String.char error - (Protocol.UndefinedError) protocol String.Chars not implemented

The error appears to be caused by passing the result of parse to IO.puts; can you show that code?

FWIW, IO.inspect is usually a better tool for printing things mid-calculation, as it can show maps/tuples/PIDs/etc that don’t work with IO.puts.

that is the entire code bit,
however when I call the next function using the IO.inspect I still get the same thing:

  def route(conv) do
    IO.inspect(conv)
  end

the error from the route function:

** (Protocol.UndefinedError) protocol String.Chars not implemented for %{method: "GET", path: "/wildthings", resp_body: ""} of type Map
    (elixir 1.12.3) lib/string/chars.ex:3: String.Chars.impl_for!/1
    (elixir 1.12.3) lib/string/chars.ex:22: String.Chars.to_string/1
    (elixir 1.12.3) lib/io.ex:712: IO.puts/2

and here’s the thing, this is the 3rd or fourth time I’m going thru this chapter for reviewing and practicing and did not have the problem before, but I was using a windows box, now I’m using a mac with the latest elixir version if that makes any difference.
when I comment the IO.inspect on the route function, the error goes away… bummer

PS: thanks for your response

in looking at the protocol implementation code:

defmodule Protocol.UndefinedError do
  defexception [:protocol, :value, description: ""]

  @impl true
  def message(%{protocol: protocol, value: value, description: description}) do
    "protocol #{inspect(protocol)} not implemented for #{inspect(value)} of type " <>
      value_type(value) <> maybe_description(description) <> maybe_available(protocol)
  end

  defp value_type(%{__struct__: struct}), do: "#{inspect(struct)} (a struct)"
  defp value_type(value) when is_atom(value), do: "Atom"
  defp value_type(value) when is_bitstring(value), do: "BitString"
  defp value_type(value) when is_float(value), do: "Float"
  defp value_type(value) when is_function(value), do: "Function"
  defp value_type(value) when is_integer(value), do: "Integer"
  defp value_type(value) when is_list(value), do: "List"
  defp value_type(value) when is_map(value), do: "Map"
  defp value_type(value) when is_pid(value), do: "PID"
  defp value_type(value) when is_port(value), do: "Port"
  defp value_type(value) when is_reference(value), do: "Reference"
  defp value_type(value) when is_tuple(value), do: "Tuple"

  defp maybe_description(""), do: ""
  defp maybe_description(description), do: ", " <> description

  defp maybe_available(protocol) do
    case protocol.__protocol__(:impls) do
      {:consolidated, []} ->
        ". There are no implementations for this protocol."

      {:consolidated, types} ->
        ". This protocol is implemented for the following type(s): " <>
          Enum.map_join(types, ", ", &inspect/1)

      :not_consolidated ->
        ""
    end
  end
end

the protocol definition code.

That is by design, you shouldn’t be trying to print a map. The bug is that somewhere in your code you are trying to treat a map as a map. You have a parse function, what do you do with its result, how is it called?

IO.inspect returns its argument so your route function passes the map along to… whatever code is actually calling IO.puts (still not shown ) and you get the same error.

Commenting out the whole IO.inspect line will make route return nil, which IO.puts is fine with (it prints a single newline).

thanks for all of your comments, the issue were some hidden chars on the file, I created a new file and re-typed the code and the problem went away… need a new keyboard LoL, got to blame it on something…
anywho: alls ok now…