bind_quoted.ex

defmacro defredis_script(name, script) do
    script_sha = :crypto.hash(:sha, script)
    quote bind_quoted: [script_sha: script_sha, name: name, script: script] do
      def unquote(name)(client, keys \\ [], argv \\ []) do
        query_args = [length(keys)] ++ keys ++ argv
        case Exredis.query client, ["EVALSHA", unquote(script_sha)] ++ query_args do
          <<"NOSCRIPT", _ :: binary>> ->
            Exredis.query client, ["EVAL", unquote(script)] ++ query_args
          reply -> reply
        end
      end
    end
  end
end

module_attr.ex

defmacro defredis_script(name, script) do
    quote do
      @script_sha :crypto.hash(:sha, unquote(script))
      def unquote(name)(client, keys \\ [], argv \\ []) do
        query_args = [length(keys)] ++ keys ++ argv
        case Exredis.query client, ["EVALSHA", @script_sha] ++ query_args do
          <<"NOSCRIPT", _ :: binary>> ->
            Exredis.query client, ["EVAL", unquote(script)] ++ query_args
          reply -> reply
        end
      end
    end
  end
end