On Tue, Aug 15, 2000 at 04:12:17PM -0700, Peter Scott wrote:
> >Would someone please enlighten me as to the purpose of an explicit "try."
>
> Well, for one, it makes it easier to see that a block is subject to
> exception handling if all you have to do is look at the beginning for 'try'
> rathe
On Tue, Aug 15, 2000 at 10:52:02PM -0400, Chaim Frenkel wrote:
> Why does all the unwinding stuff have to be there? Let $@ exist in
> the always block the iff $@ is defined then you are unwinding and
> do your wishes. Otherwise you are just falling out of the BLOCK.
>
> Why all the extra syntax?
On Tue, Aug 15, 2000 at 05:14:56PM -0700, Peter Scott wrote:
> You want: while handling an exception, throwing another exception pushes
> the first one onto a stack which could be reported en masse when the coup
> de gras arrives. Like VMS error cascading. You do this with a _link
> attribute
On Tue, Aug 15, 2000 at 06:23:57PM -0600, Tony Olekshy wrote:
> Jonathan Scott Duff wrote:
> >
> > What's wrong with just using the switch statement? It seems
> > like except and catch are becoming special-purpose switches
> > to me. Is it really necessary?
>
> It's not necessary, but it is th
> "PS" == Peter Scott <[EMAIL PROTECTED]> writes:
>> Please include the comments about global variables and action at a distance.
PS> I'm sorry, my brain is fried. Can you spell out for me what you mean in
PS> this context and I'll put it in.
I am adamant against increasing the number of
Sorry, I keep reading it, even with your explanation, as "ignore this type".
A more positive word would be better.
I think the entire structure is too complex (is baroque the right term?).
I haven't seen a good reason that it should be any more complex than
do BLOCK
oops
Peter Scott wrote:
>
> Tony Olekshy wrote:
> >
> >finally { ... }
> >
> > Invoked whether or not unwinding. If the finally block
> > throws then unwinding starts or continues, if finally
> > doesn't throw then the unwinding state is not changed.
> > Inside the
Chaim Frenkel wrote:
>
> Tony Olekshy wrote:
> >
> > except { ... } => catch { ... }
> >
> > Invoked if unwinding and the except block returns true.
> > In the except block, $@ is the current exception.
> > If the except or catch blocks throw, unwinding continues.
> > If both co
David L. Nicol wrote:
>
> What if "try" were implied by the appearance of "catch" keywords,
> which expire at the close of their block?
>
> Would someone please enlighten me as to the purpose of an explicit
> "try."
The "try" is not necessarily for Perl's sake. It's for the
programmer's sake.
Jonathan Scott Duff wrote:
>
> What's wrong with just using the switch statement? It seems
> like except and catch are becoming special-purpose switches
> to me. Is it really necessary?
It's not necessary, but it is the whole point of it all.
Try is "just" a special-purpose if, except is a sp
At 12:35 AM 8/15/00 -0600, Tony Olekshy wrote:
>What if we implemented something like the following?
>finally { ... }
>
> Invoked whether or not unwinding. If the finally block
> throws then unwinding starts or continues, if finally
> doesn't throw then the unwinding s
Hmm, it now appears that everything on this subject has to go to
perl6-language-errors and perl6-language-flow.
At 03:26 PM 8/15/00 -0400, Chaim Frenkel wrote:
> > "PRL" == Perl6 RFC Librarian <[EMAIL PROTECTED]> writes:
>
>PRL> RFC 80 proposes standard exception classes and methods for core
At 08:11 PM 8/15/00 +, David L. Nicol wrote:
>What if "try" were implied by the appearance of "catch" keywords, which
>expire at the close of their block?
>
> catch [EXCEPTION [, ...] ] BLOCK
> ,...
> BLOCK
This is definitely a nifty concept that strikes me as very Per
At 03:55 PM 8/15/00 -0700, you wrote:
>LIST: perl6-language-errors
>CHAIR: Steve Simmons <[EMAIL PROTECTED]>
>MISSION:To develop RFCs related to error handling and exceptions
> in Perl 6, possibly combining existing RFCs into a more
> cohe
On Mon, Aug 14, 2000 at 05:43:08PM -0700, Peter Scott wrote:
> >IMHO trading six RFCs for two will greatly improve the chance of passing.
>
> As I've said before, I don't think there's a competition here.
My remark was poorly phrased, sorry. I was trying to say that a single
proposal which is
On Sun, Aug 13, 2000 at 07:35:06PM -0700, Peter Scott wrote:
> At 03:30 PM 8/13/00 -0500, David L. Nicol wrote:
> >Whose RFC deals with this?
