Re: RFC: style cleanup & guidelines for GHC, and related bikeshedding

Johan Tibell :

On Thu, Jul 17, 2014 at 8:40 AM, Simon Peyton Jones wrote:

...

| I used to be a 80 column guy, but moved away from that the last years. | But you are right, there must be an upper limit and, if >80 is a | problem for code reviews, then it's a reasonable choice.

As laptop screens have successively more horizontal pixels and fewer vertical pixels, longer lines use screen real estate better. 80 columns now seems a bit narrow to me. 100 would be better.

But I'm not going to die for this

Here we go!

* Wider screens let you have several Emacs buffers next to each other. At 80 chars you can have about 2 buffers next to each other on a 13" screen.

I think that was SimonM's premise for code reviews, that you want lines short enough to have two versions besides each other.

* The average line length is about 30-35 characters in Python. If it's anything similar in Haskell shorter line length are more efficient, looking how much of the lines times columns space is filled with characters.

The problem is that indentation and long identifiers push you towards longer lines.

* The eye has trouble traveling back to the next line if lines get too long (at least when reading prose). Research says around 60-70 characters is optimal, if I recall correctly.

I think we read code differently to prose (and prose is not much indented), so I don't think these numbers transfer. Manuel