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Re: Command Languages Versus Programming Languages

From cross@spitfire.i.gajendra.net (Dan Cross)
Newsgroups comp.unix.shell, comp.unix.programmer, comp.lang.misc
Subject Re: Command Languages Versus Programming Languages
Date 2024-11-22 18:12 +0000
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <vhqhii$d5e$1@reader2.panix.com> (permalink)
References <uu54la$3su5b$6@dont-email.me> <877c8vtgx6.fsf@doppelsaurus.mobileactivedefense.com> <vhqebq$c71$1@reader2.panix.com> <87o727rwga.fsf@doppelsaurus.mobileactivedefense.com>

Cross-posted to 3 groups.

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In article <87o727rwga.fsf@doppelsaurus.mobileactivedefense.com>,
Rainer Weikusat  <rweikusat@talktalk.net> wrote:
>>>Something which would match [0-9]+ in its first argument (if any) would
>>>be:
>>>
>>>#include "string.h"
>>>#include "stdlib.h"
>>>
>>>int main(int argc, char **argv)
>>>{
>>>    char *p;
>>>    unsigned c;
>>>
>>>    p = argv[1];
>>>    if (!p) exit(1);
>>>    while (c = *p, c && c - '0' > 10) ++p;
>>>    if (!c) exit(1);
>>>    return 0;
>>>}
>>>
>>>but that's 14 lines of text, 13 of which have absolutely no relation to
>>>the problem of recognizing a digit.
>>
>> This is wrong in many ways.  Did you actually test that program?
>>
>> First of all, why `"string.h"` and not `<string.h>`?  Ok, that's
>> not technically an error, but it's certainly unconventional, and
>> raises questions that are ultimately a distraction.
>
>Such as your paragraph above. 
>
>> Second, suppose that `argc==0` (yes, this can happen under
>> POSIX).
>
>It can happen in case of some piece of functionally hostile software
>intentionally creating such a situation. Tangential, irrelevant
>point. If you break it, you get to keep the parts.
>
>> Third, the loop: why `> 10`? Don't you mean `< 10`?  You are
>> trying to match digits, not non-digits.
>
>Mistake I made. The opposite of < 10 is > 9.

I see.  So you want to skip non-digits and exit the first time
you see a digit.  Ok, fair enough, though that program has
already been written, and is called `grep`.

>> Fourth, you exit with failure (`exit(1)`) if `!p` *and* if `!c`
>> at the end, but `!c` there means you've reached the end of the
>> string; which should be success.
>
>Mistake you made: [0-9]+ matches if there's at least one digit in the
>string. That's why the loop terminates once one was found. In this case,
>c cannot be 0.

Ah, you are trying to match `[0-9]` (though you're calling it
`[0-9]+`).  Yeah, your program was not at all equivalent to one
I wrote, though this is what you posted in response to mine, so
I assumed you were trying to emulate that behavior (matching
`^[0-9]+$`).

But I see above that you mentioned `[0-9]+`.  But as I mentioned
above, really you're just matching any digit, so you may as well
be matching `[0-9]`; again, this not the same as the actual
regexp, because you are ignoring the semantics of what regular
expressions actually describe.

In any event, this seems simpler than what you posted:

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>

int
main(int argc, char *argv[])
{
        if (argc != 2) {
                fprintf(stderr, "Usage: matchd <str>\n");
                return EXIT_FAILURE;
        }

        for (const char *p = argv[1]; *p != '\0'; p++)
                if ('0' <= *p && *p <= '9')
                        return EXIT_SUCCESS;

        return EXIT_FAILURE;
}

	- Dan C.

