Re: [boost] [chrono/date] validated versus valid dates

Subject: Re: [boost] [chrono/date] validated versus valid dates
From: Rob Stewart (robertstewart_at_[hidden])
Date: 2013-05-06 20:34:58

On May 6, 2013, at 5:40 AM, "Vicente J. Botet Escriba" <vicente.botet_at_[hidden]> wrote:

> Le 06/05/13 00:21, Rob Stewart a écrit :
>>> 
>> The basic idea is reasonable, but I suggest a couple of alternatives. First, I see no value in making is_validated() public. Second, validate() should return void:
>> 
>> void
>> date::validate()
>> {
>>    if (!is_valid())
>>    {
>>       throw bad_date();
>>    }
>> }
>> 
>> bool
>> date::is_valid()
>> {
>>    if (validated())
>>    {
>>       return true;
>>    }
>>    // do validation
>>    if (valid)
>>    {
>>       validated_ = true;
>>    }
>>    return valid;
>> }
>> 
>> Usage:
>> 
>> date d1;
>> d1.validate(); // throws bad_date
>> date d2(year(2013), may, day(5));
>> d2.validate();
>> assert(d2.is_valid());
> I thought about this alternative. As is_valid must be const, this request validated_ to be mutable. I wanted to use one of the unused bits to store this information and I don't know if I can declare a bitfield mutable. Can I?

I don't think so, but the value can be mutable, which would allow you to manipulate the needed nit.

___
Rob

(Sent from my portable computation engine)