If I want a catch-all catch, which should I be using.

Out of habit I use Exception, but if I do that then I will miss some things thrown from Phobos.

Is it the intention that Throwable be used for this purpose?

Steve Teale wrote:
> If I want a catch-all catch, which should I be using.
> 
> Out of habit I use Exception, but if I do that then I will miss some things thrown from Phobos.
> 
> Is it the intention that Throwable be used for this purpose?
> 

Yes.

Walter Bright schrieb:
> Steve Teale wrote:
>> If I want a catch-all catch, which should I be using.
>>
>> Out of habit I use Exception, but if I do that then I will miss some things thrown from Phobos.
>>
>> Is it the intention that Throwable be used for this purpose?
>>
> 
> Yes.

Why is it possible to throw an Object?
I think "throw" and "catch" should be restricted to Throwable and
derived types.

On Sun, 03 May 2009 09:57:02 +0400, Frank Benoit <keinfarbton@googlemail.com> wrote:

> Walter Bright schrieb:
>> Steve Teale wrote:
>>> If I want a catch-all catch, which should I be using.
>>>
>>> Out of habit I use Exception, but if I do that then I will miss some
>>> things thrown from Phobos.
>>>
>>> Is it the intention that Throwable be used for this purpose?
>>>
>>
>> Yes.
>
> Why is it possible to throw an Object?
> I think "throw" and "catch" should be restricted to Throwable and
> derived types.

This is going to be addressed, so no worries.

Frank Benoit wrote:
> Walter Bright schrieb:
>> Steve Teale wrote:
>>> If I want a catch-all catch, which should I be using.
>>>
>>> Out of habit I use Exception, but if I do that then I will miss some
>>> things thrown from Phobos.
>>>
>>> Is it the intention that Throwable be used for this purpose?
>>>
>> Yes.
> 
> Why is it possible to throw an Object?
> I think "throw" and "catch" should be restricted to Throwable and
> derived types.

Because Phobos did not contain Throwable until the advent of druntime. This was sufficiently recent that Walter has not yet modified the compiler accordingly, or, most likely, noticed or decided to do so.

Christopher Wright Wrote:

> Frank Benoit wrote:
> > Walter Bright schrieb:
> >> Steve Teale wrote:
> >>> If I want a catch-all catch, which should I be using.
> >>>
> >>> Out of habit I use Exception, but if I do that then I will miss some things thrown from Phobos.
> >>>
> >>> Is it the intention that Throwable be used for this purpose?
> >>>
> >> Yes.
> > 
> > Why is it possible to throw an Object?
> > I think "throw" and "catch" should be restricted to Throwable and
> > derived types.
> 
> Because Phobos did not contain Throwable until the advent of druntime. This was sufficiently recent that Walter has not yet modified the compiler accordingly, or, most likely, noticed or decided to do so.

When that is done, and the object being thrown has been checked out, would it be a good idea for the compiler to automatically populate the file and line members of the Throwable?

Steve Teale wrote:
> Christopher Wright Wrote:
> 
>> Frank Benoit wrote:
>>> Walter Bright schrieb:
>>>> Steve Teale wrote:
>>>>> If I want a catch-all catch, which should I be using.
>>>>>
>>>>> Out of habit I use Exception, but if I do that then I will miss some
>>>>> things thrown from Phobos.
>>>>>
>>>>> Is it the intention that Throwable be used for this purpose?
>>>>>
>>>> Yes.
>>> Why is it possible to throw an Object?
>>> I think "throw" and "catch" should be restricted to Throwable and
>>> derived types.
>> Because Phobos did not contain Throwable until the advent of druntime. This was sufficiently recent that Walter has not yet modified the compiler accordingly, or, most likely, noticed or decided to do so.
> 
> When that is done, and the object being thrown has been checked out, would it be a good idea for the compiler to automatically populate the file and line members of the Throwable?

Hrm. You want to assign the file and line numbers where the exception is thrown, but not if you are rethrowing the exception.

The runtime has something like _d_throw; if the signature included __FILE__ and __LINE__ for the throw expression, that should work.

