Change the name of ArrayBoundsException in druntime

[Robert Fraser]

Andrei Alexandrescu 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

Yes, you _could_ use a field... but the "catch a subclass" style is 
already there and is supported by the language, so _why_ use a field? 
Which of the following is easier?:

Option A:
---------
try
{
      new Socket(30587);
}
catch(SocketException e)
{
      printf("Could not open socket\n");
}

Option B:
---------
try
{
     new Socket(30587);
}
catch(Exception e)
{
     if(e.type == ExceptionType.Socket)
         printf("Could not open socket\n");
     else
         throw e;
}