On 2013-11-25 13:00, Marco Leise wrote:
Am Fri, 22 Nov 2013 02:55:44 +0100
schrieb Simen Kjærås <[email protected]>:
On 22.11.2013 00:50, Meta wrote:
On Thursday, 21 November 2013 at 22:51:43 UTC, inout wrote:
What if you have more that just one validation, e.g. Positive and
LessThan42?
Is Positive!LessThan42!int the same type as LessThan42!Positive!int?
Implicitly convertible?
Allow multiple validation functions. Then a Validated type is only valid
if validationFunction1(val) && validationFunction2(val) &&...
Validated!(isPositive, lessThan42, int) validatedInt =
validate!(isPositive, lessThan42)(34);
//Do stuff with validatedInt
I believe inout's point was this, though:
Validated!(isPositive, lessThan42, int) i = foo();
Validated!(isPositive, int) n = i; // Fails.
Validated!(lessThan42, isPositive, int) r = i; // Fails.
This is of course less than optimal.
If a type such as Validate is to be added to Phobos, these problems need
to be fixed first.
Can you write a templated assignment operator that
accepts any Validated!* instance and builds the set difference
of validation functions that are missing on the assigned value?
E.g. in the case of n = i: {isPositive} / {isPositive,
lessThan42} = emtpy set.
Do you mean this?
Validated!(int, isPositive, lessThan42) a =
validated!(isPositive, lessThan42)(13);
Validated!(int, isPositive) b = a;
a = b; // Only tests lessThan42
If so, you're mostly right that this should be done. I am however of the
opinion that conversions that may throw should be marked appropriately,
so this will be the right way:
a = validated!(isPositive, lessThan42)(b); // Only tests lessThan42
New version now available on GitHub:
http://git.io/hEe0MA
http://git.io/QEP-kQ
--
Simen
