220 40961 article Path: news.gmane.org!.POSTED!not-for-mail From: Brian Bi Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Can we have beginner friendly new line and deprecate std::endl? Date: Sun, 11 Nov 2018 16:38:15 -0500 Lines: 347 Approved: news@gmane.org Message-ID: References: <7da1f33f-c2c1-482f-8fc2-c23a9767a5ec@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="000000000000ad2b00057a6a6797" X-Trace: blaine.gmane.org 1541972188 11735 195.159.176.226 (11 Nov 2018 21:36:28 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 11 Nov 2018 21:36:28 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDS5ZX5VU4NBBVOCULPQKGQEODHALPA@isocpp.org Sun Nov 11 22:36:24 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ed1-f69.google.com ([209.85.208.69]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gLxP1-0002sI-Eg for gclcip-std-proposals@m.gmane.org; Sun, 11 Nov 2018 22:36:19 +0100 Original-Received: by mail-ed1-f69.google.com with SMTP id c12-v6sf3832419ede.6 for ; Sun, 11 Nov 2018 13:38:30 -0800 (PST) ARC-Seal: i=2; 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[209.85.220.41]) by mx.google.com with SMTPS id y19-v6sor7322878edt.14.2018.11.11.13.38.28 for (Google Transport Security); Sun, 11 Nov 2018 13:38:28 -0800 (PST) Received-SPF: pass (google.com: domain of bbi5291@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 2002:a50:ce5e:: with SMTP id k30-v6mr9821064edj.207.1541972308075; Sun, 11 Nov 2018 13:38:28 -0800 (PST) In-Reply-To: <7da1f33f-c2c1-482f-8fc2-c23a9767a5ec@isocpp.org> X-Original-Sender: bbi5291@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=eqfzdfuh; spf=pass (google.com: domain of bbi5291@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=bbi5291@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:40961 Archived-At: --000000000000ad2b00057a6a6797 Content-Type: text/plain; charset="UTF-8" On Sat, Nov 10, 2018 at 10:24 AM wrote: > > > On Friday, November 9, 2018 at 6:50:59 PM UTC+2, Brian Bi wrote: >> >> >> >> On Fri, Nov 9, 2018 at 3:19 AM wrote: >> >>> There are multiple problems with '\n' >>> >>> First - it is ultimately C ("way") >>> >> This mailing list is about C++, not Java, Rust, Swift, etc. >> This is not an argument. >> > > There is some sort of miscommunication. > The fact there no C++ way to insert a new line (only a UNIX special > character way) is what I state an issue, > considering the rest of the API > '\n' is standard C, which became standard C++ about 20 years ago. I don't see the issue. > > >> >> Second, when we introduce simple output to beginners, for which cout is >>> actually good because of overloading, >>> when using '\n' we have to introduce additional topics >>> - the fact a char can be more the one, well, character >>> - special magic characters >>> We also create asymmetry b/w what is used to start the output std::cout >>> (an object), to modify it (hex) and what is used to end it ("magic"). >>> >> > >> What do you mean, "what is used to end it"? A semicolon? >> > > std::cout //< start > << 12.f > << ' ' > << std::hex //< modify > << 255 > << '\n'; //< finish (magic) > > Note that printf (and other languages) already use special characters to > modify the output, so having an '\n' is not abrupt. > > But C++ streams are different, having to spell out a special character is > odd and unintuitive for a beginner and a design deficiency in general. > It's only "magic" if you teach beginners that '\n' is a special magic command, rather than the literal representation of the newline character. > > > > >> >>> >>> This screams some design flaw - we should be able to insert a new lines >>> the same way we modify the stream! >>> >> Yes, the way to do that is with '\n'. >> >> >>> >>> On its own std::endl has the flaw that it does not obey the "do one >>> thing" rule. >>> Once we deprecate it, this will shut down all the naive >>> tutorials/courses still teaching it as the default! >>> >>> >>> As for std::newline, we have options - >>> >>> std::nl //< even a beginner can "read" it >>> std::newl //< orthogonal to endl >>> std::br //< why not at this point! >>> std::brl >>> std::bl >>> >>> Geeks can still use `\n`, but a beginner (and a teacher) will have a >>> simple, *correct, *go-to option that models the syntax already >>> introduced (std::cout)! >>> >>> >>> On Friday, November 9, 2018 at 8:22:26 AM UTC+2, PeterSommerlad wrote: >>>> >>>> So the better way is do better teaching. I show my students that they >>>> should not use endl, except when they need it. >>>> >>>> Sent from Peter Sommerlad's iPad >>>> +41 79 432 23 32 >>>> >>>> On 8 Nov 2018, at 23:43, Hyman Rosen wrote: >>>> >>>> On Thu, Nov 8, 2018 at 5:08 PM Brian Bi wrote: >>>> >>>>> I think the reason why novices use std::endl is that they're under the >>>>> impression (no doubt perpetuated by incompetent educators) that std::endl >>>>> is portable whereas '\n' isn't. >>>>> >>>> >>>> I think novices use std::endl because that's how C++ formatted I/O >>>> was presented for ages. I have the feeling, completely unsupported >>>> by evidence, that the iostreams designers thought manipulators were >>>> really keen, and wanted to have one that would always get used. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "ISO C++ Standard - Future Proposals" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to std-proposal...@isocpp.org. >>>> To post to this group, send email to std-pr...@isocpp.org. >>>> To view this discussion on the web visit >>>> https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAHSYqdYYZjeHHbRZ5bcHLYVsWfspwCeQ8oxEDRbuJ8dqAtsX5A%40mail.gmail.com >>>> >>>> . >>>> >>>> -- >>> You received this message because you are subscribed to the Google >>> Groups "ISO C++ Standard - Future Proposals" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to std-proposal...@isocpp.org. >>> To post to this group, send email to std-pr...@isocpp.org. >>> To view this discussion on the web visit >>> https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/b49f4c85-816b-4b35-851d-407061a8ef9f%40isocpp.org >>> >>> . >>> >> >> >> -- >> *Brian Bi* >> > -- > You received this message because you are subscribed to the Google Groups > "ISO C++ Standard - Future Proposals" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to std-proposals+unsubscribe@isocpp.org. > To post to this group, send email to std-proposals@isocpp.org. > To view this discussion on the web visit > https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/7da1f33f-c2c1-482f-8fc2-c23a9767a5ec%40isocpp.org > > . > -- *Brian Bi* -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAMmfjbMHae%3DpbG7LMjjjqWAE-5Zaiwi3rpWXr-HpwBRo0bjvfA%40mail.gmail.com. --000000000000ad2b00057a6a6797 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Sat, Nov 10= , 2018 at 10:24 AM <mihailna= jdenov@gmail.com> wrote:


