Alltid

Alltid offers a simplified approach to editing deeply nested immutable data structures in Elixir.

Inspired by Immer.js in JavaScript, Alltid allows a natural declarative syntax for manipulating deeply nested immutible data structures.

require Alltid

data = %{accounts: [%{id: 1, balance: 200}, %{id: 2, balance: 150}]}

next = Alltid.produce(data, fn draft ->
  draft[:accounts][0][:balance] <- draft[:accounts][0][:balance] + 50
  draft[:accounts][1][:balance] <- draft[:accounts][1][:balance] - 50
end)

This example is simply syntactic sugar for the following:

data = %{accounts: [%{id: 1, balance: 200}, %{id: 2, balance: 150}]}

data
|> put_in([:accounts, Access.at(0), :balance], get_in([:accounts, Access.at(0), :balance]) + 50)
|> put_in([:accounts, Access.at(1), :balance], get_in([:accounts, Access.at(1), :balance]) - 50)

Though Alltid's produce pattern may appear to violate the spirit of functional programming, it simply uses Elixir's macro system and variable bindings to enable a more natural and familiar syntax, entirely isolated to the function passed in to Alltid.produce. The code is still entirely functional.

Installation

If available in Hex, the package can be installed by adding alltid to your list of dependencies in mix.exs:

def deps do
  [
    {:alltid, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/alltid.

jonklein/alltid

Alltid

Installation