Re: [eigen] An insistent plea for an input operator

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

2010/7/20 Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>:
> On Tue, Jul 20, 2010 at 5:14 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
>> 2010/7/20 Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>:
>>>> Sure! How is this a problem?
>>>
>>> Not really but somebody might think hey, it accepts input from
>>> std::cin in the form of
>>>
>>> 1 2 3
>>> 4 5 6
>>>
>>> why not from a text file... I admit, we can easily deal with that. I
>>> was more like brainstorming. ;)
>>
>> Just for the record: I don't see how allowing reading from a text file
>> is a drawback, I see it as a feature :-)
>
> Of course it is! But not if it does not work even though it compiles.
> I requires a different method.
>
> Your other proposal sound fine to me as long as its fine for the user.
> I was actually hoping for something as the standard library does. You
> know, there are these modifiers. I don't recall perfectly, but they
> somehow look like this
>
> std::cout << std::ios_base::hex << 10 << std::endl;

The problem is that we can't extend that from the out side with our
own modifiers: that would require adding new data members in cout...

>
> or then with Eigen types like this
>
> std::cout << Eigen::Format(...) << m;
>
> or this
>
> std::cin >> Eigen::Format(...) >> m;

Ah, this looks possible. so here the  std::cout << Eigen::Format(...)
would return a stream of a different type, inheriting the type of the
original stream.

Benoit


>
> I would like this a lot since it were following the standard approach
> but the other one is fine too.
>
> - Hauke
>
>
>