String Exceptions (PEP 352)

[Thomas Guettler]

Hi,

I like python because it is compatible to old versions. That's way I think
string exceptions should not be deprecated.

I use string exceptions if the condition for an assertion is
to complex:

if foo and bar and i>10:
raise "if foo and bar i must not be greater than 10"

This way I can easily add "checkpoint s" to my code.

Is it too late to change this? Way not make this line

raise "..."

behave like this:

raise Exception("..." )

in the future?

I know that catching string exceptions and reading the
string is different from Exception("..." ). This could
become deprecated.

Please keep Python compatible to old versions.

Thomas Güttler

--
Thomas Güttler, http://www.thomas-guettler.de/
E-Mail: guettli (*) thomas-guettler + de
Spam Catcher: niemand.leerman n@thomas-guettler.de

[infidel]

Re: String Exceptions (PEP 352)

You could also use the "assert" statement:
[color=blue][color=green][color=darkred]
>>> if foo and bar:[/color][/color][/color]
.... assert i <= 10, "if foo and bar then i must not be greater than
10"
....

[bruno at modulix]

Re: String Exceptions (PEP 352)

Thomas Guettler wrote:[color=blue]
> Hi,
>
> I like python because it is compatible to old versions. That's way I think
> string exceptions should not be deprecated.
>
> I use string exceptions if the condition for an assertion is
> to complex:
>
> if foo and bar and i>10:
> raise "if foo and bar i must not be greater than 10"[/color]

What's wrong with:

assert foo and bar and i > 10, \
"if foo and bar i must not be greater than 10"



(snip)[color=blue]
>
> Please keep Python compatible to old versions.[/color]

<MHO>
When there's too much hysterical cruft and warts accumulated from the
past, it's time to throw away and clean up, even if it breaks a lot of
things. Trying to keep compatibility at any price would be just suicidal
IMHO - time to get rid of old warts and come back to simplicity. "one
obvious way to do it" rules.
</MHO>

--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb@xiludom. gro'.split('@')])"

[bruno at modulix]

Re: String Exceptions (PEP 352)

bruno at modulix wrote:[color=blue]
> Thomas Guettler wrote:
>[color=green]
>>Hi,
>>
>>I like python because it is compatible to old versions. That's way I think
>>string exceptions should not be deprecated.
>>
>>I use string exceptions if the condition for an assertion is
>>to complex:
>>
>>if foo and bar and i>10:
>> raise "if foo and bar i must not be greater than 10"[/color]
>
>
> What's wrong with:
>
> assert foo and bar and i > 10, \
> "if foo and bar i must not be greater than 10"
>[/color]

oops ! I meant:
if foo and bar:
assert i > 10, "if foo and bar i must not be greater than 10"

My bad :(


--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb@xiludom. gro'.split('@')])"

[Terry Reedy]

Re: String Exceptions (PEP 352)


"Thomas Guettler" <niemand.leerma nn@thomas-guettler.de> wrote in message
news:pan.2006.0 4.27.14.18.41.7 58387@thomas-guettler.de...[color=blue]
>I like python because it is compatible to old versions.[/color]

Python 3 will be a new and mostly improved dialect of Python.
Some 2.x code will run unchanged. Much will not. Transition tools will be
written.
[color=blue]
> That's way I think string exceptions should not be deprecated.
> Is it too late to change this?[/color]

Yes.
[color=blue]
> Way not make this line raise "..."
> behave like this: raise Exception("..." )[/color]

Part of the motivation for 3.0 is to remove duplication and *simply* the
language (= easier to learn), parser, compiler, and interpreter.

Terry Jan Reedy

[Ben Finney]

Re: String Exceptions (PEP 352)

Thomas Guettler <niemand.leerma nn@thomas-guettler.de> writes:
[color=blue]
> I like python because it is compatible to old versions.[/color]

I like it because it has a documented, manageable procedure for
breaking compatibility with old versions.
[color=blue]
> if foo and bar and i>10:
> raise "if foo and bar i must not be greater than 10"[/color]

Others have pointed out that this is a job for 'assert'.
[color=blue]
> Is it too late to change this?[/color]

Yes. PEP-0352 has a status of "Final".
[color=blue]
> Way not make this line
>
> raise "..."
>
> behave like this:
>
> raise Exception("..." )
>
> in the future?[/color]

Because explicit is better than implicit, and special magic behaviour
is to be deprecated (or never implemented) when possible.
[color=blue]
> Please keep Python compatible to old versions.[/color]

Have a read of PEP 0005:

<URL:http://www.python.org/dev/peps/pep-0005>

Also note that the transition plan (documented in the PEP that
concerns you) shows the support for the old behaviour is not to be
dropped until Python 3.0, a release explicitly targeted at breaking
backward compatibility to clean out crufty behaviour.

--
\ "I went to the hardware store and bought some used paint. It |
`\ was in the shape of a house." -- Steven Wright |
_o__) |
Ben Finney

[Paul Rubin]

Re: String Exceptions (PEP 352)

bruno at modulix <onurb@xiludom. gro> writes:[color=blue]
> What's wrong with:
>
> assert foo and bar and i > 10, \
> "if foo and bar i must not be greater than 10"[/color]

It doesn't necessarily do anything. With optimization enable, assert
is a no-op.

[bruno at modulix]

Re: String Exceptions (PEP 352)

Paul Rubin wrote:[color=blue]
> bruno at modulix <onurb@xiludom. gro> writes:
>[color=green]
>>What's wrong with:
>>
>>assert foo and bar and i > 10, \
>> "if foo and bar i must not be greater than 10"[/color]
>
>
> It doesn't necessarily do anything. With optimization enable, assert
> is a no-op.[/color]

quoting the OP (emphasis is mine):
"""
I use string exceptions if the condition for an *assertion* is
to complex:
"""

--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb@xiludom. gro'.split('@')])"