> it isn't clear that's what this is Because that's not what this is - this is for when you write e.g. `language plpgsql` in defining some function; instead of

> it isn't clear that's what this is Because that's not what this is - this is for when you write e.g. `language plpgsql` in defining some function; instead of that (with this installed) you could write `language plprolog` and use prolog.