term_evaluator.ex

defmodule TermEvaluator do
  def call(term, pattern: pattern) do
    term = Macro.escape(term)

    ast = quote do
      case unquote(term) do
        unquote(pattern) -> true
        _ -> false
      end
    end

    Code.eval_quoted(ast) |> elem(0)
  end
end

pattern = quote(do: %{signal_strength: strength} when strength < 5)
term = %{signal_strength: 6}

IO.puts TermEvaluator.call(term, pattern: pattern)