• Vinay Sajip (14/14) Oct 17 2019 Are arrays and objects part of a unified type system?
• Andrea Fontana (4/18) Oct 17 2019 Did you try templates? It seems easier:
• Adam D. Ruppe (5/6) Oct 17 2019 No, they are separate. You can define a class that contains an
• Vinay Sajip (9/15) Oct 17 2019 The use case is that I have a specialised comparator function

Vinay Sajip <vinay_sajip yahoo.co.uk> writes:

Are arrays and objects part of a unified type system? 
Specifically, if I do

void foo(Object x) {
     if (typeid(x) == typeid(Object[])) {
         auto a = cast(Object[]) x;
     }
}

I get a compilation error:

onlineapp.d(3): Error: cannot cast expression x of type 
object.Object to Object[]

What's the way to achieve the cast, which should be safe given 
the typeid check?

Thanks and regards,

Vinay Sajip

Andrea Fontana <nospam example.com> writes:

On Thursday, 17 October 2019 at 12:19:03 UTC, Vinay Sajip wrote:
 Are arrays and objects part of a unified type system? 
 Specifically, if I do

 void foo(Object x) {
     if (typeid(x) == typeid(Object[])) {
         auto a = cast(Object[]) x;
     }
 }

 I get a compilation error:

 onlineapp.d(3): Error: cannot cast expression x of type 
 object.Object to Object[]

 What's the way to achieve the cast, which should be safe given 
 the typeid check?

 Thanks and regards,

 Vinay Sajip

Did you try templates? It seems easier:
https://run.dlang.io/is/BbkTCw

Andrea

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

On Thursday, 17 October 2019 at 12:19:03 UTC, Vinay Sajip wrote:
 Are arrays and objects part of a unified type system?

No, they are separate. You can define a class that contains an 
array, but it doesn't work like that automatically.

You'll want to use a wrapper class or a variant type or a 
template or something for this depending on your exact use case.

Vinay Sajip <vinay_sajip yahoo.co.uk> writes:

On Thursday, 17 October 2019 at 12:40:33 UTC, Adam D. Ruppe wrote:
 On Thursday, 17 October 2019 at 12:19:03 UTC, Vinay Sajip wrote:
 Are arrays and objects part of a unified type system?

 No, they are separate. You can define a class that contains an 
 array, but it doesn't work like that automatically.

 You'll want to use a wrapper class or a variant type or a 
 template or something for this depending on your exact use case.

The use case is that I have a specialised comparator function 
that takes any two objects, including potentially array  of 
objects, and processes things accordingly. Perhaps a Variant will 
be the best bet, as the decision as to how to process has to be 
made at run time rather than compile time, and effectively based 
on user inputs.

Thanks for the suggestions,

Vinay Sajip