Re: Line length for code?

[John W. Eaton]

On 01/23/2016 05:19 PM, Rik wrote:

> In changeset 21133:31674b9d202b, "NEWS: Refill text to 72 columns", a
> documentation file was wrapped to 72 rather than 80 characters.  In
> appendix C of the manual on "Tips and Standards" we have "Format the
> documentation string so that it fits within an 80-column screen."  I don't
> think we need to worry about people using terminals that only display 75
> characters anymore.  Even 80 characters is not really an issue anymore.
>
> At any rate, I've had my editor set to wrap code lines at 80 characters for
> years now so there is a lot of the code base that is wrapped to that length
> rather than 72.

I still tend to open terminal windows in a fixed-width font with a size 
of 80 columns and 24 lines.  My Emacs window opens with a fixed-width 
font and a width of 80 characters, though I almost always use more than 
24 lines now.  I can learn new habits and use different sizes.  I don't 
think there is anything magic about 72 or 80 or some other number of 
columns.

Given that I use terminal and editor windows that are 80 columns wide
I have a few reasons for wrapping at less than 80 columns.  One is a 
personal preference, one is a practical issue, and another is somewhere 
in between.

The personal preference is that I think it is easier to read when the 
text stops short of the right margin.  But I don't have a similar 
problem with the text starting all the way over on the left margin of 
the terminal window.  So I probably prefer things this way just because 
I'm used to it.

The practical matter is that Emacs inserts a '\' character at the end of 
wrapped lines as a marker to indicate that the line is long.  So if the 
line is exactly 80 characters wide, Emacs inserts the '\' marker 
character and pushes the last real character to the next the beginning 
of the next line and that's kind of annoying.  Yes, I could disable that 
feature.  Or use a wider terminal.

The other reason is that lines that are too long tend to be hard to 
read.  I would guess that almost no one wants to read lines that are 
1000 or even 500 characters wide.  But exactly where to break the lines 
is a bit of a personal preference.

These days (I mean, since about 1990) with terminals that can be just 
about any size and that can do line breaking between words 
automatically, we probably shouldn't be forcing any line breaks on 
users, or assume that they will be reading in a fixed-width font on any 
particular size terminal window (though we may force a fixed-width font 
for verbatim text, but that's a separate issue).

Maybe the best thing we could do would be to convert the NEWS file and 
other informational documents that we distribute to some format that can 
be viewed properly on whatever output device.  We can still generate and 
provide an old-school text version of the NEWS file with lines wrapped 
to whatever length people think is appropriate.  But then we could also 
automatically generate an HTML or PDF version of the file for the web or 
the GUI that will look good no matter what the width of the terminal or 
browser window is.

As for source files, maybe the suggestion to put "sentences" on single 
lines is worth trying?  In some cases, we would have some very long 
lines (for example, the parameter list of some Fortran functions).  But 
maybe this is not as much of a problem as the constant reformatting due 
to manual line wrapping and the trouble that can cause for diffs.

jwe