Re: Adjacent string literals

From	Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups	comp.std.c
Subject	Re: Adjacent string literals
Date	2021-01-26 13:05 -0800
Organization	None to speak of
Message-ID	<87o8hb76jb.fsf@nosuchdomain.example.com> (permalink)
References	<rumnae$4mr$1@dont-email.me> <874kj3x4yr.fsf@bsb.me.uk> <6tCdnX0audEHko39nZ2dnUU78VHNnZ2d@giganews.com>

Show all headers | View raw

Jakob Bohm <jb-usenet@wisemo.com.invalid> writes:
> On 2021-01-26 13:22, Ben Bacarisse wrote:
>> James Kuyper <jameskuyper@alumni.caltech.edu> writes:
>>
>>> I learned a couple of decades ago that adjacent string literals get
>>> concatenated into a single longer literal, even if separated by
>>> arbitrarily large amounts of white-space.
>>>
>>> Yesterday I happened to notice that translation phase 6 says only that
>>> "Adjacent string literal tokens are concatenated.", without saying
>>> anything about white-space. White-space doesn't lose it's significance
>>> until translation phase 7. Therefore, string literals that are separated
>>> by white-space do not qualify as adjacent. There's also no mention of
>>> white-space in the fuller discussion that occurs in 6.4.5p5.
>>>
>>> Am I missing something obvious here? I can imagine someone telling me
>>> that "adjacent" should be understood as "adjacent, ignoring white-space"
>>> - but that doesn't seem obvious to me.
>>
>> Surely it just means "next to", and in the sequence of tokens "a" "b"
>> the two are next to each other.  It happens that string literal tokens
>> are such that they can be adjacent without having any white-space
>> between then, but I suspect that's making you over-think the meaning.
>> Would you say that 'long int x' has no tokens adjacent to any others?
>
> The interesting situation is cases like these:
>
> "a" /* Long comment explaining why b is the next byte */ "b"
>
> And
>
> #define LEAD_BYTE  "a"
> #define TRAIL_BYTE "b"
>
> LEAD_BYTE TRAIL_BYTE

Sorry, but those cases aren't particularly interesting.  Comments are
replaced by spaces in translation phase 3, and macros are expanded in
phase 4.  Adjacent string literals are concatenated in phase 6.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips Healthcare
void Void(void) { Void(); } /* The recursive call of the void */

Thread

Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-01-25 10:15 -0500
  Re: Adjacent string literals Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-01-26 12:22 +0000
    Re: Adjacent string literals Jakob Bohm <jb-usenet@wisemo.com.invalid> - 2021-01-26 13:48 +0100
      Re: Adjacent string literals Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-01-26 13:05 -0800
      Re: Adjacent string literals Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-01-26 21:40 +0000
        Re: Adjacent string literals Jakob Bohm <jb-usenet@wisemo.com.invalid> - 2021-01-28 09:53 +0100
          Re: Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-01-28 05:45 -0500
    Re: Adjacent string literals Richard Damon <Richard@Damon-Family.org> - 2021-01-26 07:52 -0500
    Re: Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-01-26 09:29 -0500
      Re: Adjacent string literals Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-01-26 21:46 +0000
        Re: Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-01-26 18:28 -0500
          Re: Adjacent string literals Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-01-27 01:16 +0000
            Re: Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-01-26 22:48 -0500
              Re: Adjacent string literals Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-01-27 15:46 +0000
                Re: Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-01-27 11:20 -0500
                Re: Adjacent string literals Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-01-28 03:05 +0000
  Re: Adjacent string literals Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-10 08:49 -0700
    Re: Adjacent string literals Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-07-10 14:58 -0700
      Re: Adjacent string literals Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-22 10:29 -0700
    Re: Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-11 11:41 -0700
      Re: Adjacent string literals Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-22 15:26 -0700
        Re: Adjacent string literals James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-22 17:29 -0700
          Re: Adjacent string literals Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-17 05:29 -0800

csiph-web