Date: Fri, 10 Aug 2001 20:48:39 -0400 From: Jan Knepper <jan@digitaldaemon.com> To: FreeBSD Hackers <hackers@freebsd.org> Subject: Re: the =+ operator Message-ID: <3B7480E7.6070406@digitaldaemon.com> References: <3B73F0BC.548D40B3@home.com> <3B73F595.CD12F8AA@mitre.org> <3B747B35.CCA4C6D1@home.com>
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I just checked on this "=+" and "=-" with the guy that wrote the first
native C++ compiler and he does not recall it at first being that way...
I have been programming C++ myself for over 10 years and *never* heard
this before. I do not know where it comes from. It might have been some
mis-implemented C++ syntax in other C++ compilers (GNU?). Need less to
say, '=+' as operator would be scary as it is too close to '= +' as in
a=+5 or a=-5 for that matter. I have too much respect for Bjarne to
think that he would have defined it as '=+' and '=-' in the beginning...
Just my two cents.
Jan
Rob wrote:
>Mike Smith wrote:
>
>>I've been doing this for a long time and today this would be taken as
>>two operators. The assignment and unary +. Since A = B is the same as A
>>= +B, it would perform the same as a simple assignment. The only reason
>>I can see to do this legitimately is for clarity reasons, i.e., if what
>>follows the "+" is almost always used as a negative but this use is an
>>exception. But more likely, at some point there was something between
>>the = and + at one point that got deleted, but the "+" was left. Since
>>this is "the default", there would be no coding or operational errors
>>from leaving it in.
>>
>>Then again, it could have been intended to be += and you've found a
>>heretofore undiscovered bug! All you have to do is press Shift at the
>>wrong time (not that I've ever done that).
>>
>>Mike Smith
>>(but not "THE" Mike Smith)
>>
>>Rob wrote:
>>
>>>My first post on hackers, so please don't flame me too bad :) I think
>>>that only an old hacker can give me the answer :)
>>>
>>>I've searched far and wide on search engines to find out what the =+
>>>operator does, to no avail. I'm porting some old code and found it. I
>>>made a test program and compiled it with gcc, and all it appears to do
>>>is the same as regular assignment. But I'm wondering if in some day
>>>long ago, it mean't something else? Thanks, Rob.
>>>
>>>To Unsubscribe: send mail to majordomo@FreeBSD.org
>>>with "unsubscribe freebsd-hackers" in the body of the message
>>>
>
>Thanks Mike, also thanks for everyone elses response. This code is
>actually pretty new. It part of a bi-gradient conjugate solver for FEM
>simulators. I compiled the original code with gcc, so I'm assuming it
>just treated =+ as an =. But just for kicks I also tried +=. In any
>case I have some other bugs in it that I have to track down since
>no-matter which way I tried the assignment, my solutions fail to
>converge :( Rob.
>
>To Unsubscribe: send mail to majordomo@FreeBSD.org
>with "unsubscribe freebsd-hackers" in the body of the message
>
>
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I just checked on this "=+" and "=-" with the guy that wrote the first native
C++ compiler and he does not recall it at first being that way... I have
been programming C++ myself for over 10 years and *never* heard this before.
I do not know where it comes from. It might have been some mis-implemented
C++ syntax in other C++ compilers (GNU?). Need less to say, '=+' as operator
would be scary as it is too close to '= +' as in a=+5 or a=-5 for that matter.
I have too much respect for Bjarne to think that he would have defined it
as '=+' and '=-' in the beginning...<br>
<br>
Just my two cents.<br>
Jan<br>
<br>
<br>
<br>
Rob wrote:<br>
<blockquote type="cite" cite="mid:3B747B35.CCA4C6D1@home.com">
<pre wrap="">Mike Smith wrote:<br></pre>
<blockquote type="cite">
<pre wrap="">I've been doing this for a long time and today this would be taken as<br>two operators. The assignment and unary +. Since A = B is the same as A<br>= +B, it would perform the same as a simple assignment. The only reason<br>I can see to do this legitimately is for clarity reasons, i.e., if what<br>follows the "+" is almost always used as a negative but this use is an<br>exception. But more likely, at some point there was something between<br>the = and + at one point that got deleted, but the "+" was left. Since<br>this is "the default", there would be no coding or operational errors<br>from leaving it in.<br><br>Then again, it could have been intended to be += and you've found a<br>heretofore undiscovered bug! All you have to do is press Shift at the<br>wrong time (not that I've ever done that).<br><br>Mike Smith<br>(but not "THE" Mike Smith)<br><br>Rob wrote:<br></pre>
<blockquote type="cite">
<pre wrap="">My first post on hackers, so please don't flame me too bad :) I think<br>that only an old hacker can give me the answer :)<br><br>I've searched far and wide on search engines to find out what the =+<br>operator does, to no avail. I'm porting some old code and found it. I<br>made a test program and compiled it with gcc, and all it appears to do<br>is the same as regular assignment. But I'm wondering if in some day<br>long ago, it mean't something else? Thanks, Rob.<br><br>To Unsubscribe: send mail to <a class="moz-txt-link-abbreviated" href="mailto:majordomo@FreeBSD.org">majordomo@FreeBSD.org</a><br>with "unsubscribe freebsd-hackers" in the body of the message<br></pre>
</blockquote>
</blockquote>
<pre wrap=""><!----><br>Thanks Mike, also thanks for everyone elses response. This code is<br>actually pretty new. It part of a bi-gradient conjugate solver for FEM<br>simulators. I compiled the original code with gcc, so I'm assuming it<br>just treated =+ as an =. But just for kicks I also tried +=. In any<br>case I have some other bugs in it that I have to track down since<br>no-matter which way I tried the assignment, my solutions fail to<br>converge :( Rob.<br><br>To Unsubscribe: send mail to <a class="moz-txt-link-abbreviated" href="mailto:majordomo@FreeBSD.org">majordomo@FreeBSD.org</a><br>with "unsubscribe freebsd-hackers" in the body of the message<br><br><br></pre>
</blockquote>
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