From: Junio C Hamano <gitster@pobox.com>
To: Atharva Raykar <raykar.ath@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [GSOC][PATCH] userdiff: add support for Scheme
Date: Sun, 28 Mar 2021 11:06:17 -0700 [thread overview]
Message-ID: <xmqqft0fm9uu.fsf@gitster.g> (raw)
In-Reply-To: <EBC020E6-BE8B-4332-8225-A988CB7CFA69@gmail.com> (Atharva Raykar's message of "Sun, 28 Mar 2021 17:21:16 +0530")
Atharva Raykar <raykar.ath@gmail.com> writes:
>>> + "(\\.|[^][)(\\}\\{ ])+"),
>>
>> One or more "dot or anything other than SP or parentheses"? But
>> a dot "." is neither a space or any {bra-ce} letter, so would the
>> above be equivalent to
>>
>> "[^][()\\{\\} \t]+"
>>
>> I wonder...
>
> A backslash is allowed in scheme identifiers, and I erroneously thought that
> the first part handles the case for identifiers such as `component\new` or
> `\"id-with-quotes\"`. (I tested it with a regex engine that behaves differently
> than the one git is using, my bad.)
Ah, perhaps you didn't have enough backslashes. A half of the
doubled one before the dot is eaten by the C compiler, so the regexp
engine is seeing only a single backslash before the dot, which means
"literally a single dot". If you meant "literally a single
backslash, followed by any single char", you probably would write 4
backslashes and a dot---half of the backslashes would be eaten by
the compiler, so you'd be passing two backslashes and a dot, which
is probably what you meant.
Having said that, two further points.
- the "anything but whitespaces and various forms of parentheses"
set would include backslash, so 'component\new' would be taken as
a single word with "[^][()\\{\\} \t]+", wouldn't it?
- how common is the use of backslashes in identifiers? I am trying
to see if the additional complexity needed to support them is
worth the benefit.
> But somehow, the regexp you suggested, ie:
>
> "[^][()\\{\\} \t]+"
>
> does not handle the case of make\foo -> make\bar (it will only diff on foo).
> I am not too sure why it treats backslashes as delimiters.
Perhaps because you have included two backslashes inside [] to say
"backslash is not a word character" in the original, and I blindly
copied that? IOW, do you need to quote {} inside []?
> Yes, this is exactly what I was trying to express. All words should be
> delimited by either whitespace or a parenthesis, and all other special
> characters should be accepted as part of the word.
That sentence after "All words should be..." would be a good comment
to replace what you wrote in the original, then ;-).
next prev parent reply other threads:[~2021-03-28 18:07 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-27 17:39 [GSOC][PATCH] userdiff: add support for Scheme Atharva Raykar
2021-03-27 22:50 ` Junio C Hamano
2021-03-27 23:09 ` Junio C Hamano
2021-03-28 3:16 ` Ævar Arnfjörð Bjarmason
2021-03-28 5:37 ` Junio C Hamano
2021-03-28 12:40 ` Atharva Raykar
2021-03-29 10:08 ` Phillip Wood
2021-03-30 6:41 ` Atharva Raykar
2021-03-30 12:56 ` Ævar Arnfjörð Bjarmason
2021-03-30 13:48 ` Atharva Raykar
2021-03-28 12:45 ` Atharva Raykar
2021-03-28 11:51 ` Atharva Raykar
2021-03-28 18:06 ` Junio C Hamano [this message]
2021-03-29 8:12 ` Atharva Raykar
2021-03-29 20:47 ` Junio C Hamano
2021-03-29 10:12 ` Phillip Wood
2021-03-27 23:46 ` Johannes Sixt
2021-03-28 12:23 ` Atharva Raykar
2021-03-29 10:18 ` Phillip Wood
2021-03-29 10:48 ` Johannes Sixt
2021-03-29 13:12 ` Ævar Arnfjörð Bjarmason
2021-03-29 14:06 ` Phillip Wood
2021-03-30 7:04 ` Atharva Raykar
2021-03-30 10:22 ` Atharva Raykar
2021-04-05 10:04 ` Phillip Wood
2021-04-05 17:58 ` Johannes Sixt
2021-04-06 12:29 ` Atharva Raykar
2021-04-06 19:10 ` Phillip Wood
2021-04-03 13:16 ` [GSoC][PATCH v2 0/1] userdiff: add support for scheme Atharva Raykar
2021-04-03 13:16 ` [GSoC][PATCH v2 1/1] " Atharva Raykar
2021-04-05 10:21 ` Phillip Wood
2021-04-06 10:32 ` Atharva Raykar
2021-04-08 9:14 ` [GSoC][PATCH v3 0/1] " Atharva Raykar
2021-04-08 9:14 ` [GSoC][PATCH v3 1/1] userdiff: add support for Scheme Atharva Raykar
2021-04-12 23:04 ` Junio C Hamano
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