> 63, 70, 80, 88 and 96. There would appear to be a groundswell of interest :-)
Well yes, but they represent three authors with (as best I can tell)
pr
On Tue, Aug 15, 2000 at 08:11:55PM +, David L. Nicol wrote:
[ nifty tryless code snipped ]
> The reason is, this way, we don't have to keep track of, are we in
> a try or not, while running. We always are. An error happens, we
> back out of blocks until we find an appropriate catch if any.
>Maintainer: Peter Scott <[EMAIL PROTECTED]>
>Date: 8 Aug 2000
>Last-Modified: 14 Aug 2000
>Version: 3
>Mailing List: [EMAIL PROTECTED]
>Number: 63
> An exception handling mechanism is proposed with the following syntax:
>
> exception EXCEPTI
> "PRL" == Perl6 RFC Librarian <[EMAIL PROTECTED]> writes:
PRL> RFC 80 proposes standard exception classes and methods for core exceptions.
PRL> This RFC doesn't need to repeat those, but it can expound upon the
PRL> semantics that exception classes ought to have. Assume wlog that they
PRL>
At 06:01 PM 8/15/00 +0100, Graham Barr wrote:
>Also, I have come to dislike the name `exception', its too long for me :)
>and who says we have to copy everyone else.
>
>Lookin in the thesaurus we get
>
>[Nouns] nonconformity [more]; unconformity, disconformity;
>unconventionality, informality, abn
On Tue, Aug 15, 2000 at 06:01:33PM +0100, Graham Barr wrote:
> As perl is an exceptional language itself, why not have
> `freaks' instead :)
How about just "oops"? :-)
-Scott
--
Jonathan Scott Duff
[EMAIL PROTECTED]
On Tue, Aug 15, 2000 at 11:47:03AM -0500, Jonathan Scott Duff wrote:
> On Tue, Aug 15, 2000 at 11:47:32AM +0100, Graham Barr wrote:
> > On Mon, Aug 14, 2000 at 10:56:36AM -0500, Jonathan Scott Duff wrote:
> > > try { }
> > > catch SomeException { }
> > > catch SomeOtherException { }
> > >
On Tue, Aug 15, 2000 at 11:43:41AM -0500, Jonathan Scott Duff wrote:
> On Mon, Aug 14, 2000 at 08:50:41PM -0600, Tony Olekshy wrote:
> > Jonathan Scott Duff wrote:
> > > try { }
> > > catch { # ALL exceptions
> > > switch ($@) {
> > >
On Tue, Aug 15, 2000 at 11:47:32AM +0100, Graham Barr wrote:
> On Mon, Aug 14, 2000 at 10:56:36AM -0500, Jonathan Scott Duff wrote:
> > try { }
> > catch SomeException { }
> > catch SomeOtherException { }
> > finally { }
> >
> > which seems to only catch exceptions based on name.
On Mon, Aug 14, 2000 at 08:50:41PM -0600, Tony Olekshy wrote:
> Jonathan Scott Duff wrote:
> > try { }
> > catch { # ALL exceptions
> > switch ($@) {
> > case ^_->name eq 'IO' { ... }
> > case ^_->canFoo
This and other RFCs are available on the web at
http://dev.perl.org/rfc/
=head1 TITLE
Exception handling syntax
=head1 VERSION
Maintainer: Peter Scott <[EMAIL PROTECTED]>
Date: 8 Aug 2000
Last-Modified: 14 Aug 2000
Version: 3
Mailing List: [EMAIL PROTECTED]
> "TO" == Tony Olekshy <[EMAIL PROTECTED]> writes:
TO> except { ... } => catch { ... }
TO> Invoked if unwinding and the except block returns true.
TO> In the except block, $@ is the current exception.
TO> If the except or catch blocks throw, unwinding continues.
TO> If bo
On Mon, Aug 14, 2000 at 10:56:36AM -0500, Jonathan Scott Duff wrote:
> On Mon, Aug 14, 2000 at 04:09:41AM -0600, Tony Olekshy wrote:
> > $@->CanFoo is an example of semantics that determines whether or
> > not the exception is caught; stringification may be an example
> > of semantics that comes i
On Mon, Aug 14, 2000 at 10:15:21PM -0700, Peter Scott wrote:
> At 08:56 PM 8/14/00 -0600, Tony Olekshy wrote:
> >consider this:
> >
> > try { may_throw_1; }
> > catch { may_throw_2; }
> > catch { may_throw_3; }
> > finally { may_throw_4; }
>
> That's either a syntax error
Jonathan Scott Duff <[EMAIL PROTECTED]> writes:
> On Sun, Aug 13, 2000 at 10:51:24PM -0700, Peter Scott wrote:
> > Could be. I'd be interested in seeing non-OOP proposals that do what I
> > want exceptions to do, I have a hard time imagining one.
>
> Well, what is it that you want exceptions t
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