Differ

Small library for creating diffs and applying them

iex> Differ.diff("Hello!", "Hey!")
[eq: "He", del: "llo", ins: "y", eq: "!"]

iex> Differ.patch("Hello!", [eq: "He", del: "llo", ins: "y", eq: "!"])
{:ok, "Hey!"}

Installation

The package can be installed by adding differ to your list of dependencies in mix.exs:

def deps do
  [
    {:differ, "~> 0.1.1"}
  ]
end

Documentation

Documentation can be found at https://hexdocs.pm/differ.

Usage

Simple diff of two maps

iex> user = %{name: "John"}
iex> updated_user = Map.put(user, :age, 25)
iex> Differ.diff(user, updated_user)
[{:name, :eq, "John"}, {:age, :ins, 25}]

For lists and strings using List.myers_difference/3 and String.myers_difference/2 respectevly. So diffs of lists and strings a excactly output of this functions

iex> Differ.diff("Hello!", "Hey!")
[eq: "He", del: "llo", ins: "y", eq: "!"]

It is possible to use Differ with structs, you need to derive default implementation for Differ.Diffable and Differ.Patchable protocols:

defmodule User do
    @derive [Differ.Diffable, Differ.Patchable]
    defstruct name: "", age: 21
end

And now you can call Differ.diff/2 with your structs:

iex> Differ.diff(%User{name: "John"}, %User{name: "John Smith"})
[{:name, :diff, [eq: "John", ins: " Smith"]}, {:age, :eq, 21}]

As well as creating diffs, you can apply diff to a term. There is Differ.patch/2 and Differ.revert/2 for this purposes.

iex> diff = Differ.diff("Hello!", "Hey!")
iex> Differ.patch("Hello!", diff)
{:ok, "Hey!"}

or revert diff

iex> Differ.revert("Hey!", diff)
{:ok, "Hello!"}

For more examples look at the docs.