220 32119 <61acd2a4-d2f8-41ef-849a-0c47cee485d1@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: HarD Gamer Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Allow constexpr static data members in a literal type. 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It could be worked around by making yes and no functions.= =20 > > Should we make this legal? It seems reasonable for types to offer=20 > constants scoped under their own name, and if they are literal types,=20 > that these constants can be constexpr.=20 > --=20 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 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/61acd2a4-d2f8-41ef-849a-0c47cee485d1%40isocpp.or= g. ------=_Part_2728_1204495269.1492620315571 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
https://groups.google.com/a/isocpp.org/forum/#!topic/std-p= roposals/pSHhUp0-7so

Em domingo, 26 de mar=C3=A7o de 2017 11:30:29 U= TC-3, Avi Kivity escreveu:
Con= sider this type-safe bool class:


=C2=A0 =C2=A0template <typename Tag>

=C2=A0 =C2=A0class bool_class {

=C2=A0 =C2=A0 =C2=A0 =C2=A0bool _value;

=C2=A0 =C2=A0public:

=C2=A0 =C2=A0 =C2=A0 =C2=A0explicit constexpr bool_class(bool v) noexce= pt : _value(v) {}

=C2=A0 =C2=A0 =C2=A0 =C2=A0// more emulation of bool

=C2=A0 =C2=A0 =C2=A0 =C2=A0static constexpr bool_class yes =3D bool_cla= ss{true};

=C2=A0 =C2=A0 =C2=A0 =C2=A0static constexpr bool_class no =3D bool_clas= s{true};

=C2=A0 =C2=A0};


Compilation fails, I believe rightly, on clang, because by the time yes= =20
and no are parsed, bool_class is an incomplete type, and therefore not = a=20
literal type. =C2=A0It could be worked around by making yes and no func= tions.

Should we make this legal? =C2=A0It seems reasonable for types to offer= =20
constants scoped under their own name, and if they are literal types,= =20
that these constants can be constexpr.

--
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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 https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/61acd2a4-d2f8-41ef-849a-0c47cee485d1= %40isocpp.org.
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