A little disappointed so far

[Ian Bicking]

On Mon, 2003-05-19 at 02:38, Alex Martelli wrote:
> >> open ($file) || die "Couldn't open $file"
> >> strikes me as rather readable. And concise.
> > 
> > In Python, just write:
> > f = open(file)
> > 
> > If there is an exception, an error message will be generated explaining
> > why the file could not be opened and your script will terminate.
> > 
> > The problem with your Perl code is that it doesn't really help with
> > problem diagnosis i.e. does the file not exist, is it a directory, do I
> > not have the necessary permissions, etc.
> 
> That's just because the die statement's argument above isn't using the
> normal idiomatic Perl form, which would be:
> 
>     die "Couldn't open data file $file: $!"
> 
> where the $! gives the details of the error.  Not Perl's fault for
> once -- it's just as possible to erroneously and anti-idiomatically
> omit printing the error details in a Python except clause.

You have to go to more trouble with the Python, like:

try:
    f = open(file)
except IOError, e:
    print "Couldn't open %s" % file
    # Equivalent improvement:
    # print "Couldn't open %s: %s" % (file, e)

If you don't try to handle the error yourself, you get a long-winded and
distracting traceback, but you also get the appropriate message.  The
"idiom" for primitive error handling is nil -- don't do anything, and
errors happen loudly and with some diagnostic information.  So I think
it *is* Perl's fault that doing even primitive error handling requires
an idiom.  

But arguing on Perl's flaws is probably silly in a Python group...

  Ian