Bytestring Renderer

[csasarak]

Would there be any interest in accepting a PR which outputs a Doc directly to a Bytestring?

[quchen]

Bytestrings don’t contain text, and this would be an additional dependency. I don’t think this is a good idea. Is there a sprecific use case you need this for?

[csasarak]

It is primarily for this PR I'm working on: tomjaguarpaw/haskell-opaleye#436

We were looking at switching to prettyprinter for rendering SQL queries. The underlying library, postgresql-simple accepts a bytestring. For now, we render to text and then use encodeUtf8 of the text library to turn it into a bytestring. I was going to see if it would be faster to turn a SimpleDocStream into a bytestring directly via the Builder interface instead of going to text and then to bytestring.

[quchen]

I see. Since using Bytestring is a quirk of postgresql-simple (which should really use Text I guess), I think the right place for the renderer would be in Opaleye. It’s not really a lot of code to write your own renderer (see e.g. the ShowS renderer).

I’m not sure you’ll gain much performance in the process though, since Prettyprinter uses Text internally anyway. Writing your own renderer would have to convert the contained Text to Bytestring and then concatenate those, as opposed to simply rendering to one big Text value and then encoding that as a whole like in the straightforward solution.

[csasarak]

Thank you for that insight, I agree it probably doesn't make sense to do it that way anyhow. I'll close this.