catching exceptions from an except: block

[Gabriel Genellina]

Re: catching exceptions from an except: block

En Fri, 09 Mar 2007 04:49:59 -0300, Gerard Flanagan
<grflanagan@yah oo.co.ukescribi ó:

Another version:
>
import exceptions

As back in time as I could go (Python 1.5), exceptions were available as
builtins...

def onfailFalse(fn) :
def inner(*args, **kwargs):
try:
return fn(*args, **kwargs)
except ABCException:
return False
return inner
>
@onfailFalse
def a(x):
if x == 1:
return 'function a succeeded'
else:
raise ABCException()

There is a serious flaw on this approach, the function can't return any
false value (it would be treated as a failure).

--
Gabriel Genellina

[Gabriel Genellina]

Re: catching exceptions from an except: block

En Fri, 09 Mar 2007 05:52:35 -0300, Duncan Booth
<duncan.booth@i nvalid.invalide scribió:

"Gabriel Genellina" <gagsl-py2@yahoo.com.a rwrote:
>

>Not the *previous* exception, but the *current* one. You must be
>inside an "except" clause to use a bare raise.
>>

No, you don't have to be inside an except clause to use a bare raise.
A bare 'raise' will re-raise the last exception that was active in the
current scope. That applies even outside the except clauses just so long
as there has been an exception within the same function:

Oh! Thanks, I didn't know that.
I tested it in the interpreter, outside any function, and the exception
info was lost immediately, so I wrongly concluded that it lived shortly.

--
Gabriel Genellina

[Gerard Flanagan]

Re: catching exceptions from an except: block

On Mar 9, 9:56 am, "Gabriel Genellina" <gagsl-...@yahoo.com.a rwrote:

En Fri, 09 Mar 2007 04:49:59 -0300, Gerard Flanagan
<grflana...@yah oo.co.ukescribi ó:
>

Another version:

>

import exceptions

>
As back in time as I could go (Python 1.5), exceptions were available as
builtins...
>

I did not know that. Thanks.

def onfailFalse(fn) :
def inner(*args, **kwargs):
try:
return fn(*args, **kwargs)
except ABCException:
return False
return inner

>

@onfailFalse
def a(x):
if x == 1:
return 'function a succeeded'
else:
raise ABCException()

>
There is a serious flaw on this approach, the function can't return any
false value (it would be treated as a failure).
>

I was teaching myself decorators more than anything, so it's not
thought out to any extent, but even so I don't think it's a "serious
flaw", rather it would be programmer error to use @onfailFalse on a
function that may return False. Don't you think?

Gerard

[Gabriel Genellina]

Re: catching exceptions from an except: block

En Fri, 09 Mar 2007 07:30:20 -0300, Gerard Flanagan
<grflanagan@yah oo.co.ukescribi ó:

>There is a serious flaw on this approach, the function can't return any
>false value (it would be treated as a failure).

>
I was teaching myself decorators more than anything, so it's not
thought out to any extent, but even so I don't think it's a "serious
flaw", rather it would be programmer error to use @onfailFalse on a
function that may return False. Don't you think?

I thought this was on response to the original problem, not for your own
problem.

--
Gabriel Genellina

[Gerard Flanagan]

Re: catching exceptions from an except: block

On Mar 9, 11:57 am, "Gabriel Genellina" <gagsl-...@yahoo.com.a r>
wrote:

En Fri, 09 Mar 2007 07:30:20 -0300, Gerard Flanagan
<grflana...@yah oo.co.ukescribi ó:
>

There is a serious flaw on this approach, the function can't return any
false value (it would be treated as a failure).

>

I was teaching myself decorators more than anything, so it's not
thought out to any extent, but even so I don't think it's a "serious
flaw", rather it would be programmer error to use @onfailFalse on a
function that may return False. Don't you think?

>
I thought this was on response to the original problem, not for your own
problem.
>

Mea culpa.

Gerard

[Gabriel Genellina]

Re: catching exceptions from an except: block

En Fri, 09 Mar 2007 08:14:18 -0300, Gerard Flanagan
<grflanagan@yah oo.co.ukescribi ó:

Mea culpa.

Ego te absolvo in nomine Patris Guidii et Filii Python et Spiritus Sancti
Computatorium.

--
Gabriel Genellina