• Charles Hixson via Digitalmars-d-learn (7/7) May 14 2015 What are the downsides to simulating a new type with a struct.
• Laeeth Isharc (2/9) May 14 2015 http://dlang.org/phobos/std_typecons.html#.Typedef
• Charles Hixson via Digitalmars-d-learn (20/32) May 14 2015 Yes, that looks as if it would do the job, but what are its advantages
• Adam D. Ruppe (7/9) May 14 2015 None really, except perhaps automatic forwarding of operators
• Charles Hixson via Digitalmars-d-learn (3/12) May 14 2015 Thank you. I was hoping that struct was a good approach, I've just
• tired_eyes (3/19) May 15 2015 FWIW, I've seen a lot of user-defined types made with structs in

Charles Hixson via Digitalmars-d-learn writes:

What are the downsides to simulating a new type with a struct.

What I have in mind is something along the lines of:

struct myType
{  uint64_t  value;
}

The goal of this type is to prevent accidental conversions from myType 
into ints, uint64_ts, etc.

"Laeeth Isharc" <laeeth nospamlaeeth.com> writes:

On Thursday, 14 May 2015 at 18:42:56 UTC, Charles Hixson wrote:
 What are the downsides to simulating a new type with a struct.

 What I have in mind is something along the lines of:

 struct myType
 {  uint64_t  value;
 }

 The goal of this type is to prevent accidental conversions from 
 myType into ints, uint64_ts, etc.

Charles Hixson via Digitalmars-d-learn writes:

On 05/14/2015 01:42 PM, Laeeth Isharc via Digitalmars-d-learn wrote:
 On Thursday, 14 May 2015 at 18:42:56 UTC, Charles Hixson wrote:
 What are the downsides to simulating a new type with a struct.

 What I have in mind is something along the lines of:

 struct myType
 {  uint64_t  value;
 }

 The goal of this type is to prevent accidental conversions from 
 myType into ints, uint64_ts, etc.



Yes, that looks as if it would do the job, but what are its advantages 
over a simple struct?  I'd be hesitant to try to predict the RAM layout 
of a templated variable, but it's my understanding that a struct has 
neither compile time nor runtime penalties over a simple variable, and 
that it doesn't increase RAM comsumption when included within another 
struct, or in a static array.

What I was really wondering was whether the limitation of access caused 
by enclosing a variable within a struct was worth the benefit.  
Templates add a whole 'nother layer of complexity.  For that matter I 
was thinking that, if I so chose, I could at some point add limits along 
the lines of Ada's types.  I like being *able* to define conversions for 
types, but frequently I'd rather not have them arbitrarily assumed.  
Otherwise I'd just use alias, which almost does what I want.  (E.g., one 
thing I might eventually want to do is use a couple of bits at the top 
of the uint64_t as flags, so if I did define operations I'd need to be 
able to mask the flag bits off before the operation and reapply them to 
the result, in some defined way of combining the flags.  Not good if 
sometimes the value is going to be automatically reinterpreted as a 
plain number.)

"Adam D. Ruppe" <destructionator gmail.com> writes:

On Friday, 15 May 2015 at 01:03:32 UTC, Charles Hixson wrote:
 Yes, that looks as if it would do the job, but what are its 
 advantages over a simple struct?

None really, except perhaps automatic forwarding of operators 
which is easy enough to do on a struct too (and with a struct, 
you can do only the ones that actually make sense for you).

Typedef has a few major disadvantages too - surprising behavior 
if you forget the second parameter, for example. The library 
typedef should really be removed.

Charles Hixson via Digitalmars-d-learn writes:

On 05/14/2015 06:38 PM, Adam D. Ruppe via Digitalmars-d-learn wrote:
 On Friday, 15 May 2015 at 01:03:32 UTC, Charles Hixson wrote:
 Yes, that looks as if it would do the job, but what are its 
 advantages over a simple struct?

 None really, except perhaps automatic forwarding of operators which is 
 easy enough to do on a struct too (and with a struct, you can do only 
 the ones that actually make sense for you).

 Typedef has a few major disadvantages too - surprising behavior if you 
 forget the second parameter, for example. The library typedef should 
 really be removed.

Thank you.  I was hoping that struct was a good approach, I've just 
never seen anyone recommending it, so I wanted to check.

"tired_eyes" <pastuhov85 gmail.com> writes:

On Friday, 15 May 2015 at 06:11:41 UTC, Charles Hixson wrote:
 On 05/14/2015 06:38 PM, Adam D. Ruppe via Digitalmars-d-learn 
 wrote:
 On Friday, 15 May 2015 at 01:03:32 UTC, Charles Hixson wrote:
 Yes, that looks as if it would do the job, but what are its 
 advantages over a simple struct?

 None really, except perhaps automatic forwarding of operators 
 which is easy enough to do on a struct too (and with a struct, 
 you can do only the ones that actually make sense for you).

 Typedef has a few major disadvantages too - surprising 
 behavior if you forget the second parameter, for example. The 
 library typedef should really be removed.

 Thank you.  I was hoping that struct was a good approach, I've 
 just never seen anyone recommending it, so I wanted to check.

FWIW, I've seen a lot of user-defined types made with structs in 
the code of C-ported libs, and was sure that is a common approach.