bitwise-options.ex

flags = %{
  default: 0,
  sourcepos: 1,
  hardbreaks: 2,
  normalize: 4,
  smart: 8,
  validate_utf8: 16,
  safe: 32
}

options = [
  sourcepos: false,
  safe: false,
  smart: true, # 8
  hardbreaks: true # 2
]

# Finding the correct values works
for {enabled, true} <- options, value = flags[enabled], do: IO.puts "#{enabled}: #{value}"
# [2, 8]

# Gives correct result but seems inelegant
values = for {enabled, true} <- options, value = flags[enabled], do: value

use Bitwise

Enum.reduce(values, fn(x, acc) -> x ||| acc end)