Re: Future of debian-cd

[Hans Ginzel <hans@matfyz.cz>]

On Wed, Jan 07, 2004 at 06:00:51PM +0100, Jan Kesten wrote:
> # Datei lesen
> open DATEI, "<$dateiname" or die "$dateiname laesst sich nicht oeffnen\n";

   Use the $! variable (man perlvar; perldoc perlvar; www.perldoc.com):
open DATEI, "<$dateiname" or die "Datei `$dateiname' laesst sich nicht oeffnen: $!\n";

> @zeilen = <DATEI>  or die "$dateiname ist nicht lesbar\n"
> close DATEI;

   close DATEI or warn "Cannot close file `$dateiname': $!\n";

> # sortieren

   You can sort just by reading:

	@sorted_zeilen = sort <DATEI> or die $!;

> - ---- SNIP ----
>
> And the python way looks like this:
>
> # Datei lesen
> try:
>     datei = open(dateiname, 'r')
>     zeilen = datei.readlines()
>     datei.close()
> except IOError:
>     print dateiname, "ist nicht lesbar"
>     sys.exit( 1 )

   That's not what is above in perl. I understand especially: you
are saying that Python has exceptions. But Perl also has! Read about
`eval' in man perlfunc or `perldoc -f eval'. The advantidge of using
"die" for each part of code is that you can give more precise error
message, even more if combined with the `$!' variable. Above Python code
would be almost ekvivalently rewritten into Perl:

eval {
	open DATEI, "<$dateiname" or die $!;
	@zeilen = <DATEI> or die $!;
	close DATEI;
}
die "Datei `$dateiname' ist nicht lesbar: $@\n" if $@;

> Some other thing is that python knows about classes :-) But I do not

   Perl also knows about classes (perldoc -f bless; man perlboot,
perltoot, perlobj).

> want to start a discussion about pro perl or python :-)

   Nor want I, but be precise.

	Best regards

						Hans Ginzel