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digitalmars.D - error vs exception

reply Ben Hinkle <bhinkle4 juno.com> writes:
I'm confused about what D calls errors and exceptions. Part of the changes
that I've made to std.stream involve changing the Error subclasses to
Exception subclasses and I want to make sure this is the right thing to do.

Now, the doc http://www.digitalmars.com/d/errors.html talks about the class
Error and how it can be caught and handled. It also says all errors
subclass Error. So that makes me think Errors are recoverable. But then in
object.d the source code says:

// Recoverable errors
class Exception : Object ...
// Non-recoverable errors
class Error : Exception ...

I'm used to Exceptions being thrown/caught willy-nilly and Errors being
really serious problems that cause the app to abort. In D is it reversed?
If so then I'll back out my std.stream changes. Also I suggest some more
details in the errors.html doc about the different classes involved and
maybe even rename Exception to NonRecoverableError or something (or
vide-versa rename Error to NonRecoverableException).

Note I don't want to start a thread about the abstract concepts of
recoverable vs non-recoverable errors - I just want to know how those
concepts map to D.

-Ben
Aug 23 2004
parent reply Sean Kelly <sean f4.ca> writes:
In article <cgcs6d$2ele$1 digitaldaemon.com>, Ben Hinkle says...
I'm confused about what D calls errors and exceptions. Part of the changes
that I've made to std.stream involve changing the Error subclasses to
Exception subclasses and I want to make sure this is the right thing to do.

Now, the doc http://www.digitalmars.com/d/errors.html talks about the class
Error and how it can be caught and handled. It also says all errors
subclass Error. So that makes me think Errors are recoverable. But then in
object.d the source code says:

// Recoverable errors
class Exception : Object ...
// Non-recoverable errors
class Error : Exception ...

I'm used to Exceptions being thrown/caught willy-nilly and Errors being
really serious problems that cause the app to abort. In D is it reversed?
If so then I'll back out my std.stream changes. Also I suggest some more
details in the errors.html doc about the different classes involved and
maybe even rename Exception to NonRecoverableError or something (or
vide-versa rename Error to NonRecoverableException).

Note I don't want to start a thread about the abstract concepts of
recoverable vs non-recoverable errors - I just want to know how those
concepts map to D.

I'm not sure. Though doFormat (a relatively new addition) throws an exception derived from Error, so I'm guessing that Walter currently considers Errors to be recoverable no matter what the comment says. Sean
Aug 23 2004
next sibling parent "Ben Hinkle" <bhinkle mathworks.com> writes:
 I'm not sure.  Though doFormat (a relatively new addition) throws an

 derived from Error, so I'm guessing that Walter currently considers Errors

 recoverable no matter what the comment says.

holy shiskabobs - you're right. Well, looks like I'll send Walter another version of std.stream with the old Error subclasses. Plus I'll start updating all my code to use Error subclasses instead of Exceptions.
Aug 24 2004
prev sibling parent Stewart Gordon <smjg_1998 yahoo.com> writes:
Sean Kelly wrote:

<snip>
 I'm not sure.  Though doFormat (a relatively new addition) throws an exception
 derived from Error, so I'm guessing that Walter currently considers Errors to
be
 recoverable no matter what the comment says.

Recoverable by whom - the app or the programmer? A FormatError strikes me as an indication of a bug. Stewart. -- My e-mail is valid but not my primary mailbox. Please keep replies on the 'group where everyone may benefit.
Aug 26 2004