if_else_approach.ex

  def add_attr(event_attr, person_attrs) do
    new_attr_value = [%Person.AttributeValue{
      :timestamp => event_attr.timestamp,
      :confidence => event_attr.confidence,
      :value => event_attr.value
    }]
    curr_attr = Map.get(person_attrs, event_attr.field)
    if (curr_attr === nil) do #the person doesn't have that attr
      # add_new(person_attrs, )
      new_attr_source = %{
        event_attr.source => new_attr_value
      }
      Map.update(person_attrs, event_attr.field, new_attr_source, fn(_) -> new_attr_source end)
    else #the person has that attr
      curr_source = Map.get(curr_attr, event_attr.source)
      if (curr_source === nil) do #but they dont have that source
        new_field_map = Map.update(curr_attr, event_attr.source, new_attr_value, fn(_) -> new_attr_value end)
        Map.update(person_attrs, event_attr.field, new_field_map, fn(_) -> new_field_map end)
      else #they have the attr and source
        [elem|_] = curr_source
        if (event_attr.timestamp > elem.timestamp) do #and this one is newer
          new_field_map = Map.update(curr_attr, event_attr.source, new_attr_value, fn(_) -> new_attr_value end)
          Map.update(person_attrs, event_attr.field, new_field_map, fn(_) -> new_field_map end)
        else #it's older. ignore it.
          person_attrs
        end
      end
    end
  end

person_event.ex

defmodule Person.EventAttributeValue do
  @type t :: %{
    :field => String.t,
    :source => String.t,
    :timestamp => integer(),
    :confidence => number(),
    :value => any()
  }
  defstruct field: nil, source: nil, timestamp: 0, confidence: 0, value: nil
end

defmodule Person.AttributeValue do
  @type t :: %{
    :timestamp => integer(),
    :confidence => number(),
    :value => any()
  }
  defstruct timestamp: 0, confidence: 0, value: nil
end





defmodule KBS.Person do
  @spec add_attr(Person.EventAttributeValue.t, map()) :: map()
  def add_attr(
    %Person.EventAttributeValue{
      :field => event_field,
      :source => event_source,
      :timestamp => event_timestamp,
      :confidence => event_confidence,
      :value => event_value
    } = event_attr,
    %{
      "field_name" => field_name =
        %{ "source_name" => source_name = [
          %Person.AttributeValue{
            :timestamp => attr_timestamp,
            :confidence => attr_confidence,
            :value => attr_value
          }
        ]
      }
    } = person_attrs) do

    IO.puts "event_field: #{event_field}"
    IO.puts "event_field: #{event_field}"
    IO.puts "event_source: #{event_source}"
    IO.puts "event_timestamp: #{event_timestamp}"
    IO.puts "event_confidence: #{event_confidence}"
    IO.puts "event_value: #{event_value}"
    # IO.puts "field_name: #{inspect field_name}"
    # IO.puts "source_name: #{source_name}"
    # IO.puts "attr_timestamp: #{attr_timestamp}"
    # IO.puts "attr_confidence: #{attr_confidence}"
    # IO.puts "attr_value: #{attr_value}"
  end
end