Add a from optional function

[CrowdHailer]

{:ok, value} = OK.optional(value)
{:error, :none} = OK.optional(nil)

perhaps provide reason

{:error, reason} = OK.optional(nil, reason: :needs_value)

port = OK.optional(Map.get(config, "port"), reason)

[CrowdHailer]

When this is added we should handle the case of a single line inside the block.

OK.try do
  perform(action)
else
  %ArgumentError{} ->
    {:error, %BadRequest{}}
end

[CrowdHailer]

call required not optional

[ghost]

So perhaps your port example could look like this?

port = 
  config
  |> Map.get("port")
  |> OK.required(reason: :needs_value)

[CrowdHailer]

I like that.

[CrowdHailer]

Added in PR #26, check it out.