On Wednesday, 15 June 2016 at 16:40:19 UTC, Andrei Alexandrescu
wrote:
One of the first things I looked for was establishing bounds
for numbers, like Smart!(int, 0, 100) for percentage. For all
its might, this package does not offer this basic facility, and
from what I can tell does not allow users to enforce it via
policies.
Another angle on why `checkedint` does not currently include a
bounded type: although some of the internals might be similar,
conceptually a `BoundInt` type is actually the *opposite* of the
ideal which `SmartInt` and `SafeInt` strive toward.
The problem which this package was written to solve, is that when
programming people frequently want to use "integers" as a data
type. A real "integer" is, by definition, UNbounded, with an
infinite range of values available. This makes designing
algorithms simpler, but of course leads to problems when a value
strays outside the narrow range in which the behaviour of machine
integers correctly emulates that of mathematical integers.
The whole point of `checkedint` is to be able to write algorithms
based on the simplifying assumption that your variables behave
like real, UNbounded mathematical integers, secure in the
knowledge that an error message will be generated if that
assumption is invalidated.
Intentionally limiting values to a specific range is a different
problem, and never the one that I was trying to solve - although
I agree that the `checkedint` package would be a good namespace
in which to park a `BoundInt` type, if someone wants to submit
one.
