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From: Maciej Sobczak (prog_at_[hidden])
Date: 2005-09-15 04:55:08

Stephen Gross wrote:

> Since the assignment check is done at runtime (as it has to be), why make
> the range restriction at compile time? Isn't it more useful to have a class
> that works more like this:
> === CODE ===
> CheckedIntegralValue x;
> x.setLowerLimit(-5);
> x.setUpperLimit(1000);
> x = 10;
> x = 9000; // Fails at runtime
> ===========
> Does this make sense?

Yes, it does, except:

- it means that the limits are run-time properties of each object, which
adds to their size (likely 3 times!)

- it means that you cannot use the bounds for static deductions, which
can actually ensure that if some operations are always safe, then no
run-time checks are necessary (and therefore there is no overhead) or on
the contrary, if the operation is always wrong then there is no sense to
even allow it to compile.

The only advantage of the run-time approach is that you can set the
limits based on the information that is not yet available at
compile-time (like bounds read from the database).

In my opinion both approaches have their uses, just like std::vector and

Maciej Sobczak

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