I am a little concerned about the way the delete operator is used with arrays.

The documentation states that

"""
Particular keys in an associative array can be removed with the delete operator:


delete b["hello"];

This confusingly appears to delete the value of b["hello"], but does not, it
removes the key "hello" from the associative array.
"""

So how can one delete the object that the array slot "hello" points to? Does one have to use a temporary variable to store the pointer/reference and then call delete on that?

If so, it would mean that

SomeClass o=b["hello"]
delete o;

and

delete b["hello"]

wouldn't be the same. This is inconsistent with the way expressions and temporary variables are usually handled in C/C++ and also D.

int i=3+4;
int x=i+5;

yields the same result as

x=(3+4)+5;

I think this is pretty messy (and looking at the last sentence the author also seems to be aware of that). Also, as I understand it, one of the design goals of D is that code that looks the same as C/C++ code also behaves the same (see the switch statement). In C++ "delete b[i]" would delete the object in b[i], not the slot i of array b.

I think the main problem is that the delete operator is used for two different things at the same time. Maybe a cleaner solution would be to have a dedicated operator (or array "member function") to delete slots of an array.

Then one could write something like this in D:

deleteslot b["hello"];

and the ambiguity would be gone.

I have no idea wether it is still early enough to make such a change (I only recently stumbled upon D), but I think it would be a worthwhile thing to consider to ensure consistency within the language.

Hauke Duden wrote:
> I am a little concerned about the way the delete operator is used with arrays.
> 
> The documentation states that
> 
> """
> Particular keys in an associative array can be removed with the delete operator:
> 
> 
> delete b["hello"];
> 
> This confusingly appears to delete the value of b["hello"], but does not, it
> removes the key "hello" from the associative array.
> """
> 
> So how can one delete the object that the array slot "hello" points to? Does one
> have to use a temporary variable to store the pointer/reference and then call
> delete on that?
> 
> If so, it would mean that
> 
> SomeClass o=b["hello"]
> delete o;
> 
> and
> 
> delete b["hello"]
> 
> wouldn't be the same. This is inconsistent with the way expressions and
> temporary variables are usually handled in C/C++ and also D.
> 
> int i=3+4;
> int x=i+5;
> 
> yields the same result as
> 
> x=(3+4)+5;
> 
> I think this is pretty messy (and looking at the last sentence the author also
> seems to be aware of that). Also, as I understand it, one of the design goals of
> D is that code that looks the same as C/C++ code also behaves the same (see the
> switch statement). In C++ "delete b[i]" would delete the object in b[i], not the
> slot i of array b.
> 
> I think the main problem is that the delete operator is used for two different
> things at the same time. Maybe a cleaner solution would be to have a dedicated
> operator (or array "member function") to delete slots of an array.
> 
> Then one could write something like this in D:
> 
> deleteslot b["hello"];
> 
> and the ambiguity would be gone.
> 
> I have no idea wether it is still early enough to make such a change (I only
> recently stumbled upon D), but I think it would be a worthwhile thing to
> consider to ensure consistency within the language.
> 

deleteslot is almost as confusing as delete, why not
Object[wchar[]] hashtbl;
...
hashtbl.remove( "foo" );
or
hashtbl.remove["foo"];

or will other objects have `manipulators` in the form
<name> object '[' <params> ']'

like the perl where
restore $foo a,b,c; => $foo->restore( a, b, c );

"Hauke Duden" <Hauke_member@pathlink.com> wrote in message news:bjuudk$nth$1@digitaldaemon.com...
> I am a little concerned about the way the delete operator is used with
arrays.
>
> The documentation states that
>
> """
> Particular keys in an associative array can be removed with the delete
operator:
>
>
> delete b["hello"];
>
> This confusingly appears to delete the value of b["hello"], but does not,
it
> removes the key "hello" from the associative array.

I agree it's inconsistent, and it bothers me, too.

How about this syntax:

	array_var.remove(index_val);

???

"Russ Lewis" <spamhole-2001-07-16@deming-os.org> wrote in message news:bobuqu$1017$1@digitaldaemon.com...
> How about this syntax:
>
> array_var.remove(index_val);

probably something like that will have to be done.