On Monday, 31 July 2017 at 07:50:57 UTC, inevzxui wrote:
On Monday, 31 July 2017 at 07:16:25 UTC, Cecil Ward wrote:
Say I have used Typedef! to create some new type and I declare
a variable, constant or enum of that type. Is there a way that
I can express a literal value on the rhs without having to use
casts, as that seems to defeat the point of the nice type
safety?
I may be asking for the impossible or _illogical_ here. In any
case, I still get to keep the nice feature of not being able
to mix up types with assignment from one variable to another.
Specific example is
mac_addr_48_t my_mac_address = 0x112233445566uL;
Which now produces a compile time error after I changed to use
an alias = Typedef!uint64_t as opposed to just a straight
alias = uint64_t earlier with no strong typing.
If struct + alias this is not strong enough the only solution
is see is a helper template à la "octal" or "hexString", i.e a
static cally checked string.
I suspect that I am asking for something that literally makes no
sense at all. I wanted to try and avoid opening the door to
allowing the following kind of typing error now, eg
enum ip_address = 0x11223344;
mac_addr_48_t my_mac = cast(mac_addr_48_t) ip_address;
as if we are going to the bother of introducing strong type
checking with Typedef! then the last thing I want to do is
encourage is a proliferation of casts.
I realise something else now too -
Issue 2: The thing is that I also immediately have to do a lot of
work to make the simplest operators work anyway, such as in
foreach( addr; base_mac_address .. base_mac_address + range )
where the + operator is producing compile-time errors now.
So it just seems that the Typedef! feature immediately make life
into a nightmare. I don't know if something based of the physical
units module (using 'dimensionless' in this case) would work -
perhaps it only handles floating point of various types? Or
whether that would also involve a huge amount of work and still
have issue 1 mentioned earlier. In any case, I have absolutely no
clue how to even begin to start using the units module thing.
