On 16 April 2013 15:04, Glenn Fowler <[email protected]> wrote:
>
> thanks for the report
> the work adding -C was apparently interrupted a while back
> its on the todo list
>
> this is not an easy fix for ast grep because the fast inner loop matches
> buffers containing multiple lines and does not parse line structure until
> a match is found
>
> the only time single lines are matched is when lines cross buffer boundaries
>
> mmap()ing the entire file (topic under discussion) would make it easy but
> would not help the very common input from pipe case
>
> On Tue, 16 Apr 2013 11:05:10 +0200 Wendy Lin wrote:
>> On 13 April 2013 16:05, Wendy Lin <[email protected]> wrote:
>> > Dear ast-devel,
>> >
>> > the grep -C from the latest ast-ksh (2013-04-09) does not work
>> > compared to GNU grep 2.14
>> >
>> > In GNU grep 2.14 I get this for the context option:
>> >
>> > seq 200 >"测试文件"
>> > ksh -c '/usr/bin/grep --context=2 51 <"测试文件"'
>> > 49
>> > 50
>> > 51
>> > 52
>> > 53
>> > --
>> > 149
>> > 150
>> > 151
>> > 152
>> > 153
>> >
>> > But I get this from grep from ast-ksh for the context option:
>> >
>> > ksh -c 'builtin grep ; grep --context=2 51 <"测试文件"'
>> > 51
>> > 151
>> >
>> > Is this a bug or feature?
>> >
>> > AFAIK the -C option in ast-ksh grep should work like this:
>> > -C 2 gives 2 lines of context before and after the match
>> > -C ,2 gives only 2 lines of context after the match
>> > -C 2, gives only 2 lines of contetxt before the match
>> >
>> > optionally AST grep should support these two long options for GNU grep
>> > compatibility:
>> >
>> >   --before-context=NUM  print NUM lines of leading context
>> >   --after-context=NUM   print NUM lines of trailing context
>> >
>> > What do you think?
>
>> Was the bug report received?
>> >
>> > Wendy

Glenn, how long will it take to get grep -C implemented?

Wendy
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