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Thread

Re: Command Languages Versus Programming Languages Bozo User <anthk@disroot.org> - 2024-09-30 20:04 +0000
  Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-09-30 21:04 +0000
    Re: Command Languages Versus Programming Languages usuario <anthk@disroot.org> - 2024-10-01 20:18 +0000
      Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-02 07:10 +0000
        Re: Command Languages Versus Programming Languages usuario <anthk@disroot.org> - 2024-10-02 12:52 +0000
          Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-02 16:00 +0000
  Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-09 22:25 +0100
    Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-10 08:38 +0000
      Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-10 16:09 +0100
        Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-10 15:34 +0000
          Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-10 17:55 +0100
            Re: Command Languages Versus Programming Languages Kaz Kylheku <643-408-1753@kylheku.com> - 2024-10-10 19:14 +0000
              Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-10 21:31 +0100
                Re: Command Languages Versus Programming Languages Bart <bc@freeuk.com> - 2024-10-11 00:09 +0100
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-11 15:47 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-11 15:15 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-11 15:45 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-11 15:59 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-11 16:28 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-12 08:39 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-12 13:53 +0000
                Re: Command Languages Versus Programming Languages Muttley@dastardlyhq.com - 2024-10-12 14:50 +0000
                Re: Command Languages Versus Programming Languages scott@slp53.sl.home (Scott Lurndal) - 2024-10-12 15:32 +0000
                Re: Command Languages Versus Programming Languages Muttley@dastardlyhq.com - 2024-10-12 15:51 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-12 16:36 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-13 08:18 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-13 13:43 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-13 14:54 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-13 15:30 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-13 16:02 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-13 20:15 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-14 08:25 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-14 13:38 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-14 14:47 +0000
                Re: Command Languages Versus Programming Languages scott@slp53.sl.home (Scott Lurndal) - 2024-10-14 14:53 +0000
                Re: Command Languages Versus Programming Languages David Brown <david.brown@hesbynett.no> - 2024-10-14 17:27 +0200
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-13 21:09 +0000
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-13 21:08 +0000
                Re: Command Languages Versus Programming Languages scott@slp53.sl.home (Scott Lurndal) - 2024-10-13 15:08 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-13 15:52 +0000
                Re: Command Languages Versus Programming Languages Bart <bc@freeuk.com> - 2024-10-13 17:20 +0100
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-13 20:29 +0000
                Re: Command Languages Versus Programming Languages Bart <bc@freeuk.com> - 2024-10-14 01:20 +0100
                Re: On overly rigid definitions (was Re: Command Languages Versus Programming Languages) cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-14 00:58 +0000
                Re: Command Languages Versus Programming Languages scott@slp53.sl.home (Scott Lurndal) - 2024-10-13 15:02 +0000
                Re: Command Languages Versus Programming Languages Kaz Kylheku <643-408-1753@kylheku.com> - 2024-10-13 16:31 +0000
                Re: Command Languages Versus Programming Languages Bart <bc@freeuk.com> - 2024-10-13 20:06 +0100
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-10-13 20:30 +0000
                Re: Command Languages Versus Programming Languages scott@slp53.sl.home (Scott Lurndal) - 2024-10-11 16:37 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-11 19:01 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-12 08:40 +0000
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-11 20:58 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-12 08:42 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-12 14:37 +0100
                Re: Command Languages Versus Programming Languages Christian Weisgerber <naddy@mips.inka.de> - 2024-10-12 17:49 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-13 08:20 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-13 21:25 +0100
                Re: Command Languages Versus Programming Languages Bart <bc@freeuk.com> - 2024-10-12 20:50 +0100
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-12 21:25 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-13 08:22 +0000
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-13 20:33 +0000
            Re: Command Languages Versus Programming Languages Bart <bc@freeuk.com> - 2024-10-11 00:07 +0100
              Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-11 16:15 +0100
            Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-11 08:17 +0000
              Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-11 19:37 +0100
          Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-11 01:33 +0000
        Re: Command Languages Versus Programming Languages Eric Pozharski <apple.universe@posteo.net> - 2024-10-12 16:39 +0000
          Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-13 08:19 +0000
            Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-10-13 14:55 +0200
            Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-13 21:33 +0100
              Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-14 08:28 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-14 11:38 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-14 11:05 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-10-14 16:04 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-10-14 15:39 +0000
            Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-13 20:34 +0000
