Re: [eigen] Feature proposal - add error string to help debug const/non-const mapping errors

[Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx>]

On 03.03.2013 00:58, Rohit Garg wrote:
> Hi all,
>
> I have been using the Map objects a lot lately, and I have seen that
> often, a simple mistake of mapping a const pointer as, say, MatrixXd.
> Obviously, this leads to a big compiler error, which is often
> difficult to decipher. I propose that a small error string be added to
> Map object, which will aid debugging. Something similar to
> "you_mixed_different_types_use_cast_function".
>
> This could prove very helpful. I know 3.2 beta is being planned, just
> how big a change is this?

I guess that's a rather small change (basically provide a const Scalar* 
constructor which has a static assertion).
But I would vote against suggesting to "use_cast" in the error string.
Maybe something like expecting_a_non_const_pointer or 
check_your_const_correctness, though this might be also a bit confusing 
to the novice (but it would be easier to provide a FAQ entry for that).

Christoph




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Dipl.-Inf., Dipl.-Math. Christoph Hertzberg
Cartesium 0.049
Universität Bremen
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