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Postings from October 1999
So, you want to default a value if it's not set, what a great idea! my $val1 = shift || "default-value"; $val2 ||= "default-value"; Or you want to check for errors, also great! $foo = sometest() or die "barf"; But, soon you use this on a math function or something which needs the value 0 and run into the standard problem of the value 0. So you do one of the standards: my $val1 = (defined $_[0]) ? $_[0] : "default-value"; $val = "default" if (!defined $val) $foo = sometest(); (defined $foo) or die "barf"; All of that nasty repetition of the tested variable seems so anti-perl! And we all hate extra keystrokes so! I'd like to suggest 3 new operators ordef (like or) ||| (like ||) |||= (like ||=) Which have the definition of only passing control to evaluate the second argument if the first is undefined. Now we have the excellent code: my $val1 = shift ||| "default-value"; $val2 |||= "default-value"; $foo = sometest() ordef die "barf"; Note how close it is to the first version which broke on 0 (or ""), which is the reason for adding all three operators. Plus the new operators would generate much better optimized code! What's the big deal? Well, looking through the standard modules alone, I found over 80 cases which could benefit inside ext, then gave up before counting in lib, which has REAMS of examples! I started hacking this out, but when I got to needing the right version of byacc I realized that the chances of my getting it right are small. I'll plod on if others wish... (and perhaps for the education also.) -WilsonThread Next