2016-07-28 17:03 GMT+02:00 Stefan Glienke :
> I agree with Michael here. While in Spring4D our nullables have the
> implicit
> operator in both directions in retrospective I think it's not a good idea
> and
> the nullable -> x conversion should be explicit (with the possibility to
> raise an expli
2016-07-28 17:58 GMT+02:00 Michael Van Canneyt :
> Then you will not have this problem; GetValue will always return a
> 'Default' value.
IMO bad design. You can't use value of not assigned nilable types as same
as you can't use not assigned pointers >.<.
There is no magic in ^ . Just look at de
On Thu, 28 Jul 2016, Maciej Izak wrote:
2016-07-28 16:37 GMT+02:00 Michael Van Canneyt :
Are there additional benefits I have missed ?
Using nilable (I think nilable is better than nullable) records is terrible
without default field:
=== code begin ===
var
n: TNilable;
x: TRec;
begin
2016-07-28 17:49 GMT+02:00 Maciej Izak :
> === code begin ===
>
> var
> n: TNilable;
> begin
> {
>
>... let say that n is assigned somewhere, assume that n.HasValue = true
>
> }
> x.foo1 := 10;
> x.foo2 := 'abc';
> end.
>
> === code end ===
>
small typo. n instead of x ;)
--
Best
2016-07-28 16:37 GMT+02:00 Michael Van Canneyt :
>
> Are there additional benefits I have missed ?
>
>
Using nilable (I think nilable is better than nullable) records is terrible
without default field:
=== code begin ===
var
n: TNilable;
x: TRec;
begin
{
... let say that n is assigned s
> Well, I think this addition is not necessary, maybe even dangerous.
> I can live with the 'ascetic' version :-)
>
> Since the following:
>
> Procedure SomeTest(Var X : Integer);
>
> begin
>X:=1;
> end;
>
> Var
>A : TNullable;
>
> begin
>SomeTest(A^);
> end.
>
> Will lead to a c
On Thu, 28 Jul 2016, Dmitry Boyarintsev wrote:
On Thu, Jul 28, 2016 at 10:37 AM, Michael Van Canneyt <
mich...@freepascal.org> wrote:
[+] Default field (even if it is only syntactic sugar)
can-o'worms:
Wasn't there a discussion to have multiple default fields depending on the
type?
[-]
On Thu, Jul 28, 2016 at 10:37 AM, Michael Van Canneyt <
mich...@freepascal.org> wrote:
> [+] Default field (even if it is only syntactic sugar)
>
can-o'worms:
Wasn't there a discussion to have multiple default fields depending on the
type?
thanks,
Dmitry
_
On Thu, 28 Jul 2016, Maciej Izak wrote:
2016-07-28 14:59 GMT+02:00 Michael Van Canneyt :
Because with the exception of the ^ operator, I see no need for any special
constructions to achieve a "nullable type", except maybe some implicit
constructor/destructor ?
procedure with var parameter
2016-07-28 14:59 GMT+02:00 Michael Van Canneyt :
> Because with the exception of the ^ operator, I see no need for any special
> constructions to achieve a "nullable type", except maybe some implicit
> constructor/destructor ?
>
procedure with var parameter is special case, we need somehow to per
On Thu, 28 Jul 2016, Maciej Izak wrote:
2016-07-28 13:30 GMT+02:00 Michael Van Canneyt :
Assume a is null before the call to test1:
test1(a);
That won't compile.
1. What happens if this procedure is empty, i.e. no write is performed ?
(or it is performed conditionally)
On ret
2016-07-28 13:02 GMT+02:00 Stefan Glienke :
> One thing that I did not see mentioned here is the fact that introducing
> "operator hoisting" by introducing that default feature will not solve
> nullables
> at all.
>
In most of cases we can solve that by class operators but I think that for
few ca
2016-07-28 13:30 GMT+02:00 Michael Van Canneyt :
>
> Assume a is null before the call to test1:
>
> test1(a);
>
That won't compile.
>
> 1. What happens if this procedure is empty, i.e. no write is performed ?
>(or it is performed conditionally)
>On return, is a null or not ?
>
You are
On Thu, 28 Jul 2016, Maciej Izak wrote:
2016-07-28 12:40 GMT+02:00 Michael Van Canneyt :
I don't see how you can solve nullable var parameters in native code.
I'd like to present how TNullable works in my implementation (compilable
and runable program ;)
Yes, I remember you demonstrate
2016-07-28 12:40 GMT+02:00 Michael Van Canneyt :
> I don't see how you can solve nullable var parameters in native code.
>
I'd like to present how TNullable works in my implementation (compilable
and runable program ;)
=== code begin ===
procedure Test1(var x: Integer);
begin
x := 1;
end;
pro
2016-07-28 11:42 GMT+02:00 Sven Barth :
> ...That's where Maciej's idea for the "default" keyword came from, cause
> that allows something similar for array properties...
That is it! Thanks for detailed descriptions for others. All is expressed
in right way.
--
Best regards,
Maciej Izak
_
One thing that I did not see mentioned here is the fact that introducing
"operator hoisting" by introducing that default feature will not solve nullables
at all.
I think a basic rule of nullables (at least in C# where I know them from) is the
fact that operators can only be applied to a nullable i
On Thu, 28 Jul 2016, Sven Barth wrote:
Am 27.07.2016 23:27 schrieb "Jonas Maebe" :
Before continuing, I think it would be a good idea to look at what the
desired concept is exactly (transparent proxy objects/references, thin
wrappers that allow to specify some default behaviour, nullable typ
Am 27.07.2016 23:27 schrieb "Jonas Maebe" :
> Before continuing, I think it would be a good idea to look at what the
desired concept is exactly (transparent proxy objects/references, thin
wrappers that allow to specify some default behaviour, nullable types, ...
?) already exists in other programmi
19 matches
Mail list logo
