zipper

-module(zipper_default).

-export([list/1, bin_tree/1, map_tree/2]).

-spec list(list()) -> zipper:zipper().
list(Root) ->
    IsBranchFun = fun is_list/1,
    ChildrenFun = fun(List) -> List end,
    MakeNodeFun = fun(_Node, Children) -> Children end,
    zipper:new(IsBranchFun, ChildrenFun, MakeNodeFun, Root).

-spec bin_tree({term(), term(), term()}) -> zipper:zipper().
bin_tree(Root) ->
    IsBranchFun = fun(Node) ->
                          is_tuple(Node)
                              andalso (tuple_size(Node) == 3)
                  end,
    ChildrenFun = fun({_, Left, Right}) -> [Left, Right] end,
    MakeNodeFun = fun(Node, [Left, Right]) -> {Node, Left, Right} end,
    zipper:new(IsBranchFun, ChildrenFun, MakeNodeFun, Root).

-spec map_tree(map(), term()) -> zipper:zipper().
map_tree(Root, ChildrenKey) ->
    IsBranchFun = fun (M) ->
                          is_map(M)
                              andalso maps:is_key(ChildrenKey, M)
                              andalso maps:get(ChildrenKey, M) /= []
                      end,
    ChildrenFun = fun(Node) -> maps:get(ChildrenKey, Node) end,
    MakeNodeFun = fun(Node, Children) ->
                          maps:put(ChildrenKey, Children, Node)
                  end,
    zipper:new(IsBranchFun, ChildrenFun, MakeNodeFun, Root).