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digitalmars.D.learn - types of exceptions

reply "Ameer Armaly" <ameer_armaly hotmail.com> writes:
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Hi.
Maybe I'm missing something, but why does almost every module in phobos =
have its own type of exception, which is just a wrapper for the base =
class?

--=20



Ameer
---
Visit my blog at
http://ameerarmaly.blogspot.com
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 Usually it's your choice. You can whine or you can laugh.
--Animorphs
Nov 23 2005
next sibling parent MWolf <MWolf_member pathlink.com> writes:
In article <dm2o11$1t5e$1 digitaldaemon.com>, Ameer Armaly says...

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Hi.
Maybe I'm missing something, but why does almost every module in phobos =
have its own type of exception, which is just a wrapper for the base =
class?

--=20



Ameer
---
Visit my blog at
http://ameerarmaly.blogspot.com
---
Life is either tragedy or comedy.
 Usually it's your choice. You can whine or you can laugh.
--Animorphs
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<DIV><FONT face=3DArial size=3D2>Hi.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Maybe I'm missing something, but why =
does almost=20
every module in phobos have its own type of exception, which is just a =
wrapper=20
for the base class?</FONT></DIV><FONT face=3DArial size=3D2>
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href=3D"http://ameerarmaly.blogspot.com">http://ameerarmaly.blogspot.com<=
/A><BR>---<BR>Life=20
is either tragedy or comedy.<BR>&nbsp;Usually it's your choice. You can =
whine or=20
you can laugh.<BR>--Animorphs</FONT></DIV></BODY></HTML>

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So you can catch specific exceptions?
Nov 23 2005
prev sibling parent Chris Sauls <ibisbasenji gmail.com> writes:
Ameer Armaly wrote:

 Hi.
 Maybe I'm missing something, but why does almost every module in phobos 
 have its own type of exception, which is just a wrapper for the base class?
 
 Ameer


I'll give you an explanation by giving you an (heavily watered down) example
from one of 
my own projects.  This particular program runs one of a number of functions
based on user 
input ("command lines" essentially).  These functions, in turn, might throw one
of 
"InvalidArgsException" or "InvalidStateException."  Both of these are just
"empty 
children" as I like to say, or in other words:



(( On a side note, maybe it'd be nifty to be able to just use a semicolon in
these cases? 
  Something like 'class Foo : Bar;' ...or not, its personal taste, I suppose. ))

Now then, these functions get called with code along these lines:













meant)


So, while the new exceptions don't directly add any functionality, they allow
me to take 
real advantage of the try{}catch{} syntax.  The alternative is to use a single
Exception 
child with a "Type" enum.  Something like:
















But then my try{}catch{} turns into something like:




















I like the first way better, myself.  :)

-- Chris Sauls
Nov 26 2005