo}
end,
case Running of
%% Nothing to undo - recycle redo list
[] ->
Text1#text{running_undo=Undo};
[{UndoCord, UndoMarks}|Undos] ->
Text1#text{cord=UndoCord,
marks=UndoMarks,
undo=[{Text0#text.cord, Text0#text.marks} | Undo],
running_undo=Undos}
end.
%% ----------------------------------------------------------------------
%% cord
cord(#text{cord=Cord}) -> Cord.
|
