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Re: Almost Always Auto? (was Re: Substitution failure can be an error)

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Jorgen Grahn <grahn+nntp@snipabacken.se> writes:

> On Fri, 2019-11-22, Vir Campestris wrote:
>
>> When I read "auto x = somefunction()" I don't know what x is.  Unless I
>> look at the declaration.  Which if I'm unlucky is one of several
>> overloads with template type deduction from the parameters.
>>
>> But IMHO reading matters more.  You'll only write it once.
>
> I tend to agree.  I use auto, but try to be careful so it won't be a
> problem when I revisit the code, like my duck typing exercises are in
> Python.

I don't have a lot of experience with "auto" in C++, but a fair
amount of experience with type inference (and not needing type
annotations in many cases) in other programming languages.  I
don't have any hard and fast rule, but generally I find it works
well to give an explicit type annotation only in those cases
where it's important to know exactly what the type is.  Probably
this rule carries over into C++ reasonably well, although the
two situations are not completely parallel.  In particular, C++
doesn't have partial types, except maybe for arrays -- it's
pretty much all or nothing, either a completely specified type
or none at all;  there is no way in C++ to say a type is "a list
of something, but I won't say what the something is".  But I
think the general rule is still good in the C++ domain.

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Substitution failure can be an error "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-18 18:49 +0100
  Re: Substitution failure can be an error Vir Campestris <vir.campestris@invalid.invalid> - 2019-11-18 21:54 +0000
  Re: Substitution failure can be an error Sam <sam@email-scan.com> - 2019-11-18 18:12 -0500
  Re: Substitution failure can be an error Melzzzzz <Melzzzzz@zzzzz.com> - 2019-11-19 03:53 +0000
    Re: Substitution failure can be an error "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-19 12:48 +0100
      Re: Substitution failure can be an error Melzzzzz <Melzzzzz@zzzzz.com> - 2019-11-19 19:48 +0000
        Re: Substitution failure can be an error "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-19 21:31 +0100
          Re: Substitution failure can be an error Melzzzzz <Melzzzzz@zzzzz.com> - 2019-11-19 21:20 +0000
            Re: Substitution failure can be an error "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-19 22:51 +0100
              Re: Substitution failure can be an error Melzzzzz <Melzzzzz@zzzzz.com> - 2019-11-19 21:58 +0000
            Re: Substitution failure can be an error David Brown <david.brown@hesbynett.no> - 2019-11-20 09:19 +0100
              Re: Substitution failure can be an error Öö Tiib <ootiib@hot.ee> - 2019-11-20 02:16 -0800
                Re: Substitution failure can be an error scott@slp53.sl.home (Scott Lurndal) - 2019-11-20 14:13 +0000
                Re: Substitution failure can be an error Öö Tiib <ootiib@hot.ee> - 2019-11-20 08:34 -0800
                Re: Substitution failure can be an error David Brown <david.brown@hesbynett.no> - 2019-11-21 12:34 +0100
                Re: Substitution failure can be an error Öö Tiib <ootiib@hot.ee> - 2019-11-21 05:29 -0800
                Re: Substitution failure can be an error David Brown <david.brown@hesbynett.no> - 2019-11-21 15:58 +0100
          Re: Substitution failure can be an error Christian Gollwitzer <auriocus@gmx.de> - 2019-11-20 11:12 +0100
            Re: Substitution failure can be an error Öö Tiib <ootiib@hot.ee> - 2019-11-20 04:25 -0800
              Re: Substitution failure can be an error Öö Tiib <ootiib@hot.ee> - 2019-11-20 06:05 -0800
      Almost Always Auto? (was Re: Substitution failure can be an error) Vir Campestris <vir.campestris@invalid.invalid> - 2019-11-22 21:46 +0000
        Re: Almost Always Auto? (was Re: Substitution failure can be an error) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-11-23 09:29 +0000
          Re: Almost Always Auto? (was Re: Substitution failure can be an boltar@nowhere.co.uk - 2019-11-23 17:23 +0000
          Re: Almost Always Auto? (was Re: Substitution failure can be an error) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 12:46 -0800
        Re: Almost Always Auto? (was Re: Substitution failure can be an error) "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-24 00:26 +0100
          Re: Almost Always Auto? (was Re: Substitution failure can be an error) "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-24 00:28 +0100
          Re: Almost Always Auto? (was Re: Substitution failure can be an error) "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-24 00:45 +0100
          Re: Almost Always Auto? (was Re: Substitution failure can be an boltar@nowhere.co.uk - 2019-11-24 10:47 +0000
            Re: Almost Always Auto? (was Re: Substitution failure can be an Melzzzzz <Melzzzzz@zzzzz.com> - 2019-11-24 13:37 +0000
              Re: Almost Always Auto? (was Re: Substitution failure can be an boltar@nowhere.co.uk - 2019-11-25 11:08 +0000
  Re: Substitution failure can be an error Manfred <noname@add.invalid> - 2019-11-20 18:46 +0100
    Re: Substitution failure can be an error "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-21 06:02 +0100
      Re: Substitution failure can be an error Manfred <noname@add.invalid> - 2019-11-21 15:50 +0100

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