Can you explain the result?

PerlOnTheWay has asked for the wisdom of the Perl Monks concerning the following question:

sub func {
    my ($delimiter, $text) = @_;
    return 1 and 0;
}

use Data::Dumper;
print Dumper(func());
[download]

guess what?

the result is $VAR1 = 1;

anyone knows the reason?

seems that Perl gives return the same priority as an ordinary sub,is this really a good design?

Comment on Can you explain the result? Select or Download Code

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Re: Can you explain the result? by choroba (Cardinal) on Dec 06, 2011 at 13:26 UTC
Mind the difference between `return 1 and 0` [download] and `return 1 && 0` [download]	[reply] [d/l] [select]
Re^2: Can you explain the result? by Anonymous Monk on Dec 06, 2011 at 13:32 UTC
I know `and` has lower priority than `&&`,but it doesn't explain this issue.	[reply] [d/l] [select]
Re^3: Can you explain the result? by choroba (Cardinal) on Dec 06, 2011 at 13:33 UTC
It does. Try with print instead of return to see.	[reply]
Re^4: Can you explain the result? by Anonymous Monk on Dec 06, 2011 at 13:36 UTC
Re^5: Can you explain the result? by Utilitarian (Vicar) on Dec 06, 2011 at 14:17 UTC
Re^5: Can you explain the result? by MidLifeXis (Monsignor) on Dec 06, 2011 at 18:01 UTC
Re^5: Can you explain the result? by Anonymous Monk on Dec 06, 2011 at 15:09 UTC
Re: Can you explain the result? by RMGir (Prior) on Dec 06, 2011 at 13:20 UTC
Sure. The result of your function is the value 1, and that's what you're passing to Dumper... Now, if you called `print Dumper(\&func);` [download] on the function reference, you'd get a slightly more interesting result: `$VAR1 = sub { "DUMMY" };` [download] I guess my version of Dumper isn't up to decompiling subs - I'm guessing that's expected. Mike	[reply] [d/l] [select]
Re^2: Can you explain the result? by PerlOnTheWay (Monk) on Dec 06, 2011 at 13:24 UTC
shouldn't `1 and 0` be `false/0`?	[reply] [d/l] [select]
Re^3: Can you explain the result? by RMGir (Prior) on Dec 06, 2011 at 13:34 UTC
As choroba said, return 1&&0 is different from return 1 and 0. `$ perl -MB::Deparse -e' sub f{return 1 and 0;}; sub g{return 1 && 0}; $deparse=B::Deparse->new(); print "f(): ",$deparse->coderef2text(\&f),"\n"; print "g(): ",$deparse->coderef2text(\&g),"\n";' f(): { 0 if return 1; } g(): { return 0; }` [download] Mike	[reply] [d/l]
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Re: Can you explain the result? by TJPride (Pilgrim) on Dec 06, 2011 at 16:33 UTC
Rather than worrying about why Perl does this, it may be simpler to just do `return (1 and 0);`	[reply] [d/l]


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