README.md

Iteraptor

Handy enumerable operations

• Iteraptor.each/3 to iterate a deeply nested map/list/keyword;
• Iteraptor.map/3 to map a deeply nested map/list/keyword;
• Iteraptor.reduce/4 to reduce a deeply nested map/list/keyword;
• Iteraptor.map_reduce/4 to map and reduce a deeply nested map/list/keyword;
• Iteraptor.filter/3 to filter a deeply nested map/list/keyword;
• Iteraptor.to_flatmap/2 to flatten a deeply nested map/list/keyword into flatten map with concatenated keys;
• Iteraptor.from_flatmap/3 to “unveil”/“unflatten” the previously flattened map into nested structure;
• use Iteraptor.Iteraptable to automagically implement Enumerable and Collectable protocols, as well as Access behaviour on the structure.

bonus:

• Iteraptor.jsonify/2 to prepare the term for JSON interchange; it basically converts keys to strings and keywords to maps because JSON encoders might have issues with serializing keywords.

• Iteraptor.Extras.bury/4 to store the value deeply inside nested term (the intermediate keys are created as necessary.)

HexDocs

• API Reference
• Iteraptor
• Iteraptor.Iteraptable

Usage

Iterating, Mapping, Reducing

# each
iex> %{a: %{b: %{c: 42}}} |> Iteraptor.each(&IO.inspect/1, yield: :all)
# {[:a], %{b: %{c: 42}}}
# {[:a, :b], %{c: 42}}
# {[:a, :b, :c], 42}
%{a: %{b: %{c: 42}}}

# map
iex> %{a: %{b: %{c: 42}}} |> Iteraptor.map(fn {k, _} -> Enum.join(k) end)
%{a: %{b: %{c: "abc"}}}

iex> %{a: %{b: %{c: 42}}}
...> |> Iteraptor.map(fn
...>      {[_], _} = self -> self
...>      {[_, _], _} -> "YAY"
...>    end, yield: :all)
%{a: %{b: "YAY"}}

# reduce
iex> %{a: %{b: %{c: 42}}}
...> |> Iteraptor.reduce([], fn {k, _}, acc ->
...>      [Enum.join(k, "_") | acc]
...>    end, yield: :all)
...> |> :lists.reverse()
["a", "a_b", "a_b_c"]

# map-reduce
iex> %{a: %{b: %{c: 42}}}
...> |> Iteraptor.map_reduce([], fn
...>      {k, %{} = v}, acc -> {{k, v}, [Enum.join(k, ".") | acc]}
...>      {k, v}, acc -> {{k, v * 2}, [Enum.join(k, ".") <> "=" | acc]}
...>    end, yield: :all)
{%{a: %{b: %{c: 42}}}, ["a.b.c=", "a.b", "a"]}

# filter
iex> %{a: %{b: 42, e: %{f: 3.14, c: 42}, d: %{c: 42}}, c: 42, d: 3.14}
...> |> Iteraptor.filter(fn {key, _} -> :c in key end, yield: :none)
%{a: %{e: %{c: 42}, d: %{c: 42}}, c: 42}

Flattening

iex> %{a: %{b: %{c: 42, d: [nil, 42]}, e: [:f, 42]}}
...> |> Iteraptor.to_flatmap(delimiter: "_")
#⇒ %{"a_b_c" => 42, "a_b_d_0" => nil, "a_b_d_1" => 42, "a_e_0" => :f, "a_e_1" => 42}

iex> %{"a.b.c": 42, "a.b.d.0": nil, "a.b.d.1": 42, "a.e.0": :f, "a.e.1": 42}
...> |> Iteraptor.from_flatmap
#⇒ %{a: %{b: %{c: 42, d: [nil, 42]}, e: [:f, 42]}}

Extras

iex> Iteraptor.jsonify([foo: [bar: [baz: :zoo], boo: 42]], values: true)
%{"foo" => %{"bar" => %{"baz" => "zoo"}, "boo" => 42}}

iex> Iteraptor.Extras.bury([foo: :bar], ~w|a b c d|a, 42)
[a: [b: [c: [d: 42]]], foo: :bar]

**As of version 1.2.0 there is an experimental AST traversal feature:

iex> Iteraptor.AST.reduce((quote do: 42), [], fn e, acc -> [e | acc], yield: :all)
'*'

---

Installation

Add iteraptor to your list of dependencies in mix.exs:

def deps, do: [{:iteraptor, "~> 1.5"}]

Changelog

1.13.0

keys: :reverse configuration option in all traversion functions to simplify pattern matching on leaf keys

1.10.0

Iteraptor.jsonify/2 for deep conversion of keyword lists to maps.

1.8.0

Iteraptor.Config for deep substitution of {:system, "VAR"} tuples with the values taken from the system environment in runtime.

1.7.0

Iteraptor.Array with Access support. Basically, Array is the list with Access support.

• 1.7.2 → fixed bug with type recognition for MapSet and Iteraptor.Array.

1.6.0

Iteraptor.jsonify/2.

1.5.0

All iterators do now accept structs: :values keyword argument to prevent nested iteration into structs.

Experimental support for Iteraptable protocol.

1.4.0

Extended support for Iteraptor.Iteraptable:

1.3.0

We now support MapSets.

1.0.0-rc1

Better documentation, Iteraptor.Extras.bury/3.

0.9.0

Complete refactoring, Iteraptor.map/3, Iteraptor.reduce/4, Iteraptor.map_reduce/4.

0.5.0

NB: This functionality is experimental and might not appear in 1.0.0 release.

use Iteraptor.Iteraptable inside structs to make them both Enumerable and Collectable:

defmodule Iteraptor.Struct do
  @fields [field: nil]

  def fields, do: @fields
  defstruct @fields

  use Iteraptor.Iteraptable
end

iex> %Iteraptor.Struct{field: 42}
...>   |> Enum.each(fn e -> IO.inspect(e) end)
#⇒   {:field, 42}

0.4.0

Experimental: support for structs on input. Structs will be automagically created on |> Iteraptor.from_flatmap from keys like StructName%field if a) this structure is known to the system and b) keys are consistent (e. g. there are no subsequent elements, belonging to different structs: ["S1%f" => 42, "S2%f" => 3.14].)

0.3.0

Support for Keyword on input, but it will be output as map for |> Iteraptor.to_flatmap |> Iteraptor.from_flatmap back and forth transformation.