220 36437 <98aadf70-3c33-476a-af1e-3fed88bf4789@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Ryan Nicholl Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: operator[](...) 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It is confusing and could be misconstrued as an array index by newer users to the language. Yes, there is a work around, but this is a workaround to something that shouldn't need to be worked around as it makes it more difficult to use and understand the language. (/sarcasm) On Saturday, December 16, 2017 at 11:40:42 AM UTC-5, Jack Adrian Zappa wrote: > > > > On Saturday, November 25, 2017 at 4:11:21 PM UTC-5, Nicol Bolas wrote: >> >> On Saturday, November 25, 2017 at 2:08:25 PM UTC-5, Ryan Nicholl wrote: >>> >>> >>> My suggestion is to allow overloading operator [] with multiple >>> arguments, e.g.: >>> >>> class image >>> { >>> ... >>> public: >>> ... >>> >>> pixel & operator[](size_t x, size_t y) >>> { >>> return internal_data[x+y*width]; >>> } >>> }; >>> >>> /// used like: >>> >>> image my_image = ...; >>> ... >>> pixel px = my_image[5, 3]; >>> >>> Would be most useful where I see >>> [{...}] >>> >>> currently. E.g.: >>> output[{x,y}] = value; >>> when processing images. >>> >>> >> You've essentially undermined your proposal by highlighting a problem >> with most multi-argument `[]` proposals. >> >> As it currently stands `output[x, y]` already has a meaning. Namely, it's >> equivalent to `output[y]`; the entire text between the `[]` is taken as a >> single expression, rather than a list of arguments. >> >> So you have to invent a new syntax to make what you want possible. >> Namely, `output[{x, y}]`. >> > > Why would anyone currently want to use a comma separated list inside of a > `[]` is beyond me. It is confusing and could be misconstrued as a > multidimensional array index by newer users to the language. Yes, there is > a work around, but this is a workaround to something that shouldn't need to > be worked around as it makes it more difficult to use and understand the > language. > -- 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/98aadf70-3c33-476a-af1e-3fed88bf4789%40isocpp.org. ------=_Part_31592_1647229906.1514680815988 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Why would anyone currently want to overloaded operator `[]` is beyond me.=C2=A0 It is confusing and could be misconstrued as an a= rray index by newer users to the language.=C2=A0 Yes, there is a work around, but this is a workaround to something that shouldn't= =20 need to be worked around as it makes it more difficult to use and=20 understand the language. (/sarcasm)

On Saturday, December 16, 2017 a= t 11:40:42 AM UTC-5, Jack Adrian Zappa wrote:


On Saturday, November 25, 2017 at 4= :11:21 PM UTC-5, Nicol Bolas wrote:
On Saturday, November 25, 2017 at 2:08:25 PM UTC-5, Ryan = Nicholl wrote:

= My suggestion is to allow overloading operator [] with multiple arguments, = e.g.:

class image
{
=C2=A0 ...
public:
=C2=A0 .= ...

=C2=A0 pixel & operator[](size_t x, size_t y)
=C2=A0 {
=C2=A0 =C2=A0 return internal_data[x+y*width];
=C2=A0 }
};

/// used like:

= image my_image =3D ...;
...
pixel px =3D my_image[5, 3];

Would be most useful where I see
[{...}]
=
currently. E.g.:
output[{x,y}] =3D value;
when processing images.
<= br>

You've essentially undermined your proposal b= y highlighting a problem with most multi-argument `[]` proposals.

As= it currently stands `output[x, y]` already has a meaning. Namely, it's= equivalent to `output[y]`; the entire text between the `[]` is taken as a = single expression, rather than a list of arguments.

So you have to i= nvent a new syntax to make what you want possible. Namely, `output[{x, y}]`= ..

Why would anyone currently want= to use a comma separated list inside of a `[]` is beyond me.=C2=A0 It is c= onfusing and could be misconstrued as a multidimensional array index by new= er users to the language.=C2=A0 Yes, there is a work around, but this is a = workaround to something that shouldn't need to be worked around as it m= akes it more difficult to use and understand the language.
<= /blockquote>

--
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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/98aadf70-3c33-476a-af1e-3fed88bf4789= %40isocpp.org.
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