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Re: 'Core' Language Philosophy

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Piers Cawley
December 2, 2003 05:16
Re: 'Core' Language Philosophy
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Michael Lazzaro <> writes:

> On Wednesday, November 26, 2003, at 12:29 PM, Larry Wall wrote:
>> If you contrast it with an explicit try block, sure, it looks
>> better.  But
>> that's not what I compare it with.  I compare it with Perl 5's:
>>     $opus.write_to_file($file) or die "Couldn't write to $file: $!";
>> That has some known problems with false positives, er, negatives,
>> which Perl 6 addresses with things like:
>>     $opus.write_to_file($file) err fail "Couldn't write to $file: $!";
>> But if we're going to talk about philosophy, we should talk about
>> Perl's notion of not forcing people to escalate all the way to
>> exceptions when a lesser form of undefinedness or falseness will do.
>> Perl 6 doesn't back off from this.  In fact, it takes it further
>> by allowing you to return unthrown exceptions as "undef".  And by
>> providing a "fail" that either returns or throws the exception
>> depending on the preferences of the caller.
> Well, yes, hmm, har, but...
> Speaking only for myself, my own (database-heavy) code already makes
> pretty extensive use of the differences between "false",
> "unknown/undefined/NULL", and "worthy of exception" -- all three of
> those conditions may exist at various times, and no two of them can
> reasonably be lumped together as being logically identical.

So implement a *real* NULL instead of trying to force 'undef'
somewhere it doesn't want to go. 

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