Re: cut -DF

[Assaf Gordon]

Hello,

On 2022-01-06 7:35 a.m., Pádraig Brady wrote:
> Thanks for taking the time to consolidate options/functionality
> across different implementations.  This is important for users.
> Some notes below...
>
> On 05/01/2022 16:23, Rob Landley wrote:
> > Around 5 years ago toybox added the -D, -F, and -O options to cut:
> >
> >      -D  Don't sort/collate selections or match -fF lines without 
> > delimiter
> >      -F  Select fields separated by DELIM regex
> >      -O  Output delimiter (default one space for -F, input delim for -f)
>
> As I see it, the main functionalities added here:
>    - reordering of selected fields
>    - adjusted suppression of lines without matching fields
>    - regex delimiter support
>
> I see regex support as less important, but still useful.


Attached is a suggestion for initial implementation of "cut -FDO".
It's split into smaller steps to ease review.

The main issue is that the current "cut_fields" and "cut_bytes" are
highly optimized for speed, so I left them as-is and created a secondary
set of 'cut' functions - slower but with additional options.

If this is acceptable, I'll go on to clean up the patches, add more
tests and write documentation.

There are likely some edge-cases regarding regex matching that need to 
be decided upon (e.g. BRE or ERE, what about BOL/EOL anchors, groups, etc.).

Comments and feedback very welcomed,

regards,
 - assaf

0001-cut-set-fields-add-no-sort-options.patch
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0002-cut-iniitial-D-implmentation-currently-only-with-f.patch
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0003-tests-add-cut-D-tests.patch
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0004-cut-extract-cut-D-f-to-a-separate-function.patch
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0005-cut-implement-D-with-b.patch
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0006-tests-add-cut-D-b-tests.patch
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0007-cut-add-O-short-option-for-output-delimiter.patch
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0008-cut-implement-F.patch
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0009-tests-add-cut-F-tests.patch
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