Zippy

Zippy is an Elixir implementation of Fred Hebert's Zippers erlang library. The main motivation was of course to better grasp this kind of data structures, but I also added my own grain of salt in some parts:

• When returning an {:ok, value} tuple in case of success, functions will also return a {:error, nil} in case of failure.
• All :undefined atoms have been replaced by nil, which I find more idiomatic.
• Idiomatic function names (if_leaf ➜ leaf?) when needed.
• Functions' first argument is the data structure, which allows chaining operations on it with the |> operator.

This package follows semantic versioning:

Major.Minor.Patch
  └────┼─────┼──> Incompatible API changes
       └─────┼────> More features
             └──────> Bug Fixing

Examples

Let's say we can modelize the wanderings of a user in their filesystem's hierarchy with a {timestamp, path} tuple. The code would look like that:

alias Zippy.ZList, as: Z
zlist = Z.new
timestamp = fn -> DateTime.utc_now \|> DateTime.to_unix end

hist0 = zlist \|> Z.insert({timestamp.(), "/home"})
hist1 = hist0 \|> Z.next \|> Z.insert({timestamp.(), "/home/foo"})
hist2 = hist1 \|> Z.next \|> Z.insert({timestamp.(), "/home/foo/.local"})
hist3 = hist2 \|> Z.next \|> Z.insert({timestamp.(), "/home/foo/.local/bin"})

If we wanted to browse the events list, we would use the next/2 and prev/2 functions from Zippy.ZList.

Installation

def deps do
  [{:zippy, "~> 0.0.1"}]
end

License

MIT License

Copyright © 2017 Théophile Choutri

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.