Christopher Wright Wrote:

> Steve Teale wrote:
> > Christopher Wright Wrote:
> > 
> >> Frank Benoit wrote:
> >>> Walter Bright schrieb:
> >>>> Steve Teale wrote:
> >>>>> If I want a catch-all catch, which should I be using.
> >>>>>
> >>>>> Out of habit I use Exception, but if I do that then I will miss some things thrown from Phobos.
> >>>>>
> >>>>> Is it the intention that Throwable be used for this purpose?
> >>>>>
> >>>> Yes.
> >>> Why is it possible to throw an Object?
> >>> I think "throw" and "catch" should be restricted to Throwable and
> >>> derived types.
> >> Because Phobos did not contain Throwable until the advent of druntime. This was sufficiently recent that Walter has not yet modified the compiler accordingly, or, most likely, noticed or decided to do so.
> > 
> > When that is done, and the object being thrown has been checked out, would it be a good idea for the compiler to automatically populate the file and line members of the Throwable?
> 
> Hrm. You want to assign the file and line numbers where the exception is thrown, but not if you are rethrowing the exception.
> 
> The runtime has something like _d_throw; if the signature included __FILE__ and __LINE__ for the throw expression, that should work.

OK, I did not think it through, but it would save a lot of typing grief;

 ... , __FILE__, __LINE__);

every time you wanted to be careful.

On Sun, 03 May 2009 22:12:00 +0400, Steve Teale <steve.teale@britseyeview.com> wrote:

> Christopher Wright Wrote:
>
>> Steve Teale wrote:
>> > Christopher Wright Wrote:
>> >
>> >> Frank Benoit wrote:
>> >>> Walter Bright schrieb:
>> >>>> Steve Teale wrote:
>> >>>>> If I want a catch-all catch, which should I be using.
>> >>>>>
>> >>>>> Out of habit I use Exception, but if I do that then I will miss  
>> some
>> >>>>> things thrown from Phobos.
>> >>>>>
>> >>>>> Is it the intention that Throwable be used for this purpose?
>> >>>>>
>> >>>> Yes.
>> >>> Why is it possible to throw an Object?
>> >>> I think "throw" and "catch" should be restricted to Throwable and
>> >>> derived types.
>> >> Because Phobos did not contain Throwable until the advent of  
>> druntime.
>> >> This was sufficiently recent that Walter has not yet modified the
>> >> compiler accordingly, or, most likely, noticed or decided to do so.
>> >
>> > When that is done, and the object being thrown has been checked out,  
>> would it be a good idea for the compiler to automatically populate the file and line members of the Throwable?
>>
>> Hrm. You want to assign the file and line numbers where the exception is
>> thrown, but not if you are rethrowing the exception.
>>
>> The runtime has something like _d_throw; if the signature included
>> __FILE__ and __LINE__ for the throw expression, that should work.
>
> OK, I did not think it through, but it would save a lot of typing grief;
>
>  ... , __FILE__, __LINE__);
>
> every time you wanted to be careful.
>

PHP allows function definition like this:

void foo(Args args, string fileName = __FILE__, int line = __LINE__)
{
  // do stuff
}

You call it like this: "foo(args);" and correct file name and line number is passed, i.e. default arguments are evaluated at call site. Can we use the same trick for exceptions? Here is an example:

class Throwable
{
   this(string fileName = __FILE__, int line = __LINE__) { ... }
}

class Exception : Throwable
{
   this(string reason, string fileName = __FILE__, int line = __LINE__)
   {
       super(fileName, line);
       // ...
   }
}

On Sun, May 3, 2009 at 4:14 PM, Denis Koroskin <2korden@gmail.com> wrote:
> PHP allows function definition like this:
>
> void foo(Args args, string fileName = __FILE__, int line = __LINE__)
> {
>  // do stuff
> }

Hidden feature: D2 allows it too, at least with templates.

void Throw(T : Throwable, string file = __FILE__, int line = __LINE__)(T ex)
{
	ex.file = file;
	ex.line = line;
	throw ex;
}

void foobar()
{
	Throw(new Exception("o hai"));
}

void main()
{
	try
		foobar();
	catch(RangeError e)
		writefln("(%s: %d) %s", e.file, e.line, e.msg);
}

I did find a sort of bug when trying a slightly different implementation of this though - any kind of explicit instantiation of the Throw template causes the __FILE__ and __LINE__ to be evaluated in the scope of the template rather than at the call site.