Sorry for my misunderstanding regarding comments. I got frustrated by some recent Scala bashing posts that had comments disabled, and mistakenly assumed there was a pattern. I meant to respond directly to your blog, but now that the discussion on HN is in full swing, we should keep it here.
As someone who struggled myself for a long time with the design of collections until the pieces fell into place, I can understand your struggles very well. In every language there is a limit of what can be achieved, and there is a grey zone before that where things get messy. I believe that Scala collections pushed the envelope in terms of flexibility and ease of use. But repeating this feat by extending all kinds of collections and collection-like structures generically with your own operations is not at all trivial.
You are absolutely right to point out when things get messy of course, even if it would be only to serve as a warning to others who might follow you.
The question is how to avoid similar experiences in the future. One can either change the language to make simple what you found hard. But before I buy into that, I would like to see a constructive and complete proposal what one should change.
Or, one could make a better effort to delineate the limits and the grey zone. That's what I proposed. Importantly, my proposal would only apply to definitions not to usages. So I'd put implicit conversions and definitions with higher-kinded types behind a flag, but not their uses. I hope this would give pause to library designers that mix advanced features with too much abandon, but it would not hinder users of these libraries at all.
As someone who struggled myself for a long time with the design of collections until the pieces fell into place, I can understand your struggles very well. In every language there is a limit of what can be achieved, and there is a grey zone before that where things get messy. I believe that Scala collections pushed the envelope in terms of flexibility and ease of use. But repeating this feat by extending all kinds of collections and collection-like structures generically with your own operations is not at all trivial.
You are absolutely right to point out when things get messy of course, even if it would be only to serve as a warning to others who might follow you.
The question is how to avoid similar experiences in the future. One can either change the language to make simple what you found hard. But before I buy into that, I would like to see a constructive and complete proposal what one should change.
Or, one could make a better effort to delineate the limits and the grey zone. That's what I proposed. Importantly, my proposal would only apply to definitions not to usages. So I'd put implicit conversions and definitions with higher-kinded types behind a flag, but not their uses. I hope this would give pause to library designers that mix advanced features with too much abandon, but it would not hinder users of these libraries at all.