Request: no-mixed-spaces mode

[cxw42]

Please see attached foo.txt. Line 2 has fifteen leading spaces. Running

wtf -v -s -y 8 foo.txt | xxd -g1

changes the first 8 spaces to a tab and leaves the last 7 spaces:

	CHANGED 8 spaces to tabs on 1 lines
00000000: 30 31 32 33 34 35 36 37 38 39 61 62 63 64 65 66  0123456789abcdef
00000010: 0a 09 20 20 20 20 20 20 20 68 65 6c 6c 6f 21 0a  ..       hello!.

I would like to request a mode in which any trailing group of spaces after a leading group of tabs would be converted to a single tab. Unlike -y N, this would convert every group of up to N spaces to a tab.

The use case is Linux kernel coding, which uses hard tabs. I care more about consistency than exact-column indentation. clang-format will give me tab+space mix, and I'd like to use wtf to convert those last few spaces to one additional tab per line.

Thanks for considering this request!

[dlenski]

Unlike -y N, this would convert every group of up to N spaces to a tab.

So how would you handle (say) a line that started with "\t \t "? Would that get converted to two tabs or 3 or 4? How about " \t \t"?

The use case is Linux kernel coding, which uses hard tabs.

Last time I checked, Linux kernel devs want hard tabs for offsetting indented blocks (so that individual devs can customize their width), and spaces for matching continuation lines (visually lining up), e.g.

if (condition) {
\tfunction_with_long_arguments(first_arg, second_arg.
\t                             this_third_arg_should_be_indented_with_spaces)
}

If you change those spaces on the second line to tabs, I expect you're gonna get your patches rejected.

Once you decide how to resolve the ambiguity, and if you still want it… this should be easy to implement. Patches welcome :)

[cxw42]

"\t \t "

Good question! I hadn't thought about that. If it were me, I would expand the tabs to N spaces, then reslice from the beginning. So "\t \t " with N=8 would become 18 spaces -> 3 tabs.

matching continuation lines

I've seen some of that code as well. I'm trying to be a good corporate citizen (as it were) and follow statements like "spaces are never used for indentation" here and "[l]ine up argument lists by tabs, not spaces" here. If you know other guidance overriding those, please let me know!