options to suppress and or tabularize line numbers

[n1vux]

Per ack-users thread this day c/o Matt Thompson

Consider --[no-?]line-number and --initial-tab for tabular neatness.

I note that Gnu Grep has ​-T​ ​--initial-tab​​ to insert tab after Line Number to make alignments work but does not support the obvious ​--no-line-number override (possibly as --no-filename will do that in the only case that matters for them? ).

(Right aligning line numbers could also tabularize, but too many edge cases.)

[andrewblack]

Like the sound of this (once hacked ack1 to do something similar). Was working on a codebase with a lot of embedded SWIFT messages in test suite. Putting a line number and : straight before a line beginning ":20:" wasn't fun!

[mathomp4]

(Matt Thompson from ack-users here. Forgot about github issues...sorry!)

Huh. Just had to say I'd never heard of --initial-tab. I'd always pipe'd the grep to awk. Even though I use ack almost exclusively, it still teaches me!

[n1vux]

(re sorry, it is ok to raise a question on ack-users and let someone who knows the code write an issue only if there isn't an easy user-space answer ! )

AFAIK, --initial-tab is a Gnu-ish extension, not Bell/POSIX, so not officially standard, so not surprised you hadn't seen it either -- only found it when i was looking to see if they had --no-line-number (no!). ( I was looking because we do try to support grep flags as appropriate under the least-surprise principle. )

[andrewblack]

I am not terribly keen on putting a tab in, and would like the number right justified. My suggestion would be an option --number-format

• no param - space fill to 8 chars.
• para - as sprintf format for displaying number and the ":' . For example "%-5d%s "

Or is that too complex.

On 2 December 2014 at 16:59, Bill Ricker notifications@github.com wrote:

(re sorry, it is ok to raise a question on ack-users and let someone who knows the code write an issue only if there isn't an easy user-space answer ! )

AFAIK, --initial-tab is a Gnu-ish extension, not Bell/POSIX, so not officially standard, so not surprised you hadn't seen it either -- only found it when i was looking to see if they had --no-line-number (no!). ( I was looking because we do try to support grep flags as appropriate under the least-surprise principle. )

— Reply to this email directly or view it on GitHub https://github.com/petdance/ack2/issues/517#issuecomment-65264282.

[n1vux]

Andrew - I'd like to be able to offer multiple options. Tab is one option, good for some uses - particularly if data contains tabs; suppress numbers is another. Enhancing line # formatting options would be a third. DWIM and TIMTOWTDI are our Perl mottos, so more is better.

In "%-5d%s ", are you suggesting the %s positions the (possibly colorized) line, or just the colon? I'd suggest the colon be a literal in "%-5d :" or "%8d\t" , if going sprintf route.

Formatting the number is adding much complexity.
We already have -o, --output which can do some primitive concatenation formating of literals with special variables $. $$& $' $_ $1 $2 etc. (With tabs, the deprecated $ $& $' would make for a KWIC index.)
But it doesn't allow calling sprintf(). Combining a sprintf-ish option for fancy formatting (right justified or zero filled) with a selection of matchvars without introducing a general turing machine security hole would be a problem. And then there's formatting filename:line when filename is on the line. But allowing formatting of line # only if NOT adjusting rest of line seems stilted.

An option to force line numbers to zero fill to a (default) width of 8 might be easier than general case. Perl code would be like ($line_no_width ? sprintf (q(%0*2$d), $line_no, $line_no_width) : $line_no ) (where $line_no_width is probably buried in the option hash ref), likely in the print_line_with_options() subroutine.

[petdance]

Closed and moved to wiki.