      Re: Command Languages Versus Programming Languages Sebastian <sebastian@here.com.invalid> - 2024-11-11 07:31 +0000
        Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-11 10:06 +0000
          Re: Command Languages Versus Programming Languages Wolfgang Agnes <wagnes@jemoni.to> - 2024-11-11 08:28 -0300
            Re: Command Languages Versus Programming Languages Muttley@dastardlyhq.com - 2024-11-11 16:21 +0000
          Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-11 20:55 +0000
          Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-12 10:14 +0100
            Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-12 09:21 +0000
              Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-12 10:31 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-12 09:53 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-12 15:05 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-12 15:09 +0000
              Re: Command Languages Versus Programming Languages Wolfgang Agnes <wagnes@jemoni.to> - 2024-11-12 13:47 -0300
        Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-11 21:24 +0000
          Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-12 10:23 +0100
            Re: Command Languages Versus Programming Languages Wolfgang Agnes <wagnes@jemoni.to> - 2024-11-12 13:50 -0300
            Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-12 20:29 +0000
          Re: Command Languages Versus Programming Languages merlyn@stonehenge.com (Randal L. Schwartz) - 2024-11-19 18:43 -0800
            Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-20 04:34 +0000
            Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-20 08:21 +0000
              Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-20 11:51 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-20 11:30 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-20 16:38 +0100
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-20 16:38 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-20 17:54 +0000
                Re: Command Languages Versus Programming Languages John Ames <commodorejohn@gmail.com> - 2024-11-20 10:03 -0800
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-21 08:18 +0000
                Re: Command Languages Versus Programming Languages John Ames <commodorejohn@gmail.com> - 2024-11-21 07:56 -0800
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-21 14:13 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-21 16:06 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-21 08:13 +0000
                Re: Command Languages Versus Programming Languages John Ames <commodorejohn@gmail.com> - 2024-11-21 07:58 -0800
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-20 17:50 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-21 14:40 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-21 15:07 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 13:30 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 15:41 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 15:52 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 17:18 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 17:35 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 17:43 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 17:43 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 17:17 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 17:48 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 18:12 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 18:48 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 19:05 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 19:24 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 19:46 +0000
                Re: Command Languages Versus Programming Languages scott@slp53.sl.home (Scott Lurndal) - 2024-11-22 18:14 +0000
                Re: Command Languages Versus Programming Languages scott@slp53.sl.home (Scott Lurndal) - 2024-11-22 18:22 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 18:30 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 18:59 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 19:15 +0000
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 19:26 +0000
                Re: Command Languages Versus Programming Languages cross@spitfire.i.gajendra.net (Dan Cross) - 2024-11-22 19:51 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-22 12:14 +0100
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-22 11:56 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-22 20:33 +0100
                Re: Command Languages Versus Programming Languages Kaz Kylheku <643-408-1753@kylheku.com> - 2024-11-21 19:12 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-22 10:09 +0000
                Re: Command Languages Versus Programming Languages Kaz Kylheku <643-408-1753@kylheku.com> - 2024-11-22 18:18 +0000
                Re: Command Languages Versus Programming Languages Muttley@dastardlyhq.com - 2024-11-23 11:40 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-22 12:17 +0100
                Re: Command Languages Versus Programming Languages Kaz Kylheku <643-408-1753@kylheku.com> - 2024-11-22 18:19 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-22 20:20 +0100
              Re: Command Languages Versus Programming Languages Ed Morton <mortonspam@gmail.com> - 2024-11-20 05:46 -0600
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-20 12:27 +0000
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-20 21:43 +0000
                Re: Command Languages Versus Programming Languages Muttley@DastartdlyHQ.org - 2024-11-21 08:15 +0000
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-21 22:05 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-22 12:47 +0100
                Re: Command Languages Versus Programming Languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-22 20:41 +0000
                Re: Command Languages Versus Programming Languages Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-11-20 16:53 +0100
                Re: Command Languages Versus Programming Languages Ed Morton <mortonspam@gmail.com> - 2024-11-23 18:17 -0600
              Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-20 12:21 +0000
                Re: Command Languages Versus Programming Languages merlyn@stonehenge.com (Randal L. Schwartz) - 2024-11-21 05:38 -0800
                Re: Command Languages Versus Programming Languages Rainer Weikusat <rweikusat@talktalk.net> - 2024-11-21 17:01 +0000

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