Review of std.net.isemail part 2

[Andrei Alexandrescu]

On 4/3/11 4:38 PM, Jonathan M Davis wrote:
> On 2011-04-03 13:13, Jacob Carlborg wrote:
>> Why is this better? This is just like the pointless aliases you want to
>> avoid. Why do we even have a bool type in the language if we're going to
>> replace it with enums all the time?
>
> Andrei has been pushing for this, because it makes the calls to the function
> easier to read. If it's CheckDns.yes, then it's clear what you wanted, whereas
> if it were true, you'd have to look up whether true meant that it's supposed
> to check or skip checking. In some cases, that's more useful than others, but
> it's already becoming fairly common in Phobos that such explicit enums are
> used rather than bools.

This becomes painfully obvious in calls with more than one 
Boolean-encoded categorical argument.

auto r = getWidget("widget", true, false);

The topic is discussed in the book Code Complete and I suppose in many 
other style guides.


Andrei