On Friday, November 9, 2018 at 6:50:59 PM UTC+2, Bria= n Bi wrote:

On Fri, Nov 9, 2018 at 3:19 AM= <mihailn...@gmail.com> wrote:
There are multiple problems with= '\n'

First - it is ultimately C ("way"= ;)
This mailing list is about C++, not Java, R= ust, Swift, etc.
This is not an argument.

There is some sort of miscommunication.=C2=A0
The fact there no C++ way to insert a new line (only a UNIX special= character way) is what I state an issue,=C2=A0
considering the r= est of the API=C2=A0

'\n= 9; is standard C, which became standard C++ about 20 years ago. I don't= see the issue.
=C2=A0
=C2=A0

Second, when we introduce simple output= to beginners, for which cout is actually good because of overloading,
when using '\n' we have to introduce additional topics=C2=A0<= br>
=C2=A0- the fact a char can be more the one, well, character
<= div>=C2=A0- special magic characters
We also create asymmetry b/w= what is used to start the output std::cout (an object), to modify it (hex)= and what is used to end it ("magic").
=C2=A0
What do you mea= n, "what is used to end it"? A semicolon?

std::= cout=C2=A0 =C2=A0 =C2=A0//< start=C2=A0
=C2=A0 << 12.f=C2=A0
=C2=A0 << ' '=C2=A0
=C2=A0 << std::hex //<= modify
=C2=A0 <&= lt; 255
=C2=A0 <&= lt; '\n';=C2=A0 =C2=A0 //< finish (magic)=C2=A0
=C2=A0
Note that printf (and other languages) already u= se special characters to modify the output, so having an '\n' is no= t abrupt.

But C++ streams are different, having to= spell out a special character is odd and unintuitive for a beginner and a = design deficiency in general.=C2=A0

=
It's only "magic" if you teach beginners that '\n= 9; is a special magic=20 command, rather than the literal representation of the newline=20 character.
=C2=A0
=C2=A0


=C2=A0

This screams some design flaw - we should be able to insert a new lines t= he same way we modify the stream!
Yes, t= he way to do that is with '\n'.
=C2=A0

On its own std:= :endl has the flaw that it does not obey the "do one thing" rule.=
Once we deprecate it, this will shut down all the naive tutorial= s/courses still teaching it as the default!=C2=A0

=
As for std::newline, we have options -=C2=A0

<= /div>
std::nl //< even a begin= ner can "read" it
std::newl //< orthogonal to endl
std::br //< why not at this point!
<= div>std::brl
std::bl

Geek= s can still use `\n`, but a beginner (and a teacher) will have a simple, correct,=C2=A0go-to option that models the syntax already introduced (= std::cout)!


On Friday, November 9, 2018 at 8:22:26 AM UTC= +2, PeterSommerlad wrote:
So the better way is do better teaching. I show my students that = they should not use endl, except when they need it.

Sent from Peter Sommerlad's=C2=A0iPad
+41 79 43= 2 23 32

On 8 Nov 2018, at 23:43, Hym= an Rosen <hyman...@gmail.com> wrote:

<= /div>
On Thu, Nov 8, 2018 at 5:08 PM Brian Bi &= lt;bbi...@gmail.com> wrote:
I think th= e reason why novices use std::endl is that they're under the impression= (no doubt perpetuated by incompetent educators) that std::endl is portable= whereas '\n' isn't.

I t= hink novices use std::endl because that's how C++ formatted I/O
was = presented for ages.=C2=A0 I have the feeling, completely unsupported
by = evidence, that the iostreams designers thought manipulators were
really = keen, and wanted to have one that would always get used.

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposal...@isocpp.org.
To post to this group, send email to std-pr...@isocpp.o= rg.
To view this discussion on the web visit https://groups.google.com/a/isocpp.org/= d/msgid/std-proposals/CAHSYqdYYZjeHHbRZ5bcHLYVsWfspwCeQ8oxEDRbuJ8dqAtsX5A%4= 0mail.gmail.com.

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposal...@isocpp.org.
To post to this group, send email to std-pr...@isocpp.o= rg.
To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposa= ls/b49f4c85-816b-4b35-851d-407061a8ef9f%40isocpp.org.


--
Brian Bi=

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit = https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/7da1f33f-c2c1-= 482f-8fc2-c23a9767a5ec%40isocpp.org.


--
Brian Bi

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit h= ttps://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAMmfjbMHae%3Dp= bG7LMjjjqWAE-5Zaiwi3rpWXr-HpwBRo0bjvfA%40mail.gmail.com.
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