Change the name of ArrayBoundsException in druntime

[Andrei Alexandrescu]

Denis Koroskin wrote:
> On Wed, 22 Oct 2008 19:06:24 +0400, Andrei Alexandrescu 
> <SeeWebsiteForEmail at erdani.org> wrote:
> 
>> Jarrett Billingsley wrote:
>>> On Wed, Oct 22, 2008 at 6:49 AM, Jacob Carlborg <doobnet at gmail.com> 
>>> wrote:
>>>> I think the name ArrayBoundsException should be changed to a more 
>>>> general
>>>> name like BoundsException, OutOfBoundsException or
>>>> IndexOutOfBoundsException. Then you can use the exception in every 
>>>> class
>>>> that have some sort of index operation and not just for an array/array
>>>> class.
>>>>
>>>  2nded.
>>
>> I agree. In fact I wanted to ask you all the following question. What do
>> you think about the current exception hierarchy in phobos? I think it is
>> terrible. Each module in std you open, the first piece of code to be
>> seen is the "class ThisModuleNameException" definition. In many (most?)
>> cases the module-specific exception does absolutely nothing in addition
>> to its base class. The putative reader (including me) tends to scroll 
>> non-critically over that passage without even blinking, mumbling in a 
>> trance - of course, yes, each module should define at least one 
>> exception type.
>>
>> Until one day when you stop scrolling and say, wait a minute. This all 
>> is repetition. And there are alternatives to catching by type - you 
>> can catch the base type and consult a field. And in fact I don't 
>> remember seeing code that depends on exceptions thrown from different 
>> modules having different types. There's something wrong here!
>>
>> I think most exception classes in phobos should be yanked if it's 
>> possible for their functionality (often nil) to be moved in the 
>> Exception base class. The module name should be a member. If someone 
>> needs to deal with an exception thrown from a specific module, they 
>> can always inspect the field. We don't need a huge hierarchy for that.
>>
>>
>> Andrei
> 
> There is sometimes a need to differentiate between a specific exception 
> and a generic one, even though the former or does nothing.
> 
> typedef Exception MyException; // might be a good compromise
> 
> try {
>     throw new MyException("reason");
> } catch (MyException e) {
>     // catch concrete exception
> } catch (Exception e) {
>     // catch generic exception
> }
> 
> This code currently doesn't work, because compiler thinks that 
> MyException and Exception are of the same type, which is wrong - 
> MyException is kind of a subclass of Exception, as the following sample 
> shows:
> 
> typedef Exception MyException;
> 
> void main()
> {
>     MyException me = new MyException("reason");
>     Exception e = me; // implicit downcast
>     me = e; // doesn't work, it is an upcast
>     Object o = me; // ICE! :)
> }
> 
> Could anyone put it into bugzilla? (I have no access to HTTP currently :()

I'd discussed that with Walter. He said that making typedefs
full-fledged classes would be technically difficult.

Andrei